The effects of fuel droplet size on soot formation in spray flames formed in a laminar counterflow are investigated experimentally and numerically. Sauter mean diameter (SMD) of quasi-monodispersed fuel spray (n-decane) is carefully controlled independently from the other spray characteristics using a fre- quency-tunable vibratory orifice atomizer, and the two-dimensional spatial distributions of soot volume fraction and soot particle size are measured by laser induced incandescence (LII) and time resolved LII (TIRE-LII), respectively. In addition, the soot formation processes are examined in detail by a two-dimen- sional direct numerical simulation (DNS) employing a kinetically based soot model with flamelet model. The results show that the soot formation area and location are strongly affected by the SMD of the fuel spray. As the SMD of the fuel spray increases, the average soot formation area expands, whereas local suppression of soot formation is instantaneously observed in the spray flames because of the appearance of groups of unburned droplets. The size of soot particles tend to be larger in the outer part of the soot formation area compared to soot in the inner part. This is because the surface growth of soot particles markedly proceeds compared to the coagulation and oxidation.

A two-dimensional direct numerical simulation is applied to spray flames formed in a laminar counterflow and turbulent jet flow, and effects of radiative heat transfer on the spray combustion characteristics and soot formation behavior is studied in detail. N-decane (C10H22) is used as a liquid fuel, and the droplet motion is calculated by the Lagrangian method. A one-step global reaction is employed for the combustion reaction model. A kinetically based soot formation model with the flamelet model is employed to predict soot formation. Radiation is taken into account by using the discrete ordinate method with the narrow band non-gray gas absorption model. The results show that the soot is formed in in the spray diffusion flame and its radiation emission increases with increasing the equivalence ratio. This trend is in good agreement with that of the luminous flame behavior observed in the experiment. The radiation is found to significantly affect the soot formation behavior. The extened flamelet/progress-variable approach which can consider interphase heat transfer such as radiation and latent heat is also proposed and discussed to apply the model to a practical problems by means of large-eddy simulation.

Experimental studies using 2t/d and 200t/d coal gasifier were carried out to investigate the inception criteria for entrainment of molten slag droplet in an entrained flow coal gasifier. It was clarified that average gas dynamic pressure and liquid film Reynolds number influenced strongly the phenomenon of entrainment of molten slag. The formula of the critical gas dynamic pressure and the critical Weber number, which could be applied to the large-scale gasifier, were obtained as inception criteria for the phenomenon. It was clearly shown that the flow pattern in the large-scale gasifier could be different from the smaller gasifier by means of numerical simulation analysis and that the critical velocity decreases relatively along with the scaling-up of the gasifier.

噴霧燃焼は種々エネルギー機器で用いられるが，燃料液滴と流体間の相互作用等のため，その挙動はガス燃焼に比べ極めて複雑であり，未だその詳細は明らかにされていない．そこで本研究では，直接数値計算を噴霧燃焼流に適用し，乱流燃焼モデリングの観点から噴霧火炎の詳細な挙動を明らかにした．すなわち，燃焼場の重要な特性量である混合分率やスカラー消散率に対する各物理量の依存性を調べ，噴霧火炎中の物理量はガス拡散火炎のものとは異なり，これら特性量のみでは決定し得ないことを明らかにした．また，火炎片モデルと速度論に基づくすす生成モデルのカップリングにより，噴霧火炎に対する輻射の影響やすす生成挙動の詳細を明らかにした．

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.fuel.2021.121520

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： https://doi.org/10.1007/s10494-021-00274-x

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this paper, the recent researches and developments on coal gasification modeling and simulation are described. Numerical models for the three chemical processes such as devolatilization, char gasification, and gas-phase reaction are reviewed and discussed for further development to improve accuracy. Recently the devolatilization models to describe the coal chemical structure with a simple expression have been proposed and validated on the laboratory-scale flames. It is essential to precisely model char gasification reaction as a rate-determining step and the formulation of the active sites sharing by the mixture and the pore structure formation are important in the modeling. It will become significant to take the elementary reactions into account in the gas phase reaction model. Large-eddy simulation of coal gasification on the laboratory-scale entrained flow gasifier is performed to demonstrate the numerical procedure. Results show the predicted temperature distribution qualitatively agrees with the experiment. Moreover, the gas-liquid-solid three-phase reacting flow simulation is preliminarily performed to capture the molten slag flow behavior within the gasifier. It is revealed that the three-phase simulation can give insight into the complex multiphase and multiphysics phenomena taking place within the gasifier to assess the design and the operating condition.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI:10.1016/ j.apt.2019.09.024

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI:10.1021/acs.energyfuels.9b01161

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.apt.2019.03.017

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Three formulations of quasi-two-dimensional flamelet (Q2DF) models are derived from the two-dimensional flamelet formulation on the basis of assumptions regarding the third stream (diluent), and these models are validated by means of a two-dimensional direct numerical simulation (DNS) of a three-feed non-premixed combustion system into which the diluent is injected as the third stream. DNS combined with the Arrhenius formation (ARF) together with a detailed mechanism is also performed as a reference case and compared with the present models. The characteristics of the flamelets in three-feed non-premixed combustion are discussed in detail for ARF in terms of the three mixture fractions, temperature, and major and minor species. Some discrepancies appeared between the ARF and the Q2DF models. The difference in the cross-scalar dissipation rates between Q2DF and the two-dimensional flamelet model is considered the major reason for the deviations. The cross-scalar dissipation rates for the reactor streams and the diluent are expected to be either positive or negative values in the two-dimensional flamelet model, whereas only positive numbers resulted in the Q2DF cases. And the cross-scalar dissipation rate for the fuel and the oxidizer in the Q2DF models are always negative which is also varied from that in the two-dimensional flamelet model. As the results are not determined solely by a single mixture fraction, one scalar dissipation rate is insufficient for establishing a complete database, and it is considered that an additional scalar dissipation rate is needed to improve the model. Overall, it is confirmed that the three Q2DF models presented in this study capture the fundamental characteristics of flamelets in the three-feed non-premixed combustion system, although further improvement is required.

DOI： DOI:10.1021/acs.energyfuels.9b00764

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s12206-019-0347-5

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.proci.2018.08.019

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.proci.2018.09.028

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Pulverized coal injection into blast furnace is the precious technology to decrease the iron making cost. To inject more pulverized coal, it is necessary to investigate the combustion behavior of pulverized coal around the tuyere and many numerical simulations as well as experiments have been carried out. In this paper, by using Extended CPD model which is new devolatilization model and Large Eddy Simulation model, the combustion behavior of individual pulverized coal particles was investigated. The volume fraction of CO+CO2 which is the indicator of how much carbon included in pulverized coal changed to gas phase was reasonably predicted by new simulation model. It is suggested the devolatilization processes of pulverized coals under 40 μm varied widely between individual particles.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this study, an experimental and a numerical investigations are performed to investigate the effect of particle’s shape and size distribution on its dispersion behavior. Firstly, particle dispersion of pulverized coal and spherical polymer particles is observed by Particle Image Velocimetry (PIV) technique in the experiment. Secondly, a simulation is performed to analyze the particle dispersion in detail. Spherical and spheroidal motion models are applied to particle’s movement to investigate the shape effect. Furthermore, monodisperse and polydisperse for particles are applied to investigate the size distribution effect on the dispersion. Experimental results show that in the jet turbulence flow, pulverized coal par- ticles, which have complex shapes and various sizes, have quite different dispersion behavior compared to spherical particles. In terms of the results of the simulation, this difference is mainly caused by the size distribution effect. Although particle’s shape affects the dispersity, it is weakened by the size distribution effect.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To investigate the effects of particle shape on the dispersion in an isotropic turbulent flow, herein two direct numerical simulations are performed. The six degrees of freedom motion of spherical and spher- oidal particles in a vertical uniform flow and a gas-particle two-way isotropic turbulent flow. The former, which is investigated using a numerical simulation with the Arbitrary Lagrangian-Euler (ALE) method, shows that a spheroidal particle travels with rotating and oscillating motions, which significantly affect the pressure and the friction force on the particle’s surface. The trend of the fluid force acting on the spheroidal particle’s surface also oscillates and differs from that on a spherical particle. The time variation of the fluid force on the spheroidal particle is modeled in the CD equation, which has a sine curve’s PDF relation with Rep and the particle’s maximum and minimum CD values. The latter simulation examines the effects of the particle shape on the dispersion with the motion model developed above. The particle’s dispersion behavior, which is analyzed by the statistical variable D and the Radial Distribution Function (RDF), shows that the dispersion motion is markedly affected by particle’s sphericity, especially for par- ticles with a relatively small sphericity. The results suggest that this difference can influence ignitability, flammability, and the concentration of combustible gases released by particles, and requires further study.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Effects of CO2 recirculation within an oxy-fuel IGCC plant on a gasification characteristics of a two-stage entrained flow coal gasifier was numerically investigated by means of a three-dimensional unsteady Reynolds-averaged Navier-Stokes(RANS) simulation. The RNG k ε model and the Eulerian-Lagrangian manner were used to consider the effect of turbulence and the particles' motions, respectively. A char gasification model in which the Langmuir-Hinshelwood formulation was coupled with the random pore model was employed to estimate gasification reaction rate. Results showed that the gasification per- formance such as the per pass carbon conversion efficiency for the oxy-fuel condition in which CO2 replaced N2 in the primary and secondary gas flows was in the same level for the air-blown condition in which O2 flowed into the gasifier with N2, while the gaseous temperature drastically decreased for the former case. It was also found that the gaseous temperature was recovered to the same level for the air- blown condition with at least more than 35% of oxygen concentration in the gasifying agent and simultaneously the highly gasification performance was observed. It is essential to control O2 and CO2 concentrations in the gasifying agent to turn the CO2 recirculation to advantage in utilization of the O2- CO2 blown gasifier in the oxy-fuel IGCC system.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To develop accurate models for the numerical simulation of coal combustion field, detailed experimental data using laser techniques, which can figure out the basic phenomena in a coal flame, are necessary. In particular, soot is one of the important intermediate substances in a coal flame. This paper is the first paper in the world reporting soot particle size distributions in a coal flame. The spatial distribution of the primary soot particle diameter were measured by the combination of the time-resolved laser induced incandescence (TiRe-LII) method and the thermophoretic sampling (TS) method. The primary soot particle diameter distribution was expressed by the log normal function based on the particle diameter measurement using SEM images obtained from the TS samples. The relative function between the signal decay ratio obtained by TiRe-LII and the primary soot particle diameter was defined based on the log normal function. Using the relative function, the spatial distributions of the primary soot particle diameter with the soot volume fraction were obtained. The results show that the small isolated soot regions instantaneously exist in the entire combustion field. This characteristics is different from spray combustion field. From the ensemble-averaged TiRe-LII images, it was found that the soot volume fraction and the primary soot particle diameter increases with increasing the height above the burner in any radial distance. It was also found that the volumetric ratio of small particles decreases with increasing radial distance at the region close to the burner exit. However, the variation of the soot particle diameter distribution along the radial direction becomes small in the downstream region. This tendency is caused by the turbulent mixing effect. It is expected that the accurate soot formation model will be developed in the near future by using the data reported in this paper.

DOI： 10.1299/jtst.2016jtst0049

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To investigate the effects of fuel NO formation models on the prediction of NO concentrations in a coal combustion field, numerical simulations for a coal combustion field in a 760 kW test furnace were performed. Three models, those proposed by De Soete, Chen et al. and Mitchell et al. were employed to calculate fuel NO formation originating from volatile matter. The results show that the model proposed by Mitchell et al. reproduces the tendency of the experimental data better than the other two models. In addition, the difference between the NO conversion ratios of bituminous coal and sub-bituminous coal that contains a high level of moisture was examined in detail using simulation results from the model of Mitchell et al. It was found that the formation of a region with a low oxygen mole fraction immediately downstream of a region with a high NO production rate is essential to realize a low NO conversion ratio.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Reaction kinetics of coal volatile were numerically investigated based on analyses during reaction mechanism reduction procedure in detail in this paper. Computation on a closed homogeneous reactor model was performed to clarify important chemical species and their reaction pathways with evaluating the capability of prediction of ignition delay time and chemical species concentration under a wide range of equivalence ratios and temperatures. The kinetics of large hydrocarbons such as polycyclic aromatic hydrocarbons (PAH) that comprise a large portion of combustion features for complex hydrocarbon materials was focused on in a coal flame. The data computed here was analyzed through the combined process of the directed relation graph with error propagation and sensitivity analysis (DRGEPSA) and the computational singular perturbation (CSP) that can evaluate the roles of each species and reaction pathway respectively in the chemical system. Results show that hydrocarbons such as aromatics, methyl and ethyl groups play important role in the ignition and flame propagation processes. Finally, the skeletal mechanism including 64 species and 150 reactions was derived from the detailed mechanism that consists of 257 species and 1107 reactions within 30% error in the prediction of the ignition delay time and the mole fractions of major species in the propagating flame.

DOI： DOI: 10.1299/jtst.2016jtst0014

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To investigate the effect of the furnace scale on the heat transfer mechanism of coal particles, numerical simula- tions of coal combustion fields in three different scale furnaces (915 MWth actual large scale boiler, 2.4 MWth and 0.76 MWth test furnaces) were conducted. High accuracy of simulation methods was validated with the mea- sured data. From the comparison of numerical simulations between three different scale furnaces, it was clarified that the particle residence time with high particle temperature for a small scale furnace is shorter than that for a large scale furnace even if the particle residence time passing the high temperature gas is the same. This is caused by the insufficient heat gain of particles for a small scale furnace due to the lower radiation heat transfer because of the thinner flame thickness in the small furnace. The sphericity of ash particles from small scale furnaces is lower than that for large scale furnaces due to the shorter particle residence time with high particle temperature. These findings should be considered when the usability of coal brands for actual large scale boilers is evaluated by the fly ash properties from a small scale experimental furnace.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Rapid detection of coal and fly ash is significant to improve the efficiency of thermal power plants and reduce environmental pollution. Given its fast response, high sensitivity, real-time, and non- contact features, laser-induced breakdown spectroscopy (LIBS) has a great potential for on-line measurement in these applications. The direct measurement of particles and gases using LIBS was studied, and the method was shown to be effective for this application.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Compact schemes combined with compact filters are widely used for computational aeroacoustics. As compact filters require special treatment near the boundaries, near boundary filters were proposed by Visbal and Gaitonde (AIAA Paper, (1998)) and Gaitonde and Visbal (AIAA Journal, (2000)). However, these proposed near-boundary filter formulas have several drawbacks, the influence on computations of aerodynamic sound has not been uncovered. In this paper, we focus on the effects of these filters at the near-boundary points on the accurate calculation of aerodynamic sound generated by vortical flows near a wall. The results reveal that the appropriate filtering at the near-boundary nodes with no adverse impact on stability is essential to compute aerodynamic sound. The application of high-order boundary formulas such as 6th order boundary compact filtering is not appropriate because of an incorrect vortex motion and resultant spurious sound fields. A higher order boundary compact filter is not necessarily suitable for computations of aerodynamic sound due to its spectral function. In the case of using lower order centered filtering formulas approach, the value of a free parameter of the filter and the grid resolution have a serious influence on the computation of aerodynamic sound. Two appropriate filters at the near-boundary are presented.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A three-dimensional particle-laden two-phase direct numerical simulation by employing the Eulerian–Lagrangian method is performed to investigate effects of parcel modeling on characteristics of particles’ spatial dispersion, interphase mass and momentum transfers in a turbulent mixing layer. As the parcel models, two typical models such as the volume fixed model, VFM, in which each parcel has the same vol- ume and the number fixed model, NFM, in which each parcel represents the same number of particles are examined. The case without the parcel model is also performed to compare with the models as a refer- ence, RC. Results show that the parcel models significantly affect the particle dispersion, interphase mass and momentum transfers. It is found that NFM can qualitatively capture the trend of RC with small dis- crepancies, while VFM cannot reproduce it very much. The discrepancies become marked with increasing the number of particles represented by one parcel. The results suggest that the parcel models should be carefully treated with confirming the number of particles represented by one parcel in the entire range of particle size distribution.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A computational fluid dynamics (CFD) approach to simulate reacting flow in a hot coke oven gas (HCOG) reformer is presented. The HCOG was reformed by non-catalytic partial oxidation in a tubular reactor (0.6 m i.d. and

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

This paper reports a numerical investigation of the motion of spherical and non-spherical particles with/without gas blowing-out in a vertical uniform flow. A sphere, spheroid and pulverized coal particle are targeted in this study. The shape of coal particle is three-dimensionally modeled by scanning a coal particle using the X-ray CT method. As a first stage of the research, the Arbitrary Lagrangian-Eulerian (ALE) method is validated by comparing with the experiment. Secondly, the simulations of spherical and non-spherical particles with or without gas blowing-out in a vertical uniform flow are performed. The results show that the spheroidal particle with equivalent volume has a more similar accelerating motion to that of coal particle than spherical particle. For spheroidal particle, its distribution of PDF of CD shows a possibility to make a CD equation with Re and particle’s orientation. It is also revealed that the motion of coal particle with irregular shape is significantly dependent on its shape, especially with gas blowing-out. A new model in which this complex shape effects can be considered is required to describe the irregular shape particle.

DOI： 10.1299/transjsme.15-00068

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

In this paper, direct numerical simulations of the sound from vortex dipole rebound from an adiabatic non-slip wall are performed to investigate the impacts of the boundary schemes combined with the 6th order compact scheme on the capability of capturing the acoustic waves generated by vortical flows near a wall. The free parameter of the compact filter α=0.45 and α=0.49 are chosen to clarify effects of boundary schemes in high wave number region. Results show that some boundary schemes make the computations unstable and high order boundary schemes are not always appropriate. It is found that in the case of α=0.45, no remarkable difference is found in the results computed by each boundary scheme. On the other hand, in the case of α=0.49, the vorticity of vortex dipole almost does not depend on the each scheme. However, the vorticity of secondary vortex on the wall computed depends on the each boundary scheme and spatial resolution. This causes large difference in the distributions of vorticity and sound waves. It is therefore clearly understood that the characteristics of the first derivative of the boundary schemes combined with the 6th order compact scheme in the high wave number band affect the capability to precisely capture the aerodynamic sound. When the compact filter’s free parameter is chosen to be α=0.49, the boundary schemes have a strong influence on the computation of aerodynamic sound. Special attention to a combination of boundary and compact schemes is required to perform accurate computations of aerodynamic sound generated by flows near a wall.

DOI： 10.1299/transjsme.14-00544

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Three-dimensional direct numerical simulation is performed in a particle-laden turbulent mixing layer to investigate the effects of a parcel modeling on the charac- teristics of particle dispersion, scalar diffusion and velocity fluctuation. The effects of the parcel model are carefully investigated and discussed in comparison with the case in which the parcel model is not used as a reference, RC, in terms of the number of particles represented by a parcel, Np, and Stokes number defined by the particle relaxation time and Kolomogorov time scale, St. Results show that the parcel model can capture almost behavior of particle dispersion while the discrepancy between the model and RC becomes larger with increasing Np. The evaporation rate is sup- pressed by employing parcel model, because the vapor pressure in a cell is rapidly saturated by the parcel which represents a number of particles and subsequently the mass transfer number is underestimated. The trend of turbulence modulation is qualitatively captured by the cases employing the parcel model with the small Np while the case with the larger Np and St cannot capture the trend. It is therefore essential that Np and St are carefully determined to avoid capturing the nonphysical behavior in a numerical simulation with the parcel model.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A numerical approach is presented for predicting the species concentrations and temperature profiles of chemically reacting flow in the non-catalytic partial oxidation of hot coke oven gas (HCOG) in a pilot- scale reformer installed on an operating coke oven. A detailed chemical kinetic model consisting of 2216 reactions with 257 species ranging in size from the hydrogen radical to coronene was used to pre- dict the chemistries of HCOG reforming and was coupled with a plug model and one-dimensional (1D) flow with axial diffusion model. The HCOG was a multi-component gas mixture derived from coal dry distillation, and was approximated with more than 40 compounds: H2, CO, CO2, CH4, C2 hydrocarbons, H2O, aromatic hydrocarbons such as benzene and toluene, and polycyclic aromatic hydrocarbons up to coronene. The measured gas temperature profiles were reproduced successfully by solving the energy balance equation accounting for the heat change induced by chemical reactions and heat losses to the surroundings. The approach was evaluated critically by comparing the computed results with experimen- tal data for exit products such as H2, CO, CO2, and CH4, in addition to the total exit gas flow rate. The axial diffusion model slightly improves the predictions of H2, CO, and CO2, but significantly improves those of CH4 and total exit flow rate. The improvements in the model predictions were due primarily to the improved temperature predictions by accounting for axial diffusion in the flow model.

DOI： 10.1016/j.cej.2014.12.041

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Large-eddy simulation is applied to a laboratory-scale open-type pulverized coal flame generated by a triple stream burner, and the NO production and reduction in oxy-fuel condition are investigated for the first time. Pulverized Cerrejon coal which is classified as bituminous coal is used as a fuel. The results show that regardless of the equivalence ratio, as the O2 concentration increases from 21% to 40%, O2 consumption becomes marked because gas temperature rises and oxidation reaction is enhanced by the higher concentration of O2. Also, NO is formed rapidly due to the oxidation reaction of nitrogen from volatile matter of coal, and its concentration reaches a few hundred ppm further downstream. After the rapid formation, in the case of equivalence ratio larger than unity, NO decreases, because the reducing atmosphere becomes dominant due to the lack of O2. The trend becomes significant as the O2 concentra- tion in the carrier gas increases from 21% to 40%. In the case of equivalence ratio less than unity, on the other hand, NO does not decrease clearly, because the oxidizing atmosphere contributes to the further formation of NO. Present study shows the usefulness of the large-eddy simulations for predicting the characteristics of pulverized coal flames.

DOI： 10.1016/j.fuel.2014.10.069

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Partially sharing of active sites on char particle by multicomponent gasifying agent and detailed chemistry of water–gas-shift reaction are modeled and implemented. A three-dimensional RANS-based simulation with these models is also performed to investigate effects of a CO2 injection on gasification characteristics within an entrained flow coal gasifier. Results show that the gasification performance such as carbon conversion, product gas composition and gaseous temperature distribution is precisely cap- tured by the present simulation. The reaction inhibition by the product gas and the reaction suppression by the multicomponent gasifying agent’s partially sharing active sites are reasonably predicted. The effects of the CO2 injection on the gasification characteristics are also discussed in detail with considering contributions of reaction pathways to the gasification performance. It is revealed that it is essential to locally control exothermic gaseous reactions and endothermic heterogeneous reactions in order to take advantage of the CO2 injection.

DOI： 10.1016/j.fuel.2014.11.012

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

The char combustion/gasification reaction is one of the most important keys for obtaining an accurate prediction because the reaction is often the rate-limiting reaction in a system. However, it is often difficult to obtain a good agreement with measured conversion without making an adjustment of the model parameters for each intended furnace because of its great simplicity, although the original model parameters which are determined by fundamental experiments (e.g. thermogravimetric analysis and drop tube furnace) should be used for any furnace. In this paper, the char combustion model (H. Umetsu, et al. Combustion and Flame, 2014) was examined for two kinds of numerical simulation: (i) one-dimensional simulation in which the flow field is assumed to be a plug flow and (ii) three-dimensional simulation using LES for fluid and Lagrangian particle tracking. The char combustion model was validated using the char oxidation data obtained by a drop tube furnace. For 1D simulation, it was demonstrated that the model can precisely capture characteristics in the wide range of temperatures and stages of carbon conversion. For 3D simulation, the same values of the model parameters were used and it was found that a plug flow assumption was relatively valid for the rear section of the furnace but a non-negligible disturbance in flow field was observed around the injector owing to a large difference in velocity between that from the injector and bulk flow. Because of the disturbance, a high conversion was observed for the region near the injector compared with 1D simulation. However, lower conversions were observed for the rear section. This is obviously because of lower temperature of the gas on the central axis.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Characteristics of compact schemes combined with compact filters for compressible flows are numerically investigated on the Sod's problem in this study. Tridiagonal 6th, 8th and pentadiagonal 10th order compact schemes developed by Lele and 4th order compact scheme developed by Kim are used for the spatial derivatives and compact filters proposed by Lele, Gaitonde, Zhanxin, Kim are examined under CFL=1.0 condition. L1 and L2 norm are calculated from errors on velocity field from the end of expansion wave to shock. Results show that the compact filter developed by Gaitonde (free parameter is near 0.5) with Lele's 6th order compact scheme makes large error near the end of expansion wave and it cannot remove numerical oscillations perfectly near boundary. It is also revealed by the tests with Gaitonde's 8th order compact filter that the higher order compact scheme developed by Lele makes smaller L1 and L2 norms and the 4th order compact scheme developed by Kim makes the smallest L1 and L2 norm. In addition, it is found by the tests with Kim's 6th order compact filter that the higher order compact scheme developed by Lele makes smaller L1 and L2 norms and the 4th order compact scheme developed by Kim makes the smallest L1 and L2 norm. In all combinations of compact schemes and compact filters assessed in the present paper, although no combination of them can suppress spurious oscillations near the end of expansion wave and a shock perfectly, Kim's 4th order compact scheme combined with Kim's 6th order compact filter is the most appropriate to capture shock.

DOI： 10.1299/transjsme.2014fe0227

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The demands for lowering the burdens on the environment will continue to grow steadily. It is important to monitor controlling factors in order to improve the operation of industrial thermal systems. In engines, exhaust gas temperature and concentration distributions are important factors in nitrogen oxides (NOx), total hydrocarbon (THC) and particulate matter (PM) emissions. Coal and fly ash contents are parameters which can be used for the control of coal-fired thermal power plants. Monitoring of heavy metals such as Hg is also important for pollution control. In this study, the improved laser measurement techniques using computed tomography-tunable diode laser absorption spectroscopy (CT-TDLAS), low pressure laser-induced breakdown spectroscopy (LIBS), and laser breakdown time-of-flight mass spectrometry (LB-TOFMS) have been developed and applied to measure 2D temperature and species concentrations in engine exhausts, coal and fly ash contents, and trace species measurement. The 2D temperature and NH3 concentration distributions in engine exhausts were successfully measured using CT-TDLAS. The elemental contents of size-segregated particles were measured and the signal stability increased using LIBS with the temperature correction method. The detection limit of trace species measurement was enhanced using low pressure LIBS and LB-TOFMS. The detection limit of Hg can be enhanced to 3.5 ppb when employing N2 as the buffer gas using low pressure LIBS. Hg detection limit was about 0.82 ppb using 35 ps LB-TOFMS. Compared to conventional measurement methods laser diagnostics has high sensitivity, high response and non-contact features for actual industrial systems. With these engineering developments, transient phenomena such as start-ups in thermal systems can be evaluated to improve the efficiency of these thermal processes.

DOI： 10.1016/j.applthermaleng.2014.05.063

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The effects of ambient pressure on soot formation in spray jet flames are investigated by means of a two- dimensional direct numerical simulation (DNS). In addition, the effects of precursors on soot formation are also discussed. The inception models considering acetylene and polycyclic aromatic hydrocarbon (PAH) precursors are employed and compared in this study. The extended flamelet/progress-variable approach (EFPV) in which heat transfer between a droplet and the surrounding fluid can be considered is employed as a combustion model. Jet A is used as a liquid fuel with considering the detailed chemistry including 274 chemical species and 1537 elemental reactions by the flamelet library. The evaporating droplets’ motions are tracked by the Lagrangian method and the non-equilibrium Langmuir–Knudsen model is used as an evaporation model. Results show that the spray jet flame structure and the soot for- mation characteristics are considerably affected by the ambient pressure condition. The soot volume frac- tion increases with increasing the ambient pressure. It is also revealed that the dominant process to promote the soot formation is different between the acetylene and PAH precursor models. It is essential to model a soot inception process with appropriate precursors in order to understand a detail mechanism of soot formation, since the precursor which plays the important role depends on the type of fuel and the combustion conditions.

DOI： 10.1016/j.apt.2014.03.022

記述言語：英語   掲載種別：研究論文（学術雑誌）  

For understanding of film cooling flow fields on gas turbine blades, this paper reports on a series of large- eddy simulations of an inclined round jet issuing into a crossflow. Simulations were performed at four blowing ratios, BR = 0.1, 0.5, 0.7 and 1.0, and the Reynolds number, Re = 15,300, based on the crossflow velocity and film cooling hole diameter. Results showed that the cooling jet flow structure drastically changed with the blowing ratio. A pair of rear vortices and hairpin vortices were observed for BR = 0.1. A horseshoe vortex periodically ejected, a pair of hanging vortices, a pair of rear vortices and hairpin vor- tices were observed for BR = 0.5. Similar vortical structures to BR = 0.5 were observed for BR = 0.7 although horseshoe vortex was not ejected periodically and stayed at a leading edge of the hole exit. For BR = 1.0, in addition to the former mentioned vortices, shear layer vortices and vertical streaks were observed on an upstream edge of the jet. It was consequently understood that the ubiquitous counter- rotating vortex pair which can be observed in the time-averaged flow field was actually originated in the different vortical structures with varying BR conditions. Temperature fields were also investigated to clarify how these different vortical structures affect the film cooling effectiveness.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A char combustion model suitable for a large-scale boiler/gasifier simulation, which considers the variation of physical quantities in the radial direction of char particles, is developed and examined. The structural evolution within particles is formulated using the basic concept of the random pore model while simultaneously considering particle shrinkage. To reduce the computational cost, a new approximate analytical boundary condition is applied to the particle surface, which is approximately derived from the Stefan–Maxwell equations. The boundary condition showed reasonably good agreement with direct numerical integration with a fine grid resolution by the finite difference method under arbitrary conditions. The model was applied to combustion in a drop tube furnace and showed qualitatively good agreement with experiments, including for the burnout behavior in the late stages. It is revealed that the profiles of the oxygen mole fraction, conversion, and combustion rate have considerably different characteristics in small and large particles. This means that a model that considers one total conversion for each particle is insufficient to describe the state of particles. Since our char combustion model requires only one fitting parameter, which is determined from information on the internal geometry of char particles, it is useful for performing numerical simulations.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Large-eddy simulation (LES) is applied to turbulent spray combustion fields in a subscale (1/2) aircraft jet engine combustor with an air-blast type swirl fuel nozzle and validity is examined by comparing with measurements. In the LES, Jet-A is used as liquid fuel, and individual droplet motion is tracked in a Lagrangian manner with a parcel model. As a turbulent combustion model, the extended flamelet/progress-variable approach, in which heat transfer between droplets and ambient gas including radiation and heat loss from walls can be taken into account, is employed. A detailed chemistry mechanism of Jet-A with 1537 reactions and 274 chemical species is used. The radiative heat transfer is com- puted by the discrete ordinate (DO) method. The equivalence ratio ranges from 0.91 to 1.29. The comparisons of the predicted droplet velocity and size, gaseous temperature, NO, and soot emissions with the measurements show that the present LES is capable of capturing the general features of the turbulent spray combustion fields in the subscale (1/2) aircraft jet engine combustor.

DOI： 10.1115/1.4024868

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

A two-dimensional direct numerical simulation is performed in a particle-laden turbulent flow to investigate effects of a parcel modeling on characteristics of par- ticles’ dispersion, fluctuation velocity of ambient turbulence and scalar diffusion in a turbulent mixing layer. Two parcel models in which each parcel has the same volume (volume fixed model, VFM) and represents the same number of particles (number fixed model, NFM) are discussed by comparing with directly tracking one by one particle without a parcel model as a referred case (reference case, RC). In consequence of the simulation, the spatial distribution of the dispersed particles for NFM shows a good agreement in comparing with RC. While spatially skewed dis- tribution appeared for VFM. Fluctuation velocity distribution is overestimated for both VFM and NFM in comparing with RC as the number of particle represented by one parcel is increased and subsequently scalar diffusion is overestimated in present numerical conditions.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In order to simulate coal combustion and develop optimal and stable boiler control systems in real power plants, it is imperative to obtain the detailed information in coal combustion processes as well as to measure species contents in fly ash, which should be controlled and analyzed for enhancing boiler efficiency and reducing envi- ronmental pollution. The fly ash consists of oxides (SiO2, Al2O3, Fe2O3, CaO, and so on), unburned carbon, and other minor elements. Recently laser-induced breakdown spectroscopy (LIBS) technique has been applied to coal combustion and other industrial fields because of the fast response, high sensitivity, real-time and non-contact features. In these applications it is important to measure controlling factors without any sample preparation to maintain the real-time measurement feature. The relation between particle content and particle diameter is also one of the vital researches, because compositions of particles are dependent on their diameter. In this study, we have detected the contents of size-segregated particles using LIBS. Particles were classified by an Anderson cascade impactor and their contents were measured using the output of 1064 nm YAG laser, a spectro- graph and an ICCD camera. The plasma conditions such as plasma temperature are dependent on the size of particles and these effects must be corrected to obtain quantitative information. The plasma temperature was corrected by the emission intensity ratio from the same atom. Using this correction method, the contents of particles can be measured quantitatively in fixed experimental parameters. This method was applied to coal and fly ash from a coal-fired burner to measure unburned carbon and other contents according to the particle diameter. The acquired results demonstrate that the LIBS technique is applicable to measure size-segregated particle contents in real time and this method is useful for the analysis of coal combustion and its control because of its sensitive and fast analysis features.

DOI： 10.1016/j.sab.2013.05.034

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Soot formation characteristics of a lab-scale pulverized coal flame were investigated by performing care- fully controlled laser diagnostics. The spatial distributions of soot volume fraction and the pulverized coal particles were measured simultaneously by laser induced incandescence (LII) and Mie scattering imaging, respectively. In addition, the radial distributions of the soot volume fraction were compared with the OH radical fluorescence, gas temperature and oxygen concentration obtained in our previous studies [1,2]. The results indicated that the laser pulse fluence used for LII measurement should be carefully controlled to measure the soot volume fraction in pulverized coal flames. To precisely measure the soot volume fraction in pulverized coal flames using LII, it is necessary to adjust the laser pulse fluence so that it is sufficiently high to heat up all the soot particles to the sublimation temperature but also sufficiently low to avoid including a too large of a change in the morphology of the soot particles and the superposition of the LII signal from the pulverized coal particles on that from the soot particles. It was also found that the radial position of the peak LII signal intensity was located between the positions of the peak Mie scattering signal intensity and peak OH radical signal intensity. The region, in which LII signal, OH radical fluores- cence and Mie scattering coexisted, expanded with increasing height above the burner port. It was also found that the soot formation in pulverized coal flames was enhanced at locations where the conditions of high temperature, low oxygen concentration and the existence of pulverized coal particles were satisfied simultaneously.

DOI： 10.1016/j.proci.2012.10.002

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

A two-dimensional direct numerical simulation is applied to spray jet flames, and effects of background pressure and droplet size on soot formation behavior is investigated in detail in the mono-dispersed droplet size conditions. N-decane (C10H22) is used as a liquid fuel, and droplet motion is calculated by the Lagrangian method. The extended flamelet/progress-variable approach is emplyed for the turbulent combustion chemistry. A kinetically based soot formation model with the flamelet model is employed to predict soot formation. The results show that the soot is mainly formed in the large vortex structure in the downstream region and the soot formation behavior is significantly affected by the pressure. It is found that the soot volume fraction and soot particle diameter increases with increasing the pressure due to that the concentration of soot precursor increases and the soot particles' residence time is enlongated in the structure.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The effects of equivalence ratio, fuel droplet size, and radiation on jet spray flame are investigated by means of two-dimensional direct numerical simulation (DNS). In addition, the validity of an extended flamelet/progress-variable approach (EFPV), in which heat transfer between droplets and ambient fluid including radiation is exactly taken into account, is examined. n-decane (C10H22) is used as liquid spray fuel, and the evaporating droplets’ motions are tracked by the Lagrangian method. The radiative heat transfer is calculated using the discrete ordinate method with S8 quadrature approximation. The results show that the behavior of jet spray flame is strongly affected by equivalence ratio and fuel droplet size. The general behavior of the jet spray flames including the heat transfer between droplets and ambient fluid with radiation effect can be captured by EFPV.

DOI： 10.1016/j.fuel.2012.08.044

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

A two-dimensional numerical simulation is applied to spray jet flames, and effect of droplet size on soot formation behavior is investigated in detail in the mono- and poly-dispersed droplet size conditions. N-decane(C10H22) is used as a liquid fuel, and droplet motion is calculated by the Lagrangian method. The extended flamelet/progress-variable approach is employed for the turbulent combustion chem- istry. A kinetically based soot formation model with flamelet model is employed to predict soot formation. Radiation is taken into account using the discrete ordinate method. The results show that the soot is mainly formed in the large vortex struc- ture in the downstream region and the soot formation behavior is strongly affected by the droplet size. The soot volume fraction increases with increasing the mono- dispersed droplet size, and the larger droplet in the widely-distributed condition affects the soot formation behavior.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

For understanding of film cooling flow fields on a gas turbine blade, this paper reports on a series of large-eddy simulations of an inclined round jet issuing into a crossflow. Simulations were performed at four blowing ratio conditions, BR=0.1, 0.5, 0.7 and 1.0 and Reynolds number, Re=15,300, based on crossflow velocity and film cooling hole diameter. Results showed that cooling jet flow structure drastically changed with blowing ratio. A pair of rear vortex and hairpin vortex were observed for BR=0.1. A periodic ejection of horseshoe vortex, a pair of hanging vortex, a pair of rear vortex and hairpin vortex were observed for BR=0.5. Similar vortical structures to BR=0.5 were observed for BR=0.7 although horseshoe vortex remained at a leading edge of the hole exit. For BR=1.0, in addition to the former mentioned vortices, spanwise rollers and vertical streaks were observed on an upstream edge of the jet. It was, consequently understood that the ubiquitous counter-rotating vortex pair which can be defined in the time-averaged flow field was actually originated in the different vortical structures with varying BR conditions.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The effects of fuel droplet size on soot formation in spray flames formed in a laminar counterflow are investigated experimentally and numerically. Sauter mean diameter (SMD) of quasi-monodispersed fuel spray (n-decane) is carefully controlled independently from the other spray characteristics using a fre- quency-tunable vibratory orifice atomizer, and the two-dimensional spatial distributions of soot volume fraction and soot particle size are measured by laser induced incandescence (LII) and time resolved LII (TIRE-LII), respectively. In addition, the soot formation processes are examined in detail by a two-dimen- sional direct numerical simulation (DNS) employing a kinetically based soot model with flamelet model. The results show that the soot formation area and location are strongly affected by the SMD of the fuel spray. As the SMD of the fuel spray increases, the average soot formation area expands, whereas local suppression of soot formation is instantaneously observed in the spray flames because of the appearance of groups of unburned droplets. The size of soot particles tend to be larger in the outer part of the soot formation area compared to soot in the inner part. This is because the surface growth of soot particles markedly proceeds compared to the coagulation and oxidation.

DOI： 10.1016/j.combustflame.2011.05.015

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.egypro.2011.01.156

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Negative Magnus lift acting on a sphere rotating about the axis perpendicular to an incoming flow is investigated using large-eddy simulation at three Reynolds numbers of 1.0×104, 2.0 × 105, and 1.14 × 106. The numerical methods adopted are first validated on a non-rotating sphere and the spatial resolution around the sphere is determined so as to reproduce the laminar separation, reattachment, and turbulent transition of the boundary layer observed at around the critical Reynolds number. In the rotating sphere, positive or negative Magnus effect is observed depending on the Reynolds number and the rotating speed imposed. At the Reynolds number in the subcritical or supercritical region, the direction of the lift force follows the Magnus effect to be independent of the rotational speed tested here. In contrast, negative lift is observed at the Reynolds number at the critical region when particular rotating speeds are imposed. The negative Magnus effect is discussed in the context of the suppression or promotion of boundary layer transition around the separation point.

DOI： 10.1088/1742-6596/318/3/032021

記述言語：英語   掲載種別：研究論文（学術雑誌）  

An experimental study of counter-current annular two-phase flow of high-viscosity liquid and air in a large diameter pipe was carried out to investigate the inception criterion for entrainment of molten slag droplet in an entrained flow coal gasifier. Liquid film thickness was measured using a high-speed camera for 4 types of liquid with various viscosities and surface tensions. It was clearly shown that the measured average wave amplitude had a good correlation with the gas Reynolds number, and that the predicted critical gas velocity for droplet inception using new formula of wave amplitude had a good agreement with the experimental results under the condition of very low fluid Reynolds number( Ref ≤10). The critical Weber number Wec =1.73 was obtained as inception criterion of droplet entrainment.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Coal is an important energy resource for meeting the further demand for electricity, as coal reserves are much more abundant than those of other fossil fuels. In pulverized coal fired power plants, it is very important to improve the technology for the control of environmental pollutants such as NOx, SOx and ash particles including unburned carbon. With the remarkable progress in the performance of computers, it is strongly expected that the computational fluid dynamics (CFD) would be a tool for the development and design of such suitable combustion furnaces and burners for the pulverized coal combustion. The focus of this review is to highlight our recent progress of CFD of the pulverized coal combustion in terms of Reynolds-Averaged Navier-Stokes (RANS) simulation and Large-Eddy Simulation (LES) together with some of future perspectives.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

A two-dimensional numerical simulation is applied to spray flames formed in a laminar counterflow, and effect of droplet size on soot formation behavior is inves- tigated in detail. N-decane(C10H22) is used as a liquid fuel, and droplet motion is calculated by the Lagrangian method. A one-step global reaction is employed for the combustion heat release. A kinetically based soot formation model with flamelet model is employed to predict soot formation. Radiation is taken into ac- count using the discrete ordinate method. The results show that the diffusion and premixed combustion co-exist in the spray flame and the soot is mainly formed in the spray diffusion flame region. The soot formation behavior is strongly affected by the droplet size. The soot volume fraction increases with increasing the droplet size.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

LES (Large-eddy simulation) of swirling cold-flows in a pulverized coal combustion furnace is performed and validated by comparing with experiment and RANS (Reynolds-Averaged Navier-Stokes) simulation with the standard k-ε model. Unstructured grids and energy-conserving scheme are employed to obtain robust and accurate solutions at high swirl numbers. The results show that the LES is in good agreement with the experiment in terms of the recirculation flow, though the RANS simulation overestimates it. This is considered due to the capability of prediction of turbulent mixing. The effect of secondary and tertiary swirler vanes' angles on the behavior of the recirculation flow are also well predicted by the LES. The recirculation flow affects the flame stabilization and combustion efficiency related to the particle residence time in the furnace. It can be said, therefore, that the LES is strongly recommended for the accurate prediction of the strong swirling flows in such furnaces.

DOI： 10.1299/jee.4.1

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

It is important to improve efficiency and to maintain stable operation of a coal gasifier in a commercial use of IGCC. In this paper, an optimization system for gasifier operating conditions which diagnoses an operation status via processes of online data and image of slag flow is described. It is confirmed that the system presented here is useful to assess the gasification condition in the verification using CRIEPI's research gasifier“FRONTIA”.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Two-dimensional numerical simulations are applied to spray flames formed in a laminar counterflow and the effects of radiation on spray flame characteristics and soot formation are studied. N-Decane (C10H22) is used as the liquid fuel, and the droplet motion is calculated by the Lagrangian method. A single-step global reaction is employed for the combustion reaction model. A kinetically based soot model with a flamelet model is used to predict soot formation. Radiation is taken into account using the discrete ordinate method. The results show that radiation strongly affects the spray flame behavior and soot formation. Without the radiation model, flame temperature and soot volume fraction are greatly overestimated. The soot is formed in the diffusion flame regime, and its radiation emission increases with the increase in the equivalence ratio of the droplet fuel. This trend is in good agreement with that of the luminous flame behavior observed in the experiments.

DOI： 10.1016/j.combustflame.2007.07.021

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A two-dimensional numerical simulation of a spray flame formed in a laminar counterflow is presented, and the flamelet characteristics are studied in detail. The effects of strain rate, equivalence ratio, and droplet size are examined in terms of mixture fraction and scalar dissipation rate. n-Decane (C10H22) is used as a liquid spray fuel, and the droplet motion is calculated by the Lagrangian method without the parcel model. A one-step global reaction is employed for the combustion reaction model. The results show that there appear large differences in the trends of gaseous temperature and mass fractions of chemical species in the mixture fraction space between the spray flame and the gaseous diffusion flame. The gas temperature in the spray flame is much higher than that in the gaseous diffusion flame. This is due to the much lower scalar dissipation rate and the coexistence of premixed and diffusion-limited combustion in the spray flame. For the spray flames, gas temperature and mass fractions of chemical species are not unique functions of the mixture fraction scalar dissipation rate. This is because the production rate of the mixture fraction, namely evaporation rate of the droplets, in the upstream region is not in proportion to its transport-diffusion rate in the downstream region. The behavior shows marked differences as the strain rate decreases, the equivalence ratio increases, or the droplet size decreases.

DOI： 10.1016/j.combustflame.2006.09.006

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This paper presents modeling of a coal gasification reaction, and prediction of gasification performance for an entrained flow coal gasifier. The purposes of this study are to develop an evaluation technique for design and performance optimization of coal gasifiers using a numerical simulation technique, and to confirm the validity of the model. The coal gasification model suggested in this paper is composed of a pyrolysis model, char gasification model, and gas phase reaction model. A numerical simulation with the coal gasification model is performed on the CRIEPI 2 tons/day (T/D) research scale coal gasifier. Influence of the air ratio on gasification performance, such as a per pass carbon conversion efficiency, amount of product char, a heating value of the product gas, and cold gas efficiency is presented with regard to the 2 T/D gasifier. Gas temperature distribution and product gas composition are also presented. A comparison between the calculation and experimental data shows that most features of the gasification performance were identified accurately by the numerical simulation, confirming the validity of the current model.

DOI： 10.1016/j.fuel.2006.02.002

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

開催年月日： 2023年11月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：九州大学筑紫キャンパス   国名：日本国  

開催年月日： 2023年11月

記述言語：日本語  

開催地：九州大学筑紫キャンパス   国名：日本国  

開催年月日： 2023年10月

記述言語：英語  

開催地：福井県国際交流会館   国名：日本国  

開催年月日： 2023年8月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：福岡大学   国名：日本国  

開催年月日： 2023年8月

記述言語：英語  

開催地：Tokyo   国名：日本国  

開催年月日： 2023年5月

記述言語：英語  

開催地：福岡国際会議場   国名：日本国  

開催年月日： 2023年5月

記述言語：日本語  

開催地：福岡国際会議場   国名：日本国  

開催年月日： 2023年5月

記述言語：英語  

開催地：Kyoto International Conference Center   国名：日本国  

開催年月日： 2022年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Online   国名：アメリカ合衆国  

開催年月日： 2022年11月

記述言語：英語  

開催地：東京   国名：日本国  

開催年月日： 2022年11月

記述言語：英語  

開催地：熊本   国名：日本国  

開催年月日： 2022年11月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催地：釜山   国名：大韓民国  

開催年月日： 2022年10月

記述言語：日本語  

開催地：福岡   国名：日本国  

開催年月日： 2022年9月

記述言語：英語  

開催地：名古屋   国名：日本国  

開催年月日： 2021年12月

記述言語：英語  

開催地：オンライン   国名：アメリカ合衆国  

開催年月日： 2021年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年11月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年10月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年7月 - 2022年7月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2020年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2020年10月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2019年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Maui, Hawaii   国名：アメリカ合衆国  

開催年月日： 2019年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Maui, Hawaii   国名：アメリカ合衆国  

開催年月日： 2019年12月

記述言語：英語  

開催地：San Francisco   国名：アメリカ合衆国  

開催年月日： 2019年12月

記述言語：英語  

開催地：San Francisco   国名：アメリカ合衆国  

開催年月日： 2019年12月

記述言語：英語  

開催地：San Francisco   国名：アメリカ合衆国  

開催年月日： 2019年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Xi'an   国名：中華人民共和国  

開催年月日： 2019年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Xi'an   国名：中華人民共和国  

開催年月日： 2019年11月

記述言語：英語  

開催地：札幌   国名：日本国  

開催年月日： 2019年11月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Jeju   国名：大韓民国  

開催年月日： 2019年11月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Sendai   国名：日本国  

開催年月日： 2019年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：名古屋   国名：日本国  

開催年月日： 2019年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：函館   国名：日本国  

開催年月日： 2019年7月 - 2019年8月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：San Francisco   国名：アメリカ合衆国  

開催年月日： 2019年7月 - 2019年8月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：San Francisco   国名：アメリカ合衆国  

開催年月日： 2019年7月 - 2019年8月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：San Francisco   国名：アメリカ合衆国  

開催年月日： 2019年7月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Fukuoka   国名：日本国  

開催年月日： 2019年5月

記述言語：英語  

開催地：福岡   国名：日本国  

開催年月日： 2019年5月

記述言語：英語  

開催地：福岡   国名：日本国  

開催年月日： 2019年5月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Aachen   国名：ドイツ連邦共和国  

開催年月日： 2019年4月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Vienna   国名：オーストリア共和国  

開催年月日： 2018年12月

記述言語：英語  

開催地：機械振興会館   国名：日本国  

開催年月日： 2018年11月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：堺市産業振興センター   国名：日本国  

開催年月日： 2018年9月

記述言語：英語  

開催地：明治大学駿河台キャンパス   国名：日本国  

開催年月日： 2018年7月 - 2018年8月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：The Convention Centre Dublin   国名：アイルランド  

開催年月日： 2018年7月 - 2018年8月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：The Convention Centre Dublin   国名：アイルランド  

開催年月日： 2018年5月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：横浜   国名：日本国  

開催年月日： 2017年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：福岡   国名：日本国  

開催年月日： 2017年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：富山   国名：日本国  

開催年月日： 2017年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：富山   国名：日本国  

開催年月日： 2017年11月

記述言語：英語  

開催地：Yeosu   国名：大韓民国  

開催年月日： 2017年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：つくば   国名：日本国  

開催年月日： 2017年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪   国名：日本国  

開催年月日： 2017年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪   国名：日本国  

開催年月日： 2017年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪   国名：日本国  

開催年月日： 2017年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪   国名：日本国  

開催年月日： 2017年6月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年5月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：早稲田大学国際会議場   国名：日本国  

開催年月日： 2017年3月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Jeju Island   国名：大韓民国  

In the field of pulverized coal combustion, the development of the combustion technology meeting the demands such as reducing environmental pollutants has been conducted by many researchers and developers. To make a further improvement, an understanding of the flow field and pulverized coal particle behaviors in the combustion furnace is necessary. However, it is difficult to obtain such information solely on the basis of experiments. In this study, large-eddy simulation (LES) is applied to the multi-burner pulverized coal combustion furnace and the effects of an in-furnace blending method, in which different kinds of coal (high volatile coal and low volatile coal) are injected at each burner stage, on NOx emission and unburned carbon concentration in fly ash are investigated. The blending ratio of high volatile coal is fixed at 33%. The variable density, low-Mach number, reacting flow equations with two-way coupling between gas phase and pulverized coal particles are solved using an unstructured LES solver, FrontFlow/Red extended by Kyoto University, Central Research Institute of Electric Power Industry and Numerical Flow Designing, Ltd. Result shows that oxygen is rapidly consumed near the burner, from which the low volatile coal is injected, and NOx decreases because the reducing atmosphere becomes dominant due to the lack of oxygen. These information on the effects of in-furnace blending method on the flow field that are considered to be essential for prediction of the product gases in the furnace, can only be captured in large scale unsteady simulation like present study.

開催年月日： 2016年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：タワーホール船堀   国名：日本国  

開催年月日： 2016年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東京大学生産技術研究所   国名：日本国  

開催年月日： 2016年11月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Melbourne   国名：オーストラリア連邦  

開催年月日： 2016年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：仙台国際センター   国名：日本国  

開催年月日： 2016年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：仙台国際センター   国名：日本国  

開催年月日： 2016年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：仙台国際センター   国名：日本国  

開催年月日： 2016年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福山市生涯学習プラザ   国名：日本国  

This paper reports a numerical simulation of coal devolatilization behavior. The new Extended-CPD Model which can predict the composition of light gas and tar volatilized by coal particles is introduced into the simulation and coupled with a detailed gaseous phase chemistry. DTF experiments in CRIEPI is targeted. N2=100% and a N2/O2=99.5%/0.5%, totally 2 conditions are performed. Results show that in 2 conditions the behavior of PAHs are quite different. It is confirmed that the numerical method used in this paper can capture the C, H, O composition in particles, also the PAH concentration and reacting rate distribution in gas phase qualitatively.

開催年月日： 2016年8月

記述言語：英語  

開催地：COEX, Seoul   国名：大韓民国  

CO-rich gasified fuel and oxygen with CO2-rich diluent is assumed to be burned at near stoichiometric condition in a gas turbine combustor of an oxy-fuel IGCC system. To investigate the fundamental combustion characteristics of such the CO-rich gasified fuel at near stoichiometric condition, large eddy simulations of a combustion on an atmospheric test combustor were performed. The test combustor operated by Central Research Institute of Electric Power Industry (CRIEPI), in which a small diffusion burner with separate fuel, oxidizer and diluent supply nozzles was employed. The combustor is a water-cooled combustor made of steel with refractory materials placed inside wall. The computational domain was designed to match the actual configuration of the burner. Numerical simulations employing one-step global reaction mechanism and employing two step reaction mechanism that considers CO2 dissociation reaction were performed. Both numerical simulation results were compared with the experimental results. The comparison reveals that the numerical simulation employing two-step reaction mechanism can reproduce the tendency of CO mole fraction distribution inside the combustor. On the other hand, the numerical simulation employing one-step global reaction mechanism could not predict the tendency of CO mole fraction distribution very much. Consideration of CO2 dissociation reaction is essential to predict the CO mole fraction in the CO-rich gasified fuel combustion field.

開催年月日： 2016年8月

記述言語：英語  

開催地：COEX, Seoul   国名：大韓民国  

In a numerical simulation of a diluted gas-particle two-phase reacting flow such as spray and coal combustion or gasification, the Eulerian-Lagrangian manner with the PSI-CELL method is generally employed to capture the motions of a number of particles with reducing the computational cost. However how this assumption affects the accuracy on the particle’s motion and ignition are rarely discussed. In this study, a direct numerical simulation (DNS) of the ignition of a single particle freely moving in a uniform flow to investigate the particle's motion and ignition behavior in detail. The Arbitrary Lagrangian-Eulerian (ALE) method is employed to compute the six-degree freedom computation of the particle's motion. The computational setting follows the experiment by Lee and Choi. The volatiles gas that is composed of CH4 and CO blows out at the particle surface and its velocity is set to 1.0 m/s and its direction is set perpendicular to particle surface. The ignition behavior is compared with that observed in the experiment. The effect of the particle's shape is also discussed. Results show that the long tail flame is formed after the particle released and as the particle accelerating, the tail flame becomes shorter and burning velocity becomes gently larger. This behavior is in good agreement with that in the experiment. While the slip velocity between the particle and the uniform flow becomes smaller than a certain threshold value, the burning velocity of the volatiles suddenly becomes large and finally a spherical flame is formed around the particle. After the spherical flame is formed, the burning velocity decreases again and then the flame becomes stable. It is found that this behavior can be understood by considering the variation of a strain rate (or scalar dissipation rate) between the volatiles jet and the surrounding gas flows. It is also revealed that the particles' shape dose not affect the ignition behavior very much.

開催年月日： 2016年8月

記述言語：英語  

開催地：COEX, Seoul   国名：大韓民国  

A numerical simulation was performed to investigate formation and decomposition behavior of polycyclic aromatic hydrocarbon (PAH) species in a pulverized coal jet flame by means of large eddy simulation (LES). For a gas phase kinetic, a skeletal mechanism derived from a detailed mechanism that includes a kinetic mechanism high carbonaceous species, up to C30, is employed in this study. In the devolatilization process, kinetic parameters for the release rate equation and the gas composition are determined by the FLASHCAHIN model. For a solid phase, a two-step simple reaction is implemented. The governing equations for the continuous phase are solved by means of LES. Coal particles are traced in the Lagrangian method individually with the parcel model. Heat, mass and momentum interactions between the continuous and dispersed phases are calculated based on the Particle-Source-In Cell model. The numerical simulation is performed by FrontFlowRed-Comb. Particle distribution and velocities are compared to the experiment according to the axial distance and the radial distance at specific heights to see the flow field, and the simulation results show good agreement. Particles are more dispersed in the non-combustion case comparing to the combustion case because the pilot flame and volatile matter combustion make the flow stream fast and it becomes laminar flow shape. The calculated temperature chemical reactions is compared to flame temperature measured by two-color pyrometer. The simulation result is much lower than the measured one at the upstream flow region, but they are similar at the flame region. From this result, it is found that chemical reactions implemented in this calculation describe coal flame reactions well. In the result of mole fraction profiles of PAH species, it is found that devolatilized matters are located following an intersection of inner air flow and a hot reaction zone and their position is a little outside of lite volatiles. This is exactly same result of the previous research presented by Hayashi. This means that the large devolatilized species move to outside of inner-cold flow and put in high temperature and low oxygen concentration. This is a favorable environment for polymerization of species and it is easy to promote soot growth.

開催年月日： 2016年6月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Creta Maris Conference Center, Crete Island   国名：ギリシャ共和国  

Large-eddy simulation of coal gasification on a two-stage entrained flow coal gasi- fier was performed to demonstrate the applicability of LES to coal gasification field. The La- grangian method is used to compute particle motions and dynamic SGS model is used as a turbulent model. The CRIEPI 2 tons/day research gasifier “FRONTIA” is targeted in this study and the results are compared to validate the numerical procedure. Results show that the gasification performance such as temperature, major chemical species were qualitatively in agreement with the experiment. It is also found that the strong swirl flow formed in the bottom part of gasifier plays an important role for mixing of dispersed particles with oxidizers to promote the endothermic gasification reactions. The LES is well demonstrated to capture the general feature of the coal gasification field in the two-stage entrained flow coal gasifier.

開催年月日： 2016年6月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Creta Maris' Conference Center, Crete Island   国名：ギリシャ共和国  

In the field of pulverized coal combustion, the development of the combustion technol- ogy meeting the demands such as reducing environmental pollutants has been conducted by many researchers and developers. To make a further improvement, an understanding of the flow field and pulverized coal particle behaviors in the combustion furnace is necessary. However, it is difficult to obtain such information solely on the ba- sis of experiments. Therefore numerical simulations has been applied to pulverized coal combustion fields in a single-burner furnace and recently, an effect of fuel ratio of coal is also investigated by blending different type of coal in the furnace. While utility multi-burner furnaces have been investigated mainly using Reynolds-Averaged Navier- Stokes Simulation, recent development of computational resources and techniques gradually enable us to conduct large-eddy simulation (LES) of unsteady combustion phe- nomena in such furnaces. In this study, LES is applied to the multi-burner pulverized coal combustion furnace shown in left side of the figure and an effect of fuel ratio of coal is investigated. The computational domain is divided in about 102 million cells and about 22 million vertexes. The variable density, low-Mach number, reacting flow equations with two-way coupling between gas phase and pulverized coal particles are solved using an un- structured LES solver, FrontFlow/Red extended by Kyoto University, Central Research Institute of Electric Power Industry and Numerical Flow Designing, Ltd. Results show that the effect of fuel ratio of coal on the flow field that are considered to be essential for prediction of the product gases such as nitrogen oxide in the furnace, can only be captured in large scale unsteady simulation like present study.

開催年月日： 2016年5月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：グランキューブ大阪(大阪府立国際会議場)   国名：日本国  

The effects of Sauter mean diameter (SMD) and droplet size distribution (DSD) on soot formed in the n-decane spray flame stabilized in a laminar counterflow field are investigated experimentally and numerically. Results show that the soot formation area is strongly affected by the SMD and DSD of the fuel spray. As the SMD of the fuel spray increases, the average soot formation area expands, whereas local suppression of soot formation is observed in the spray flames because of the evaporation of unburned droplets. The larger size of soot primary particles distributes in the outer part of the soot formation area of the spray flame. This is because the surface growth of soot particles markedly proceeds compared to the coagulation and oxidation.

開催年月日： 2016年5月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：グランキューブ大阪(大阪府立国際会議場)   国名：日本国  

Two dimensional distribution of coal particles, polycyclic aromatic hydrocarbons (PAHs) and soot volume fraction in a lab-scale pulverized coal flame were measured by performing laser diagnostics to elucidate the soot formation processes in pulverized coal jet flame. Results show that whereas the instantaneous spatial distribution of coal particles, PAHs and soot are different, time-averaged distribution of those signals covered each other. The radial distribution of signals of coal, PAHs and soot expanded with increasing the height from the burner port.

開催年月日： 2016年3月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Waikoloa Beach Marriott Resort & Spa, Hawaii's Big Island   国名：アメリカ合衆国  

開催年月日： 2016年3月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Waikoloa Beach Marriott Resort & Spa, Hawaii's Big Island   国名：アメリカ合衆国  

開催年月日： 2016年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：函館工業高等専門学校   国名：日本国  

開催年月日： 2015年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：福岡県春日市，九州大学（筑紫キャンパス）   国名：日本国  

開催年月日： 2015年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡市，九州大学（筑紫キャンパス）   国名：日本国  

開催年月日： 2015年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：名古屋大学   国名：日本国  

開催年月日： 2015年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：つくば国際会議場   国名：日本国  

Applicability of a flamelet model to a 3-feed non-premixed flame which is typically observed in the oxy-fuel IGCC system was numerically investigated in this study. Computations of flamelet equations for three model methodologies, 1D flamelet interpolation (1DINT), quasi-2D flamelet (Q2DFL) and 2D flamelet (2DFL), were performed and 1DINT and Q2DFL were compared with 2DFL that could be regarded as a reference. Results showed that by comparing the distributions of gas temperature and mass fraction of H2O for 2DFL, the large discrepancies appeared for 1DINT, while little difference was shown for Q2DFL. It was revealed that 1DINT cannot capture the characteristics of variables in the 2D flamelet space and Q2DFL is a good candidate to precisely generate the 2D flamelet library.

開催年月日： 2015年11月

記述言語：日本語  

開催地：つくば国際会議場   国名：日本国  

Two dimensional (2D) temperature distribution plays an important role for the combustion structure and the combustor efficiency. Recently, as a multi-species measurement technique with high sensitivity and high response, tunable diode laser spectroscopy (TDLAS) has been developed and applied to the actual combustors. Conventionally a thermocouple has been widely used as a temperature measurement device. However it is intrinsically a point measurement method and it is difficult to measure gas temperature distribution inside the combustion chamber. The computed tomography tunable diode laser spectroscopy (CT-TDLAS) method was employed in a pulverized coal flame burner to measure 2D temperature distribution. Absorption spectra of water vapour at 1388nm and 1343nm in the pulverized coal flame were measured by the CT-TDLAS method to evaluate quantitative measurements of temperature. This paper discusses evaluation of 2D temperature distribution measurement in the pulverized coal flame measured by CT-TDLAS.

開催年月日： 2015年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：つくば国際会議場   国名：日本国  

In this study, time-series measurement of 2-dimensional temperature distribution is carried out to investigate pulverized coal combustion phenomena. The temperature distribution is measured by computed tomography-tunable diode laser absorption spectroscopy (CT-TDLAS). Temperature measurement using TDLAS involves measuring the H2O absorption spectrum with tunable diode laser because the absorption spectrum changes with temperature. 1-path TDLAS measures average temperature in the laser beam path. CT-TDLAS in this study uses CT algorithm of 32-path laser beams to measure 2-dimensional temperature distribution. Results show that CT-TDLAS is able to be applied to measure 2-dimensional temperature distribution in pulverized coal combustion field which has a lot of dust. The temperature and the relative standard deviation of temperature increase with the increase in coal feed rate and air flow rate. CT-TDLAS is able to detect the time variation of 2-dimensional temperature distribution.

開催年月日： 2015年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：北海道大学   国名：日本国  

A large-eddy simulation of a coal gasification two-phase reacting flow on an entrained two-stage coal gasifier was performed to demonstrate the applicability of LES to this reacting field on the massively parallel computing on K computer. The CRIEPI’s 2.4 tons/day research gasifier was targeted. Results show that the strong swirl flows are formed within the combutor of the gasifier. The large part of particles traveling in the combustor should be expected to be captured by the centrifugal force and the characteristics is essential to optimize the gaisifer’s design and operating conditions. It is confirmed that the LES is a potentially powerful tool to predict the strong swirl reacting flows within the entrained flow gasifier.

開催年月日： 2015年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：北海道大学   国名：日本国  

Recently, noise reduction of energy equipment is needed. Especially, aerodynamic noise generated by flows near a solid object like a wall is important. Surface shear stress fluctuation is generated by flows near a solid object. Surface shear-stress fluctuation was found to be a source of aerodynamic sound by Shariff and Wang (2005). But an influence of surface shear stress in general flow on aerodynamic sound has not been uncovered. We focused on the time evolution of surface shear-stress caused by vortex pair colliding with a non-slip wall. It is revealed that surface shear-stress fluctuation is influenced by secondary vortex on the wall very much. An absolute value of surface shear-stress is increased when a vortex pair approaches the wall because of an increase of vorticity of secondary vortex. After, an absolute value of surface shear-stress is decreased and the position of maximum value of surface shear stress is changed because the vortex pair is separated with secondary vortex. This surface shear-stress fluctuation mechanism might be a one of the sound source.

開催年月日： 2015年7月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Kurashiki Royal Art Hotel   国名：日本国  

This paper reports a numerical investigation of the motion of spherical and non-spherical particles with/without gas blowing-out in a vertical uniform flow. The shape of non-spherical particle is adjusted basing on scanning of a coal particle using CT scanner. The aim of this work is to clarify the motion of non-spherical particle. As a first stage of the research, the Arbitrary Lagrangian-Eulerian (ALE) method is employed and validated by comparing with the experiment in which the motion of a sphere settling under gravity in water at rest is studied. Secondly simulations of particles with or without gas blowing-out in a vertical uniform flow are performed. Six kinds of particles - spherical or spheroidal particle with equivalent surface area, equivalent volume or equivalent sphericity to that of coal particle - are used. The result shows that the spheroidal particle with equivalent volume has a more similar accelerating motion to that of coal particle than spherical particle. For spheroidal particle, its distribution of Probability Density Function (PDF) of Drag coefficient (CD) value shows a possibility to make a CD equation with Re and particle’s Min-Max CD value. With gas blowing-out, the CD values of spherical and spheroidal particle decrease obviously because of the sharply decrease of CD value contributed by friction. It is also revealed that the motion of coal particle with irregular shape is significantly dependent on its shape, especially with gas blowing-out. New parameters can describe particle shape need to be developed.

開催年月日： 2015年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡国際会議場   国名：日本国  

開催年月日： 2015年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡国際会議場   国名：日本国  

開催年月日： 2015年5月 - 2015年6月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Sheraton Sand Key, Celarwater, Florida, USA   国名：アメリカ合衆国  

A reduced mechanism is derived from the detailed coal combustion kinetic mechanism proposed by Richter and Howard[1] for large scale calculations. The detailed mechanism includes fundamental reaction kinetics of light hydrocarbons and the kinetic mechanism of poly aromatic hydrocarbons (PAH). Therefore, we should consider the PAH reaction part when we try to regenerate a reduced mechanism. The detailed mechanism consists of 257 species and 1107 elemental reactions. In order to reduce the mechanism, firstly, a skeletal mechanism is developed from the detailed mechanism using a combination method of DRGEPSA and CSP method[2-4]. Many temporary mechanisms are tested in various combustion conditions of temperature, equivalent ratios, and pressures. About 30% of maximum error is allowed for a skeletal mechanism and most reasonable one is selected through a comparison of the error of each mechanism. Through this process, 64 species and 150 reactions are remained in the skeletal mechanism. And then, the reduced mechanism is generated from the skeletal version via quasi-steady state approximate (QSSA) method [5,6]. Now we are testing the temporary versions using the homogeneous reactor of CHEMKIN PRO. under various conditions of coal combustion, and we can get the reasonable result in a soon time. This mechanism will be installed in the LES of coal jet flame and we expect it can give detailed information at the chemical reaction part and reduce the computing time dramatically.

開催年月日： 2015年5月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：連合会館   国名：日本国  

開催年月日： 2015年4月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Palais des Papes, Avignon   国名：フランス共和国  

Characteristics of NOx formation in syngas combustion under O2/CO2 combustion condition is numerically investigated by means of homogeneous reactor model of CHEMKIN, a direct numerical simulation (DNS) with Arrhenius formulation (ARF) and DNS with the flamelet/progress variable approach (FPV) in comparison to air combustion condition. Results show that the major pathways for NO formation drastically change with O2/CO2 combustion condition in the zero-dimensional computation. The characteristics shown in the zero-dimensional computation is also confirmed in ARF. It is also revealed that the general feature of syngas combustion and the characteristics of NO formation can be precisely captured by FPV.

開催年月日： 2015年4月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Palais des Papes, Avignon   国名：日本国  

開催年月日： 2014年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：岡山理科大学加計学園50周年記念館   国名：日本国  

開催年月日： 2014年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：タワーホール船堀   国名：日本国  

開催年月日： 2014年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：タワーホール船堀   国名：日本国  

開催年月日： 2014年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：タワーホール船堀   国名：日本国  

開催年月日： 2014年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：岡山コンベンションセンター   国名：日本国  

In this study, the soot formation characteristics in a coal flame were investigated by using Time-Resolved Laser Induced Incandescence (TIRE-LII) and thermophoretic sampling (TS). The second harmonic wave (532 nm) from the Nd: YAG laser was employed as a light source for incandescence of soot particles. Two high speed CMOS camera with the image intensifier were used to detect the LII signal. The time interval between the first acquisition and the second acquisition of LII signals for the two cameras was set to 450 ns. From the obtained LII signal decay ratio and SEM images of the soot particle samples by TS, it was found that the size of primary soot particles was increased at the downstream region. The maximum soot volume fraction was observed at radial position of R = 4 - 5 mm. It was also found that the variation of the soot particle diameter distribution along the radial direction is not so large.

開催年月日： 2014年12月

記述言語：日本語  

開催地：岡山コンベンションセンター   国名：日本国  

開催年月日： 2014年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：岡山コンベンションセンター   国名：日本国  

開催年月日： 2014年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東北大学　川内北キャンパス　講義棟   国名：日本国  

開催年月日： 2014年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東北大学　川内北キャンパス　講義棟   国名：日本国  

This paper reports a numerical investigation of the motion of spherical and non-spherical particles in a vertical uniform flow. The aim of the work is to clarify the motion of non-spherical particle. As a first stage of the research, the Arbitrary Lagrangian-Eulerian (ALE) method is employed and validated by comparing with the experiment. Secondly simulations of spherical and non-spherical particles freely moving in a vertical uniform flow are performed. The result shows that the ellipsoid particle with equivalent volume has a higher accuracy than spherical particles. It is also revealed that the motion of coal particle with irregular shape is significantly dependent on its shape.

開催年月日： 2014年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪府立大学　中百舌鳥キャンパス   国名：日本国  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

筆者らは,「文部科学省HPCI戦略プログラム(分野4 次世代 ものづくり)」の下,複数の研究機関および重工メーカーからなる「次世代燃焼・ガス化装置設計システムの研究開発」に関する研究会を立ち上げて,燃焼・ガス化を扱う装置の設計や最適操作条件の選定を支援するための数値シミュレータの開発,およびその信頼性・有用性の検証に関する研究を進めている.本稿では,本プログラムにおいてこれまでに得られているいくつかの成果について紹介する.

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

Oxy-fuel IGCC system is expected to be a promising next-generation power generation system achieving high thermal efficiency and low carbon emission. In oxy-fuel IGCC condition, CO2 concentration in gasifier becomes higher than that in the conventional gasifier. CO2 generally behaves as a gasifying agent in gasification process, CO2 rich condition is expected to improve gasifier performance. However, the effect of rich CO2 concentration has not been clarified yet. This review describes results obtained by three-dimensional RANS based numerical simulation. In order to predict gasification reaction characteristics in a oxy-fuel IGCC gasifier, a new concept coal gasification model, which considers partially sharing active sites on a char surface by both CO2 and H2O, and a detailed chemical reaction model for the water-gas-shift reaction were implemented. Numerical simulation of both 3 t/d and 70 t/h coal gasifier were performed. Numerical results of 3 t/d coal gasifier were in good agreement with experimental data such as carbon conversion, product gas composition and gaseous temperature distribution, hence the developed method can qualitatively capture gasification process in a oxy-fuel IGCC gasifier. Furthermore, gasification characteristics in a 70 t/h coal gasifier were investigated. It was found that increasing O2 concentration up to 35% is needed to keep the same temperature level of the conventional air blown condition in the combustor region. It was also revealed that there is some possibility of improving a gasifier performance under the oxy-fuel IGCC condition by adequately controlling CO2 and O2 concentration.

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

微粉炭火炎中のすす生成機構を実験的に明らかにすることを目的として，基礎的な流れ場をもつ微粉炭燃焼場に対して，レーザ誘起赤熱法を適用した結果について，解説を行った．

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

独立行政法人科学技術振興機構(JST)研究開発戦略センター(CRDS)ならびに中国科学技術部(MOST)科学技術信息研究所(ISTIC)が共同で実施した，日中両国のトップレベル研究者を対象に行った，研究者を志した動機と研究テーマ，日本の研究環境，および，国際動向と日中科学技術協力に関する調査に協力した．

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

種別：大会・シンポジウム等 

参加者数：250

種別：学会・研究会等 

種別：学会・研究会等 

種別：査読等 

外国語雑誌　査読論文数：36

日本語雑誌　査読論文数：0

国際会議録　査読論文数：5

国内会議録　査読論文数：0

種別：大会・シンポジウム等 

参加者数：25,000

種別：大会・シンポジウム等 

参加者数：800

種別：大会・シンポジウム等 

参加者数：250

種別：大会・シンポジウム等 

参加者数：200

種別：学会・研究会等 

種別：学会・研究会等 

種別：査読等 

外国語雑誌　査読論文数：41

日本語雑誌　査読論文数：2

国際会議録　査読論文数：4

国内会議録　査読論文数：0

種別：大会・シンポジウム等 

参加者数：25,000

種別：大会・シンポジウム等 

参加者数：250

種別：大会・シンポジウム等 

参加者数：2,000

種別：学会・研究会等 

種別：査読等 

外国語雑誌　査読論文数：35

日本語雑誌　査読論文数：1

国際会議録　査読論文数：28

国内会議録　査読論文数：0

種別：大会・シンポジウム等 

参加者数：25,000

種別：大会・シンポジウム等 

参加者数：150

種別：大会・シンポジウム等 

参加者数：250

種別：大会・シンポジウム等 

参加者数：600

種別：大会・シンポジウム等 

参加者数：200

種別：大会・シンポジウム等 

参加者数：100

種別：大会・シンポジウム等 

参加者数：400

種別：学会・研究会等 

種別：学会・研究会等 

種別：査読等 

外国語雑誌　査読論文数：30

日本語雑誌　査読論文数：1

国際会議録　査読論文数：29

国内会議録　査読論文数：0

種別：大会・シンポジウム等 

参加者数：600

種別：大会・シンポジウム等 

参加者数：250

種別：査読等 

外国語雑誌　査読論文数：30

日本語雑誌　査読論文数：1

国際会議録　査読論文数：0

国内会議録　査読論文数：0

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

参加者数：300

種別：大会・シンポジウム等 

参加者数：250

種別：大会・シンポジウム等 

参加者数：50

種別：学会・研究会等 

種別：査読等 

外国語雑誌　査読論文数：47

日本語雑誌　査読論文数：3

国際会議録　査読論文数：26

国内会議録　査読論文数：0

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

参加者数：2,000

種別：大会・シンポジウム等 

参加者数：200

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

参加者数：50

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

参加者数：80

・　指導学生Wei Zhangが，原著論文（Zhang, W., Watanabe, H., Kitagawa, T., Numerical investigation of effects of particle shape on dispersion in an isotropic turbulent flow, Advanced Powder Technology, 29 (2018), 2048-2060.）を出版

指導学生Wei Zhangが，原著論文（Zhang, W., Tainaka, K., Ahn, s., Watanabe, H., Kitagawa, T., Experimental and numerical investigation of effects of particle shape and size distribution on particle's dispersion in a coaxial jet flow, Advanced Powder Technology, 29 (2018), 2322-2330）を出版

対象：社会人・一般,　学術団体,　企業,　市民団体,　行政機関

種別：講演会

対象：社会人・一般,　学術団体,　企業,　市民団体,　行政機関

種別：講演会

震災以降，議論百出のエネルギー問題について，火力エネルギーの観点から，今後の技術開発の方向性についての論点を提示した．低コスト化，二酸化炭素排出量の削減等，様々な切り口から，現在の技術開発動向を一般市民にも分かり易くレビューするとともに，市民間での意見交換を促した．