Language：Japanese   Publishing type：Doctoral thesis  

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DOI： 10.14988/0002000440

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

Port Fuel Injection (PFI) system in hybrid gasoline engines is frequently in cold condition due to use for electricity generation. Under cold condition, the fuel film forms on the intake port wall does not evaporate completely during the cycle, and the injected fuel spray impinges on it in the next cycle. In this paper, the process of fuel film formation under multi-cycle fuel injection condition is analysed by applying the Total Internal Reflection Laser Induced Fluorescence method. In addition, the particle size distribution of spray droplets was measured in quiescent conditions with Super High Spatial Resolution Photographymethod, which allows for whole spray imaging while maintaining the spatial resolution of small droplets. As a result, the fuel adhesion mass per injection increases as the critical Weber number increases with repeated fuel injections under quiescent conditions. Under cross flow conditions, fuel mass impinging on the wall is much smaller than under quiescent conditions. Accordingly, the fuel adhesion mass per injection is almost constant with repeated fuel injections because of the small increase in the critical Weber number.

DOI： 10.11351/jsaeronbun.55.113

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

<p>The atomization process of fuel spray injection in internal combustion engines affects the spray mixture formation process, the combustion characteristics, and the formation of toxic substances. Therefore, several optical measurement procedures have been developed and applied to capture spray features, including imaging methods and laser diagnostics. It has been concluded that the spatial resolution of fine spray droplets detection in imaging with silver halide film is much better than with a CCD imaging device. Therefore, the authors previously developed a novel imaging technique called Super High Spatial Resolution Photography (SHSRP), which allows for whole spray imaging while maintaining the spatial resolution of tiny droplets. This is a wide-field, high-resolution imaging method that can measure the entire spray area at the droplet scale. However, the image analysis method analyzes the intensity gradient of the outer edge of the droplet, and the accuracy of droplet analysis deteriorates as the droplet diameter is small. In this study, a new image analysis method with wide-field and high-resolution images acquired by SHSRP was developed to improve the analysis accuracy of spray droplets. The analysis method of depth of object field, which depends on droplet size, was changed from one-dimensional analysis of the intensity gradient of the outer edge of the droplet to two-dimensional analysis using the intensity deviation of the entire droplet area. For the developed analysis method, analysis of error based on scattering theory was conducted and the droplet capture ratio in diesel spray was analyzed to verify the accuracy. As a result, it was found that the particle size distribution obtained has no peaks due to noise effects, and that the presented analysis method is accurate enough to characterize the particle size distribution of diesel spray.</p>

DOI： 10.1299/transjsme.23-00141

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Publisher：SAE Technical Papers  

Computational Fluid Dynamics (CFD) simulation is widely used in the development and validation of automotive engine performance. In engine simulation, spray breakup submodels are important because spray atomization has a significant influence on mixture formation and the combustion process. However, no breakup models have been developed for the fuel spray with plate-type multi-hole nozzle installed in port fuel injection spark ignition (SI) engines. Therefore, the purpose of this study is to simulate spray formation in port fuel injection precisely. The authors proposed the heterogeneous sheet breakup model for gasoline spray injected from plate type multi-hole nozzle. The novel breakup model was developed by clarifying the phenomenological mechanism of the spray atomization process. In this paper, this model was improved in dispersion characteristics and evaluated by the comparison of the model calculation results with experimental data. As the results, the heterogeneous sheet breakup model can describe accurately spray atomization feature of the spray injected from the plate type multi- hole nozzle in port fuel injection condition.

DOI： 10.4271/2023-32-0091

Scopus

Publisher：SAE Technical Papers  

In this study, the authors analyze the concentration distribution of an evaporative spray mixture with LIEF (Laser induced exciplex fluorescence) method, which is a type of optical measurement. LIEF method is one of the optical measurements for obtaining the spray concentration distribution for separating vapor/liquid phases based on the fluorescence characteristics. In this paper, a quantitative concentration distribution analysis method for wall impingement spray in heterogeneous temperature field has been proposed. Then, a series of experiments were performed in varying injection pressure and ambient density. As a result, a two-dimensional concentration distribution was obtained for the free spray and wall impingement spray.

DOI： 10.4271/2023-32-0015

Scopus

Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

In direct injection spark ignition (DISI) engines, strict control of pollutant emissions at cold start is required to comply with new emission regulations. To clarify the effect of the impingement distance between the nozzle and the wall on the film formation process under low temperature conditions and the relationship between heat transfer and evaporation characteristics of the fuel film in an actual engine, total internal reflection laser induced fluorescence (TIR-LIF) method was applied to visualize the fuel film formation process. The parameters are 14mm, 28mm, 42mm, and 57 mm in wall impingement distance and the wall surface temperatures are 253 K and 293 K. As a result, the wall impingement distance increases, the momentum of the spray droplets just before impingement on the wall is smaller and it follows the gas flow in the spray more easily, resulting in a decrease in the amount of fuel adhesion on the wall. At a wall impingement distance of 14 mm, the amount of dispersion from the fuel film increases due to the large momentum of the spray droplets. In DISI engines, the fuel film easily residual in the intake process due to the reduction of heat transfer from gas to liquid and increase in heat require for evaporation of the fuel film at the earlier injection timing.

DOI： 10.11351/jsaeronbun.54.711

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

In direct injection spark ignition engines, PM reduction under cold conditions is important, and controlling liquid film adhesion by spray wall interaction is a key issue. In this study, to control the amount of liquid film adhesion by wall impinging spray, fuel film analysis method was developed applying the total internal reflection laser induced fluorescence (TIR-LIF) method, which can estimate the film thickness and the film temperature those change unsteadily during the film formation process. Decrease in fuel temperature and wall temperature increases the We number of spray droplets, which increases the amount of splash by droplet impingement and decreases the amount of film adhesion. However, the effects of fuel spray and fuel film temperature on the film formation process of impinging wall spray under low temperature conditions is not clear. In this paper, the spray droplets impinging on the wall were set in the same condition by changing the wall temperature only. The effect of the temperature change on the film formation process was estimated by measuring the film temperature and thickness of the spray droplets while their impingement on the wall. It is found that as the liquid film temperature decreased, the amount of droplet adhesion to the liquid film decreases because the amount of splash increases when droplets imping on the film.

DOI： 10.11351/jsaeronbun.54.704

CiNii Research

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Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

<p>Direct fuel injection spray is used to improve thermal efficiency and environmental performance in SI engines. A mixture is formed through momentum exchange between fuel droplets and ambient gas, along with mixing accompanied by droplets evaporation and diffusion. Both the droplets development derived from the liquid fuel atomization and the entrainment ambient air predominate the mixture formation process. The purpose of this study is to elucidate the momentum exchange characteristics of the spray formed by a single-hole injector for direct injection gasoline engines. To clarify the momentum exchange characteristics of spray droplets, the spray was visualized by optical experiments and the spray development process was analyzed. The parameters are injection pressure and ambient density. A comparison of experimental results and a model analysis of a single droplet movement was conducted, and different of deceleration characteristics were evaluated. In the case of the fuel spray, the induced ambient air by the spray tip droplets decreases the relative velocity between the spray droplets and the spray internal flow. A model for predicting the temporal variation of the spray tip penetration from the different of momentum exchange characteristics between the spray and the droplet was proposed.</p>

DOI： 10.1299/transjsme.23-00037

CiNii Research

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

CFD (Computational Fluid Dynamics) simulations are widely used for the research and development in the field of thermal fluidics, including internal combustion engines􀀑 Spray breakup models significantly affect the liquid film formation on the intake port wall impingement and mixture formation. However, there is no model for the atomization process under port fuel injection conditions with the plate-type multi-hole nozzles which have great atomization characteristics. The purpose of this study is to investigate the spray atomization process and predict the breakup process in multi-hole nozzle spray for port fuel injection. In previous studies, the authors have experimentally investigated the liquid sheet breakup process and droplet behavior of fuel sprays under port fuel injection conditions, and have modeled the droplet generation process based on the liquid sheet breakup theory. In this report, liquid sheet breakup model was modified and simulated the spray atomization process.

DOI： 10.11351/jsaeronbun.54.8

CiNii Research

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Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

In a spark-ignition engine with intake port fuel injection, fuel is sprayed into the intake port under flow conditions and atomized droplets flow into the cylinder, some of which adhere to the intake port wall and form a liquid film. The liquid film adhered to the intake port is a factor in combustion fluctuations due to cycle-to-cycle variations of the air-fuel mixture in the cylinder, as well as unburned hydrocarbons and soot emissions. In this study, a wind tunnel experimental apparatus simulated an intake port was constructed to understand the wall adhesion characteristics of fuel spray in the intake port during engine startup and cold startup conditions. Scattered light photography was used to observe fuel spray characteristics in static and flow conditions, and total internal reflection laser-induced fluorescence (TIR-LIF) was applied to analyze the wall adhesion characteristics of fuel sprays. As a result, in the static field, the spray interaction increased with increasing injection pressure, and the amount of wall adhesion increased. However, in a flow field, the spray follows the flow as the injection pressure increases, and the amount of adhesion decreases.

DOI： 10.11351/jsaeronbun.54.14

CiNii Research

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

In a direct injection spark ignition engine, strict control of pollutant emissions at cold start is required to comply with new regulations. Fuel temperature and wall temperature are especially important parameters because they are closely related to the fuel film formed by spray impingement on the wall. The purpose of this study is to clarify the mixture and fuel film formation process with wall impingement spray under low temperature fuel and wall conditions. Construction of a spray experiment equipment that can simultaneously cool fuel temperature and wall temperature, and Total internal reflection laser induced fluorescence (TIR-LIF) method was applied to the fuel film formed by wall impingement spray. TIR-LIF method can measure fuel film thickness by fluorescence from fuel film during the spray injection without the influence of the spray droplet. In this paper, the fuel and wall temperatures were controlled from 293 K to 253 K to investigated film formation process during spray injection. In addition heat of evaporation considering heat capacity of fuel film was estimated.

DOI： 10.11351/jsaeronbun.53.1192

CiNii Research

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan, Inc.  

ABSTRACT: A breakup model used in spray combustion simulations was developed to predict the breakup process of spray droplets, which has large influences on the mixture formation and the combustion process in internal combustion engines. Taylor Analogy Breakup (TAB) Model is widely used as a droplet breakup model. Improved TAB (ITAB) Model has been developed by improving model constants and the breakup/non-breakup boundary condition of TAB Model. ITAB Model reproduces the dimensionless breakup time based on the observation results of the single droplet breakup behavior and CFD simulation results. In this study, calculation methods of droplet diameter and droplet velocity after breakup in ITAB Model are modified to avoid fitting model constants during spray analysis. Droplet diameter after breakup is determined by calculating Sauter Mean Diameter and using the droplet diameter distribution after breakup based on the observation results of the single droplet breakup behavior. The calculation constant for Sauter Mean Diameter is a function of Weber number to reproduce the breakup phenomenon of single droplets. Droplet velocity after breakup is calculated based on the energy conservation law of droplets used in Enhanced TAB Model. This model shows that Sauter Mean Diameter after breakup is almost same and perpendicular motion of droplets after breakup is more active than TAB Model. This model also considers the effects of the fuel physical properties on breakup characteristics. Model analysis shows that droplet diameter after breakup of the high boiling point component fuel is larger under same conditions and the effect of temperature change is larger than that of the low boiling point component fuel.

DOI： 10.20485/jsaeijae.13.4_155

Scopus

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Other Link： https://www.jstage.jst.go.jp/article/jsaeijae/13/4/13_20224546/_article/-char/ja

Publisher：COMODIA 2022 - 10th International Conference on Modeling and Diagnostics for Advanced Engine Systems  

In spray combustion simulation, many breakup models have been developed and introduced into CFD simulation to predict the breakup process of spray droplets, which is very important for the mixture formation process. Theoretical models such as Taylor Analogy Breakup (TAB) Model are widely used as a droplet breakup model. To make TAB Model an experimental model, Improved TAB (ITAB) Model has been developed based on the observation results of the single droplet breakup process. In this study, Modified Improved TAB (MITAB) Model was developed as the new droplet breakup model. The model modifies calculation methods of droplet diameter and droplet velocity after breakup in ITAB Model based on observation results of the single droplet breakup process. WAVE-MITAB Model which combined with WAVE Model and MITAB Model was introduced into KIVA as the new spray breakup model, and CFD analysis was performed. In addition, the applicability of WAVE-MITAB Model to non-evaporating diesel spray was investigated by varying the calculation constant of WAVE Model and comparing with other spray breakup models.

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)  

J-GLOBAL

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

<p>In a direct-injection gasoline engine, strict control of pollutant emissions at cold start is a critical point to comply with new regulations, and the fuel film formed by spray impingement on the piston wall is closely related. In this context, the purpose of this study is to clarify the fuel film formation process of spray impinging on a low temperature wall. Total internal reflection laser induced fluorescence (TIR-LIF) method was applied to the fuel film formed by wall impingement gasoline spray. TIR-LIF method can measure the fluorescence from fuel film without the influence of the spray droplet. The fluorescence intensity from the fuel film depends on the film thickness and temperature. In this paper, the temperature dependence of the fluorescence from the fuel film was investigated under the condition that the laser light is totally reflected from the top surface of the film. The order of magnitude of the heat transfers due to the mixing of spray droplets and fuel film, the heat transfer from the ambient gas, and the heat transfer from the wall were compared and modeled. A method to simultaneously calculate the unsteady change in fuel film thickness and fuel film temperature was developed. Then, the model analysis method was applied to the measured experimental data and verified.</p>

DOI： 10.1299/transjsme.21-00379

CiNii Research

J-GLOBAL

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

The purpose of this study is to investigate the effect of spray-spray interaction on the entrainment mechanism in diesel combustion field. In this paper, the ambient air flow is measured with laser induced fluorescence and particle image velocimetry (LIF-PIV), and the backflow arrival distance is used to understand the ambient air flow. The interaction region between sprays is estimated from the geometric relationship of the sprays in the multi hole nozzle case, and the indicator of influence by the spray-spray interaction on the entrainment mechanism is proposed. The correlation between the experimentally measured backflow arrival distance and the theoretically calculated degree of the influence by spray-spray interaction on the entrainment mechanism was investigated, and the effectiveness was evaluated.

DOI： 10.11351/jsaeronbun.53.484

CiNii Research

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Automotive Engineers of Japan  

In this study, the spray behavior of direct injection gasoline engines is analyzed under low temperature conditions. DISI engines have a problem of the emission characteristics during cold start. Fuel injection is closely related to PM/PN. The purpose of this study is to understand the spray behavior under low temperature conditions. The experimental equipment to control the fuel temperature and the wall temperature was constructed assuming low temperature condition up to -20°C (253K). The characteristics of free spray and wall impingement spray were measured and analyzed. As the fuel temperature decreased, the spray tip penetration increased by 4.7 % at a fuel temperature of 273 K and by 8.4 % at fuel temperature of 253 K compared to 293 K. The spray angle decreased by 6.4 % at 273 K compared to 293 K, and by 14 % at 253 K. In the case of the wall impingement spray, maximum impingement spray spread distance was suppressed by the change in wall temperature, but the effect of the ambient temperature was also considered.

DOI： 10.11351/jsaeronbun.53.491

CiNii Research

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

The fuel injection in diesel engines have a significant effect on the engine performance. But there is little knowledge on the characteristics of dispersion of liquid phase concentration. The purpose of this study is to clarify the dispersion process of the liquid phase of diesel spray through quantitative analysis of the liquid phase concentration distribution in non-evaporating diesel spray. In this paper, a quantitative analysis method of the liquid phase concentration of diesel spray under non-evaporative conditions is developed. The cross-sectional mass flow of the fuel was obtained using the momentum theory from the measured concentration distribution of the liquid phase with the laser induced fluorescence method. The relationship between the fluorescence intensity and the liquid phase concentration was estimated. In addition, a scheme was developed to account for the attenuation of the laser light and fluorescence, which results in a quantitative spatial distribution of the liquid phase concentration. Using this method, the dispersion process of the liquid phase in diesel spray was evaluated.

DOI： 10.1299/transjsme.21-00376

CiNii Research

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>In compression ignition engines, the physical and chemical properties of the fuel are important factors that governed the formation of the air fuel mixture and the subsequent combustion process¹). Our study has proposed a concept of fuel design in which a fuel with a high boiling point is mixed with a fuel with a low boiling point as a spray control method for low emission and combustion control in engine systems. A multicomponent fuel model was proposed to estimate the vapor-liquid equilibrium and physical properties of the mixed fuel, and a two-component fuel spray feature was analyzed using the KIVA code. However, in the previous studies, the maximum fuel injection pressure was set on 15 MPa, and the analysis for high injection pressures in recent diesel sprays has not been performed. In this study, a multicomponent fuel model was used to analyze a two-component fuel spray under high injection pressures, and a large difference was observed between the experimental results of liquid core length and the calculation results. In the analysis, the MTAB model, which models the breakup phenomenon of fuel droplets in low Weber number region, was used as the breakup model, and it is considered necessary to use a breakup model that analyze the breakup behavior in high Weber number region as the fuel injection pressure increases. In this study, the behavior of multicomponent fuel sprays was analyzed by using the WAVE-MTAB model, which models the breakup phenomenon of diesel sprays under high fuel injection pressure conditions²). The spray tip penetration and the spatial distribution characteristics of each component fuel were verified. As a result, as Figure 1 shows that the higher boiling point fuel in a two-component fuel spray injected at high pressure is mainly distributed in the tip of the spray than the lower boiling point fuels.</p>

DOI： 10.1299/jsmekansai.2021.96.2203

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>This paper reports the quantitative analysis of vapor concentration in the two-phase mixture region of liquid and vapor with Laser Induced Exciplex Fluorescence（LIEF）for the unsteady evaporating gasoline type spray. The exciplex fluorescence method, developed by Melton, is a method to optically separate the fluorescence from the liquid and vapor phases, but quantitative analysis of vapor concentration in the two-phase mixture region of liquid and vapor is difficult due to fluorescence cross talk. In this study, iso-octane（92 vol%）, benzene（4 vol%）, and triethylamine（4 vol%）were used as fluorescent agents that emit excited complex fluorescence. This fluorescence can optically separate from the liquid phase and the vapor phase, respectively. I tested the dependence of the fluorescence characteristics on the vapor concentration, ambient pressure, and ambient temperature to quantify the vapor spatial concentration. The relationship between the vapor concentration and the fluorescence intensity ratio was equivalent to the theoretical relationship. Furthermore, the relationship among the fluorescence intensity ratio and ambient conditions could be considered by the formulation1). For quantitative measurement, I used the image analysis method of vapor spatial concentration quantification measurement in direct injection diesel spray developed by Senda et al. The method was used to quantify the vapor spatial concentrations in the two-phase mixture region of liquid and vapor by image processing that considered the fluorescence cross talk between the liquid and vapor phases2). The resulting spatial concentration distribution of the liquid phase in the two-phase mixture region of liquid and vapor in the spray cross section is shown in Figure 1.</p>

DOI： 10.1299/jsmekansai.2021.96.31005

CiNii Research

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

The multicomponent fuel model, which estimates vapor-liquid equilibrium and physical properties of fuel mixtures, can represent heterogeneous fuel concentration distribution due to differences in evaporation characteristics of two-component fuel spray. In this paper, the concentration distribution characteristics of each component of a two-component fuel spray were measured by laser-induced fluorescence method and numerically calculated using the multicomponent fuel model with fuel injection pressure and ambient density as parameters.

DOI： 10.11351/jsaeronbun.52.923

CiNii Research

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

A multicomponent fuel model, which estimates the gas-liquid equilibrium and property values of the fuel mixture, can represent the fuel concentration distribution characteristics of each component of a multicomponent fuel spray. In this paper, the WAVE-MTAB model is applied to a breakup model in order to simulate the spray characteristics of a twocomponent fuel spray under high pressure injection pressure conditions. As a result, the two-component spraying behavior and the fuel concentration distribution of each component in a multicomponent fuel spray under high pressure injection conditions could be reproduced in comparison with the experimental results.

DOI： 10.11351/jsaeronbun.52.125

CiNii Research

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

Jet configuration of a multi-hole nozzle spray for gasoline port injection is a liquid sheet. In this paper, novel modeling scheme of the generated droplets is reported. The spray atomization process is modeled using linear stability theory in liquid jet, including the injection feature of the liquid sheet, the breakup process of the liquid sheet, and the breakup process from ligaments to droplets. In addition, a model is proposed to provide the droplet size distribution using the statistical theory of uniform turbulence. As a result, it is found that the droplet generation length coincides quantitatively in the region where the wave growth rate is higher. However, due to the nonlinear effects of waves, the prediction accuracy of large droplet generation is reduced. Therefore, the experimental results of droplet generation length were used to correct the breakup time. The droplet size distribution modeled using the corrected breakup time can represent the atomization effect with changing fuel injection pressure.

DOI： 10.11351/jsaeronbun.52.1047

CiNii Research

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

In this paper, the dynamic characteristics of fuel spray droplet of multi-hole nozzle for port fuel injection were investigated by applying Particle Tracking Velocimetry (PTV) method. The nozzle angle, injection differential pressure, and atmosphere density were selected as experimental parameters, and the Weber number and dispersion angle of the fuel droplets were measured. The results show that the dispersion angles of the fuel droplets are different depending on the droplet size. Also, the direction of droplet dispersion is greatly influenced by injection conditions, and less influenced by the gas-liquid interaction after injection.

DOI： 10.11351/jsaeronbun.52.677

CiNii Research

Language：Japanese   Publisher：Society of Automotive Engineers of Japan  

This paper reports the atomization process of fuel spray in gasoline intake port injection. The classification of the jet configuration using dimensionless numbers in fluid dynamics was estimated that the fuel spray in the port fuel injection condition is in the wavy region. A shadow graph photography was used to visualize the liquid sheet breakup process. It was confirmed that the fuel injected from the nozzle formed a liquid sheet. For the subsequent breakup, it was found that the liquid sheet broke up into droplets with a distribution along the axial distance of the nozzle, and the secondary breakup, in which the droplets broke up into smaller droplets, rarely occurred.

DOI： 10.11351/jsaeronbun.52.671

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>This paper reports the quantitative method of vapor concentration in unsteady evaporating gasoline type spray with Laser Induced Exciplex Fluorescence（LIEF）. The LIEF is an exciplex fluorescence method developed by Melton to visualize the liquid and vapor phases separately. In this study, iso-octane（92 vol%）, benzene（4 vol%）, and triethylamine（4 vol%） were used as a fluorescent agent that emit excited complex fluorescence that can optically separate fluorescence from the liquid phase and the vapor phase respectively. We tested the dependence of the fluorescence characteristics on the vapor concentration, ambient pressure, and ambient temperature when quantifying the vapor concentration. The relationship between the vapor concentration and the fluorescence intensity ratio was similar to the theoretical relationship. Furthermore, the relationship between the fluorescence intensity ratio and each parameter could be considered as a function of only its parameter. Since the fluorescence intensity is proportional to the laser incident light intensity and the emitted laser light has a Gaussian intensity distribution, the intensity distribution of the laser sheet light could be predicted, and the captured image could be corrected. For quantitative measurement, we used the image analysis method of vapor concentration quantification measurement of direct injection diesel spray developed by Senda et al. The quantitative distribution of vapor concentration was measured by applying the method to the results of simultaneous measurement of Mie scattering, exciplex fluorescence, and monomer fluorescence.</p>

DOI： 10.1299/transjsme.20-00099

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>This paper reports the quantitative analysis of vapor concentration in the mixture-liquid two-phase region with Laser Induced Exciplex Fluorescence（LIEF）for the unsteady evaporating gasoline type spray. These methods were used to analyze the mixture-liquid two-phase characteristics in the process of mixture formation. The exciplex fluorescence method, developed by Melton, is a method to optically separate the fluorescence of the liquid and vapor phases, but quantitative analysis of vapor concentration in the mixture-liquid two-phase e region is difficult due to fluorescence cross talk. In this study, the quantitative analysis of vapor concentrations using the average temperature of mixing was used to quantify the vapor concentrations in the mixture-liquid two-phase region by image processing that considers the fluorescence cross talk between the liquid and vapor phases. As a result, the vapor concentration, the temperature of the mixture, and the concentration distribution of the liquid phase in the mixture-liquid two-phase region of the spray cross section were obtained. Based on these results, the correlation diagram between vapor concentration and fluorescence intensity of the liquid phase and the relative frequency distribution of vapor concentration were calculated. A comparison was made between the characteristic values of the fuel and the temperature under the experimental conditions. It was found that the spray consisted mainly of a region where the liquid phase was almost absent and dilute vapors were formed, and a region where the liquid phase was present and formed dense vapors. The same analysis was performed to evaluate the process of vaporization of the spray mixture at different times from the start of injection.</p>

DOI： 10.1299/transjsme.20-00294

CiNii Research

Event date： 2023

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非定常気液二相流場における噴霧微粒化および混合気形成過程のモデル構築と数値解析
23KJ2075

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NACE「ディーゼルエンジンの正味熱効率改善」研究会

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https://www.doshisha.ac.jp/se/news/detail/055-qj4zRq.html

https://research.doshisha.ac.jp/news/news-detail-59/

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