| 1. |
Chiyoko Hirose, Daiki Nakashima, Chiharu Aoyama, Hiroaki Watanabe, An Image Analysis for Understanding the Ascending Behavior of Methane Bubbles in the Ocean, AGU Fall Meeting 2022, 2022.12. |
| 2. |
坂本祥太郎, Panlong Yu, 内田正宏, 渡邊裕章, 北川敏明, 航空用ジェットエンジン燃焼器を対象としたLESにおける燃焼モデルの精度検証, 日本ガスタービン学会 第50回定期講演会, 2022.10. |
| 3. |
Hiroaki Watanabe, Combustion Simulation: For Carbon Neutrality in 2050, 64th KOSCO Symposium, 2022.11. |
| 4. |
Koshi Kawamoto, Masato Mikami, Hiroaki Watanabe, Numerical simulation of ignition and flame spread of droplet-cloud elements, 日本マイクログラビティ応用学会 第34回学術講演会, 2022.09. |
| 5. |
Panlong Yu, Hiroaki Watanabe, Large-eddy Simulation of Non-premixed Flames in an Inhomogeneous Diluted Jet Hot Coflow, 日本燃焼学会 第60回燃焼シンポジウム, 2022.11. |
| 6. |
Panlong Yu, Hiroaki Watanabe, Investigation of Ammonia/Hydrogen Laminar Flames by 2D Direct Numerical Simulation, 日本機械学会 第100期流体工学部門講演会, 2022.11. |
| 7. |
Sujeet Yadav, Panlong Yu, Hiroaki Watanabe, Numerical Investigation of Co-Combustion Characteristics of Coal-NH3 Flame Using Three Mixture Fraction-FPV-LES, 日本燃焼学会 第60回燃焼シンポジウム, 2022.11. |
| 8. |
Sujeet Yadav, Panlong Yu, Hiroaki Watanabe, INFLUENCE OF THE THIRD STREAM TO A THREE-FEED NON-PREMIXED COMBUSTION SYSTEM, The 13th Pacific Symposium on Flow Visualization and Image Processing, 2022.09. |
| 9. |
吉村忍, 山田知典, 渡邊裕章, 黒瀬良一, 吉田隼也, 淀薫, 複数の並列ソルバーを連携活用した石炭ガス化炉スーパーシミュレーション, 第34回計算力学講演会, 2021.09. |
| 10. |
Chiyoko Hirose, Daiki Nakashima, Chiharu Aoyama, Hiroaki Watanabe, The statistical analysis of seeping behavior of methane bubbles from seafloor, AGU Fall Meeting 2021, 2021.12. |
| 11. |
池田孝, 渡邊裕章, 黒瀬良一, 北川敏明, イソオクタン伝播過濃不安定火炎のすす生成に及ぼす当量比の影響, 第59回燃焼シンポジウム, 2021.11. |
| 12. |
渡邊裕章, 三上真人, 野村浩司, 菅沼祐介, 瀬尾健彦, 菊池政雄, Group Combustion-2におけるモデリングと数値解析, Conference on the Japan Society of Microgravity Application, 2021.10. |
| 13. |
Hiroaki Watanabe, Panlong Yu, Flamelet modeling and numerical simulation on complex combustion systems, Third International Conference of Chemical, Energy and Environmental Engineering, 2021.07. |
| 14. |
Panlong Yu, Hiroaki Watanabe, Large-eddy simulation of a hot coke oven gas flow reforming with consideration of heat loss, 日本機械学会第98期流体工学部門講演会, 2021.11. |
| 15. |
Panlong Yu, Ryoichi Kurose, Hiroaki Watanabe, Investigation of a flamelet model for staged combustion, 第49回日本ガスタービン学会定期講演会, 2021.10. |
| 16. |
渡邊裕章, 戸田信一, 傳田知広, 棧敷和弥, 白石裕司, 梅野裕太, ストーカ式焼却炉における都市ごみの燃焼数値シミュレーション, 日本燃焼学会第58回燃焼シンポジウム, 2020.12. |
| 17. |
Yu, P., Pitsch, H., Nishiie, T., Kitagawa, T., Watanabe, H., Large-eddy simulation of a three-feed non-premixed flame for an oxy-fuel gas turbine burner, 日本ガスタービン学会第48回定期講演会, 2020.10. |
| 18. |
Panlong Yu, Hiroaki Watanabe, Isao Yuri, Hiroyuki Nishida, Toshiaki Kitagawa, Modeling and simulation of quasi-two-dimensional flamelet model for a three-feed non-premixed combustion system, The 17th International Conference on Numerical Combustion, 2019.05. |
| 19. |
Seongyool Ahn, Hiroaki Watanabe, Toshiaki Kitagawa, Numerical assessment on blended pulverized coal combustion by large eddy simulation, The 59th KOSCO Symposium, 2019.11. |
| 20. |
Masaya Muto, Hiroaki Watanabe, Ryoichi Kurose, Large eddy simulation of pulverized coal combustion in multi-burner system: Effect of in-furnace blending method on unburnt carbon distribution, ASME-JSME-KSME Joint Fluid Conference 2019, 2019.07. |
| 21. |
Seongyool Ahn, Kouki Maeda, Hiroaki Watanabe, Toshiaki Kitagawa, Numerical investigation of NOx formation with a derived global reaction mechanism on a turbulent pulverized coal combustion furnace, ASME-JSME-KSME Joint Fluid Conference 2019, 2019.07. |
| 22. |
Hiroaki Watanabe, Ryoichi Kurose, Kenji Tanno, LES modeling and simulation of coal gasification on an O2-CO2 gasifier in the oxy-fuel IGCC system, ASME-JSME-KSME Joint Fluid Conference 2019, 2019.07. |
| 23. |
Shigeo Saitoh, Hiroaki Watanabe, Chiharu Aoyama, Transportation method of methane hydrate collected in the recovery area of Sea of Japan based on energy profit ratio (EPR), AGU Fall Meeting 2019, 2019.12. |
| 24. |
Tatsuo Yoshino, Chiharu Aoyama, Hiroaki Watanabe, Yasushi Kawagishi, Research relating to use membrane structure in collecting methane hydrate: Conical shape membrane structure for collecting purpose, AGU Fall Meeting 2019, 2019.12. |
| 25. |
Yasushi Kawagishi, Chiharu Aoyama, Hiroaki Watanabe, Tatsuo Yoshino, Membrane structure for methane hydrate recovery: Adhesion of membrane film and methane hydrate, AGU Fall Meeting 2019, 2019.12. |
| 26. |
Hazim Shehab, Hiroaki Watanabe, Ryoichi Kurose, Toshiaki Kitagawa, Numerical study on the influence of turbulence scale on spherical hydrogen flame development, The Second Pacific Rim Thermal Engineering Conference (PRTEC2019), 2019.12. |
| 27. |
Panlong Yu, Hiroaki Watanabe, Ryoichi Kurose, Toshiaki Kitagawa, Investigation on flamelet characteristics of a three-feed non-premixed combustion system, The Second Pacific Rim Thermal Engineering Conference (PRTEC2019), 2019.12. |
| 28. |
Hiroaki Watanabe, Modeling and simulation of pulverized coal combustion, The 2nd International symposium on Advanced Measurement, Analysis and Control of Energy and Environment (AMACEE2019), 2019.12. |
| 29. |
Panlong Yu, Hiroaki Watanabe, Heinz Pitsch, Isao Yuri, Hiroyuki Nishida, Toshiaki Kitagawa, Large-eddy simulation of quasi-two-dimensional flamelet model for a three-feed non-premixed combustion system, The 2nd International symposium on Advanced Measurement, Analysis and Control of Energy and Environment (AMACEE2019), 2019.12. |
| 30. |
Hazim Shehab, Hiroaki Watanabe, Ryoichi Kurose, Toshiaki Kitagawa, Numerical study on the influence of turbulence scale on spherical hydrogen flame development, 第57回燃焼シンポジウム, 2019.11. |
| 31. |
Hiroaki Watanabe, Ryoichi Kurose, Shinobu Yoshimura, Tomonori Yamada, Large-scale Multiphysics Simulation of a Multiphase Reacting Flow, The 16th International Conference on Flow Dynamics (ICFD2019), 2019.11. |
| 32. |
渡邊裕章, 梶谷史朗, 黒瀬良一, 石炭ガス化炉内のガス化反応・スラグ流シミュレーション, 第56回石炭科学会議, 2019.10. |
| 33. |
渡邊裕章, 内田正宏, 廣光永兆, 堀高太郎, 航空用エンジン燃焼器の全周ラージ・エディ・シミュレーション, 第47回日本ガスタービン学会定期講演会, 2019.09. |
| 34. |
Seongyool Ahn, Hiroaki Watanabe, Toshiaki Kitagawa, Numerical study on the effect of coal composition on a pilot-scale turbulent coal combustion furnace, The 12th Asia-Pacific Conference on Combustion (ASPACC2019), 2019.07. |
| 35. |
Seongyool Ahn, Kenji Tanno, Hiroaki Watanabe, Numerical investigation of gasification characteristics on an oxy-fuel gasifier, International Conference on Polygeneration (ICP2019), 2019.05. |
| 36. |
Panlong Yu, Hiroaki Watanabe, Ryoichi Kurose, Toshiaki Kitagawa, Study on quasi-two-dimensional flamelet model for a three-feed non-premixed combustion system, International Conference on Polygeneration (ICP2019), 2019.05. |
| 37. |
Hiroaki Watanabe, Chiharu Aoyama, Daiki Aoyama, Yasushi Kawaguchi, Conceptual design and life cycle assessment of a new utilization technology of seafloor methane gas venting, EGU General Assembly 2019, 2019.04. |
| 38. |
H. Takahashi, Nozomu Hashimoto, Hiroaki Watanabe, Ryoichi Kurose, Osamu Fujita, Soot formation prediction in a pulverized coal combustion field by large eddy simulation with TDP model, The 37th International Symposium on Combustion, 2018.08. |
| 39. |
Jun Hayashi, Nozomu Hashimoto, Noriaki Nakatsuka, Kazuki Tainaka, Kenji Tanno, Hiroaki Watanabe, Hisao Makino, Simultaneous imaging of Mie scattering PAHs laser induced fluorescence and soot laser induced incandescence to a lab-scale turbulent jet pulverized coal flame, The 37th International Symposium on Combustion, 2018.08. |
| 40. |
Seongyool Ahn, Panlong Yu, Hiroaki Watanabe, Ryoichi Kurose, Toshiaki Kitagawa, Flamelet LES for two-phase combustion in a pilot scale turbulent pulverized coal combustion furnace, 第32回数値流体力学シンポジウム, 2018.12. |
| 41. |
Seongyool Ahn, Hiroaki Watanabe, Toshiaki Kitagawa, Large-eddy simulation of a coal jet flame with a skeletal mechanism, 第46回可視化情報シンポジウム, 2018.09. |
| 42. |
Seongyool Ahn, Gyungmin Choi, Hiroaki Watanabe, Numerical analysis on an effect of turbulent intensity for a dual swirl pulverized coal combustion flame, The 55th KOSCO Symposium, 2017.11. |
| 43. |
Panlong Yu, Hiroaki Watanabe, Ryoichi Kurose, Toshiaki Kitagawa, Study on quasi-two-dimensional flamelet model in a three-feed non-premixed combustion system, 第56回日本燃焼シンポジウム, 2018.11. |
| 44. |
Chiharu Aoyama, Hiroshi Fukuoka, Hiroaki Watanabe, A novel method to explore submarine gas resources from plumes originating from seafloor surface and/or shallow subsurface methane hydrates, 9th International Conference on Gas Hydrate, 2017.06. |
| 45. |
Hazim Shehab, Ryoichi Kurose, Hiroaki Watanabe, Toshiaki Kitagawa, Numerical study on the effects of turbulence scale on spherically propagating hydrogen flames, 自動車技術会2018年春季大会, 2018.05. |
| 46. |
Hazim Shehab, Hiroaki Watanabe, Masaya Muto, Ryoichi Kurose, Toshiaki Kitagawa, Numerical study on the effects of turbulence intensity and scale on spherically propagating flames, 第28回内燃機関シンポジウム, 2017.12. |
| 47. |
高橋弥楊, 橋本望, 渡邊裕章, 黒瀬良一, 藤田修, TDPモデルを用いたLarge Eddy Simulationによる0.5kg-coal/h微粉炭ジェットバーナ燃焼場のすす生成予測, 第55回燃焼シンポジウム, 2017.11. |
| 48. |
Panlong Yu, 則永行庸, 渡邊裕章, 北川敏明, HCOGベンチスケール改質器内流れのLarge-eddy simulation, 第55回燃焼シンポジウム, 2017.11. |
| 49. |
青山千春, 谷和夫, 福岡浩, 渡邊裕章, 川岸靖, 表層型メタンハイドレート回収技術に係わる調査研究 ドーム状の膜構造物による回収技術の検討, 第9回メタンハイドレート総合シンポジウム（CSMH-9）, 2017.10. |
| 50. |
丹野賢二, 渡邊裕章, 牧野尚夫, 火力発電所における炭種適合性評価ツールの開発, 粉体工学会2017年度秋期研究発表会, 2017.10. |
| 51. |
泰中一樹, 橋本望, 梅本賢, 中塚記章, 林潤, 渡邊裕章, 赤松史光, 牧野尚夫, 微粉炭燃焼場でのすす生成特性解明に向けた計測技術, 粉体工学会2017年度秋期研究発表会, 2017.10. |
| 52. |
武藤昌也, 渡邊裕章, 黒瀬良一, 実証試験スケール微粉炭燃焼炉のLarge-eddy simulation -混焼方式がNO生成に与える影響-, 粉体工学会第53回夏期シンポジウム, 2017.09. |
| 53. |
チョウイ, 渡邊裕章, 北川敏明, 乱流中における粒子分散に関する考察, 粉体工学会第53回夏期シンポジウム, 2017.09. |
| 54. |
渡邊 裕章, チョウ イ, 泰中 一樹, AHN SEONGYOOL, 北川 敏明, 粒子形状が気流中粒子分散挙動に及ぼす影響, 粉体工学会 2017年度春期研究発表会, 2017.05. |
| 55. |
Masaya Muto, Hiroaki Watanabe, Ryoichi Kurose, Large eddy simulation of pulverized coal combustion in multi-burner system -Effect of in-furnace blending method on NOx emission-, The First Asian Conference on Thermal Science, ACTS2017, 2017.03, 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.. |
| 56. |
渡邊 裕章, 丹野 賢二, 黒瀬 良一, 噴流床ガス化炉における石炭ガス化のラージ・エディ・シミュレーション, 第30回数値流体力学シンポジウム, 2016.12. |
| 57. |
渡邊 裕章, チョウ イ, 北川 敏明, 微粉炭粒子着火プロセスの数値シミュレーション, 第22回流動化・粒子プロセッシングシンポジウム, 2016.12. |
| 58. |
チョウ イ, 渡邊 裕章, 北川 敏明, 一様流中を自由運動する単一粒子の着火の数値計算, 第54回燃焼シンポジウム, 2016.11. |
| 59. |
山下 晃弘, 橋本 望, 渡邊 裕章, 藤田 修, Chemical Reactor Networkモデルを用いたCO2回収型高効率IGCCシステムのガスタービンを対象とした燃焼特性の予測, 第54回燃焼シンポジウム, 2016.11. |
| 60. |
森田 理喜, 福田 洋介, 永野幸秀, 渡邊 裕章, 北川 敏明, 乱れのスケールが希薄・EGR 条件下の火炎伝播特性に及ぼす影響, 第54回燃焼シンポジウム, 2016.11. |
| 61. |
Kenji Tanno, Seongyool Ahn, Hisao Makino, Hiroaki Watanabe, Numerical study of effect of operation condition for coal gasifier in oxo-fuel IGCC, The First Austrian-Japan Symposium on Carbon Resource Utilization, 2016.11. |
| 62. |
チョウ イ, 渡邊 裕章, 北川 敏明, 拡張CPDモデルと気相詳細反応モデルとのカップリングによる石炭熱分解挙動数値解析, 第53回石炭科学会議, 2016.10, 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.. |
| 63. |
Hiroaki Watanabe, Akihiro Yamashita, Nozomu Hashimoto, Isao Yuri, Hiroyuki Hishida, Numerical simulation of atmospheric combustion of gasified fuel from oxy-fuel IGCC system, 36th International Symposium on Combustion, 2016.08, 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.. |
| 64. |
Seongyool Ahn, Hiroaki Watanabe, Kenji Tanno, Numerical analysis of formation and decomposition behavior of PAH species in a pulverized coal jet flame with an elementary kinetic mechanism, 36th International Symposium on Combustion, 2016.08, 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.. |
| 65. |
Wei Zhang, Hiroaki Watanabe, Toshiaki Kitagawa, Direct numerical simulation of ignition of a single particle freely moving in a uniform flow, 36th International Symposium on Combustion, 2016.08, 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.. |
| 66. |
Hiroaki Watanabe, Kenji Tanno, Ryoichi Kurose, Large-eddy simulation of coal gasification on a two-stage entrained flow coal gasifier, European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016), 2016.06, 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.. |
| 67. |
Masaya Muto, Hiroaki Watanabe, Ryoichi Kurose, Satoru Komori, Effect of fuel ratio of bituminous coals on pulverized coal combustion in multi-burner system using large-eddy simulation, European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016), 2016.06, 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.. |
| 68. |
林 潤, 渡邊 裕章, 黒瀬 良一, 赤松 史光, 層流対向流場に形成される n-decane 噴霧火炎中のすす生成特性に噴霧特性が与える影響, 第53回日本伝熱シンポジウム, 2016.05, 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.. |
| 69. |
林 潤, 橋本 望, 中塚 記章, 泰中 一樹, 梅本 賢, 渡邊 裕章, 赤松 史光, 牧野 尚夫, 同軸噴流バーナ上に形成される微粉炭火炎中のすす生成特性, 第53回日本伝熱シンポジウム, 2016.05, 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.. |
| 70. |
Nagano Yukihide, Yosuke Fukuda, Akira Noomo, Taiki Tsukamoto, Hiroaki Watanabe, Toshiaki Kitagawa, Study on Spherically Propagating i-C8H18 Turbulent Flames using lean and EGR Conditions using Constant Volume Vessel, The First Pacific Rim Thermal Engineering Conference, PRTEC, 2016.03. |
| 71. |
Nozomu Hashimoto, Jun Hayashi, Noriaki Nakatsuka, Kazuki Tainaka, Satoshi Umemoto, Hirofumi Tsuji, Fumiteru Akamatsu, Hiroaki Watanabe, Hisao Makino, Primary soot particle diameter distributions in a combustion field formed by 4kW pulverized coal jet burner measured by TIRE-LII, The First Pacific Rim Thermal Engineering Conference, PRTEC, 2016.03. |
| 72. |
高橋 弥楊, 橋本 望, 渡邊 裕章, 黒瀬 良一, 藤田 修, 非定常微粉炭燃焼数値解析における揮発分放出モデルの高度化, 日本機械学会北海道支部第45回学生員卒業研究発表講演会, 2016.03. |
| 73. |
Hiroaki Watanabe, Masaya Muto, Ryoichi Kurose, Large-eddy simulation of pulverized coal combustion and gasification on semi-industrial furnaces, 11th Korea-Japan CFD Workshop (KJCFD2015), 2015.12. |
| 74. |
チョウ イ, 丹野 賢二, 武藤 昌也, 渡邊 裕章, 北川 敏明, 一様等方性乱流場において粒子形状が粒子の分散挙動に与える影響, 第29回数値流体力学シンポジウム, 2015.12. |
| 75. |
勝盛 俊平, 出口 祥啓, 生友 章裕, 泰中 一樹, 丹野 賢二, 渡邊 裕章, レーザ誘起ブレークダウン法を用いた石炭灰組成計測技術, 先端計測技術の応用展開に関するシンポジウム, 2015.12. |
| 76. |
山内 智暉, 渡邊 裕章, 北川 敏明, 3-feedシステム非予混合燃焼場のFlameletモデリング, 第53回燃焼シンポジウム, 2015.11, 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.. |
| 77. |
泰中 一樹, 丹野 賢二, 渡邊 裕章, 神本 崇博, 中川 真人, 出口 祥啓, 黒瀬 良一, CT波長可変半導体レーザ吸収分光法による定格3kg/h微粉炭専焼燃焼場に対する2次元温度分布の時系列計測, 第53回燃焼シンポジウム, 2015.11, 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.. |
| 78. |
中川 真人, 出口 祥啓, 神本 崇博, 泰中 一樹, 丹野 賢二, 渡邊 裕章, 黒瀬 良一, 微粉炭燃焼場におけるCT半導体レーザ吸収法を用いた二次元温度分布計測, 第53回燃焼シンポジウム, 2015.11, 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.. |
| 79. |
渡邊 裕章, 丹野 賢二, 梅津 宏紀, 梅本 賢, 黒瀬 良一, 噴流床石炭ガス化炉のlarge-eddy simulation, 日本機械学会 2015年度年次大会, 2015.09, 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.. |
| 80. |
若松 裕紀, 渡邊 裕章, 井上 洋平, 前川 博, 渦と壁面との干渉によって発生する音響場と非定常壁面せん断応力, 日本機械学会 2015年度年次大会, 2015.09, 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.. |
| 81. |
Wei Zhang, Hiroaki Watanabe, Masaya Muto, Kotaro Hori, Toshiaki Kitagawa, Investigation of the motion of a particle with irregular shapes in a uniform flow by direct numerical simulation, 5th International Conference on the Characteristics and Control of Interfaces for High Quality Advanced Materials and 51st Summer Symposium on Powder Technology, 2015.07, 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.. |
| 82. |
渡邊 裕章, 河井 辰彦, S.-Y. Ahn, フレームレットモデルによる石炭ガス化ガス火炎内のNOx生成予測, 第52回日本伝熱シンポジウム, 2015.06. |
| 83. |
丹野 賢二, 渡邊 裕章, 等方性乱流場中における固体燃焼の直接数値計算, 第52回日本伝熱シンポジウム, 2015.06. |
| 84. |
Seongyool Ahn, Kenji Tanno, Hiroaki Watanabe, Generation of a reduced chemical kinetic mechanism for coal combustion, 40th International Technical Conference on Clean Coal & Fuel Systems, 2015.06, 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.
. |
| 85. |
武藤 昌也, 渡邊 裕章, 黒瀬 良一, 小森 悟, 実用スケール微粉炭燃焼炉のLarge-Eddy Simulation, 粉体工学会 2015年度春期研究発表会, 2015.05. |
| 86. |
H. Watanabe, T. Kawai, S.-Y. Ahn, Numerical simulation of NOx formation in syngas combustion, 15th International Conference on Numerical Combustion, 2015.04, 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.. |
| 87. |
S.-Y. Ahn, H. Watanabe, K. Tanno, N. Hashimoto, Application of a skeletal kinetic mechanism of LES of a pulverized coal jet flame, 15th International Conference on Numerical Combustion, 2015.04. |
| 88. |
梅津 宏紀, 渡邊 裕章, 梶谷 史朗, 梅本 賢, Drop Tube Furnace内の微粉炭チャー燃焼シミュレーション, 第20回流動化・粒子プロセッシングシンポジウム, 2014.12. |
| 89. |
丹野 賢二, 渡邊 裕章, 等方性乱流場における乱流の固気反応特性に及ぼす影響, 第28回数値流体力学シンポジウム, 2014.12. |
| 90. |
S.-Y. Ahn, K. Tanno, N. Hashimoto, H. Watanabe, Large eddy simulation of a pulverized coal jet flame with a skeletal kinetic mechanism, 第28回数値流体力学シンポジウム, 2014.12. |
| 91. |
若松 裕紀, 渡邊 裕章, ローパスフィルタのカットオフ波数が衝撃波捕獲に及ぼす影響, 第28回数値流体力学シンポジウム, 2014.12. |
| 92. |
橋本 望, 林 潤, 中塚 記章, 泰中 一樹, 梅本 賢, 辻 博文, 赤松 史光, 渡邊 裕章, 牧野 尚夫, 時間分解レーザ誘起赤熱法による小型微粉炭ジェットバーナ燃焼場のすす1次粒子径分布計測, 第52回燃焼シンポジウム, 2014.12, 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.. |
| 93. |
出口 祥啓, 勝盛 俊平, 生友 章裕, 渡邊 裕章, 泰中 一樹, 黒瀬 良一, レーザ誘起ブレークダウン法を用いた灰中未燃分及び重金属成分計測, 第52回燃焼シンポジウム, 2014.12. |
| 94. |
渡邊 裕章, 武藤 昌也, 黒瀬 良一, 実用スケール微粉炭燃焼炉のLarge-Eddy Simulation, 第52回燃焼シンポジウム, 2014.12. |
| 95. |
若松 裕紀, 渡邊 裕章, 空力音の陽的DNSに与えるconservativeフィルタの影響, 2014年度日本流体力学会年会, 2014.09. |
| 96. |
張 イ, 武藤 昌也, 堀 高太郎, 渡邊 裕章, 気流中の単一非球形粒子運動の直接数値計算, 2014年度日本流体力学会年会, 2014.09, 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.. |
| 97. |
武藤昌也, 渡邊 裕章, 黒瀬良一, 小森悟, S. Balusamy, S. Hochgreb, 微粉炭旋回噴流火炎のLarge-Eddy Simulation -酸化剤酸素濃度がNOx生成に及ぼす影響-, 日本機械学会関西支部第89期定時総会講演会, 2014.03. |
