研究者詳細 - 坪井　伸幸

口頭発表・ポスター発表等 - 坪井　伸幸

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強度可変酸化剤流旋回型ハイブリッドロケットにおける酸化剤軸・接線噴射の非定常数値解析

後藤祥太, 小澤晃平, 宇崎友規, 西川佳希, 坪井伸幸

日本機械学会九州支部講演論文集

加速度環境におけるワックス燃料の境界層燃焼可視化実験へ向けた着火方法の検討

吉野拓郎, 小澤晃平, 坪井伸幸

日本機械学会九州支部講演論文集

二成分Lennard－Jones流体における対応状態原理の成立性

髙橋竜二, 坪井伸幸, 徳増崇, 津田伸一

日本機械学会九州支部講演論文集

酸水素混合系の音速に対する古典的混合則の精度検証

髙橋竜二, 坪井伸幸, 徳増崇, 津田伸一

年次大会

開催期間： 2018年01月記述言語：日本語

In the computational fluid dynamics (CFD) analyses for the combustion chamber of typical liquid rocket engine, for the prediction of thermophysical properties of mixture system, classical mixing rule (CMR) is applied to cubic equation of state (EOS) for single-component. However, the validation of CMR has been hardly conducted because of few experimental data. Therefore, we have conducted the validation of CMR coupled with the Soave–Redlich–Kwong (SRK) EOS as one of the cubic EOSs for the sound speed of oxygen-hydrogen mixture system in supercritical state using molecular dynamics (MD) simulation with the NVEPG ensemble. We have validated the accuracy of CMR through the comparison of the sound speed obtained by MD simulations with that obtained by CMR coupled with the SRK EOS. As a result, we confirmed that the sound speed obtained from SRK EOS coupled with CMR corresponded with that obtained from MD simulations. Further, the relative difference in sound speed between the MD simulations and SRK EOS hardly increased against single-component fluids. This result indicates that the CMR can be applied for the sound speed of oxygen–hydrogen mixture system in supercritical condition.

CiNii Article

実験によるCH4/O2デトネーションの伝播限界に当量比が与える影響の調査

井上卓, 吉田啓祐, 森井雄飛, 村上清人, 坪井伸幸, 林光一

日本機械学会九州支部講演論文集

再使用観測ロケットの空力特性に関する数値解析及び風洞試験

西川佳希, 牟田智幸, 坪井伸幸, 伊藤隆, 野中聡

日本機械学会九州支部講演論文集

二次元数値解析によるローテーティングデトネーションエンジンの内部流れ場の解明：非理想形噴射口の影響調査

塚本真章, 江藤成一朗, 坪井伸幸, 小島孝之, 林光一

日本機械学会九州支部講演論文集

オービターを搭載したWaveriderの空力特性に関する数値解析及び風洞試験

宇崎友規, 牟田智幸, 坪井伸幸, 丸祐介, 藤田和央

日本機械学会九州支部講演論文集

Mixing Characteristics of a Recessed Coaxial Jet at Supercritical Pressure

Daiki Muto, Hiroshi Terashima, Nobuyuki Tsuboi

AIAA SciTech2016

高圧水素噴流の拡散過程の３次元数値解析

藤本啓佑, 武藤大貴, 坪井伸幸, 朝原誠

流体工学部門講演会講演論文集

開催期間： 2016年01月記述言語：日本語

Three-dimensional numerical simulation of high pressure hydrogen jet is performed. Hydrogen leakage from the high pressure hydrogen tank has a possibility of serious explosion accidents. Therefore, it is necessary to understand diffusion behavior and ignition characteristics of hydrogen leakage. The present study simulates the high-pressure hydrogen supersonic free jet into the atmosphere to understand the dispersion process. As a result, the Jet flow fluctuates greatly in the radial direction and hydrogen disperses in a wide sphere. Also, lambda vortex structure was found to perform a crucial function in the diffusion of hydrogen.

CiNii Article

液体燃料ロケットタンク破壊時の推進剤ジェット・主流の干渉メカニズムに関する数値解析

岩佐聡洋, 武藤大貴, 藤本圭一郎, 坪井伸幸

年次大会

開催期間： 2016年01月記述言語：日本語

Numerical simulations of the jet injected into supersonic cross-flow are carried out. In aborting process in liquid rocket flight, the fuel is transversely injected into the supersonic freestream. Developed jet/freestream interaction structure may trigger unexpected auto-ignition or explosion events; thus the understanding of the flow-field of jet-in-supersonic cross-flow is essential to meet the reliability of rocket. The two-dimensional numerical simulations are carried out in a wide-range of jet and freestream conditions: the jet-to-freestream momentum flux ratio and the pressure ratio. Present result shows recirculation regions are formed both at the upstream and downstream of injector with the characteristic vortex structures. With increasing the jet-to-freestream momentum flux ratio, the vortex structures in the recirculation region are largely developed. It is founded that the highest temperature in the separation region depends on the total temperature in the separation region and furthermore, it is the lower temperature than the total temperature of freestream.

CiNii Article

Aerodynamic Characteristics Study on Waverider for Applying to TSTO

Tomoyuki Muta, Haruka Etoh, Nobuyuki Tsuboi, Yusuke Maru, Kazuhisa Fujita

30th International Symposiumon Space Technokigy and Science

Characteristics of Jet-Mixing at Supercritical Pressure for Coaxial Rocket Injector Design

Daiki Muto, Nobuyuki Tsuboi, Hiroshi Terashima

30th International Symposiumon Space Technokigy and Science

Evaluation of Thrust Performance on Rotating Detonation Engine for a JP10-Air Mixture

Wataru Yoshida, Makoto Asahara, Nobuyuki Tsuboi, A.Koichi Hayashi

30th International Symposiumon Space Technokigy and Science

Effects of the Recess Length on Supercritical Jet Mixing of Co-planar/axial Injectors

Daiki Muto, Nobuyuki Tsuboi, Hiroshi Terashima

6th European Conference forAeronautics and Space Sciences(EUCASS 2015)

Effects of Injector Geometry on Co-Flowing Planar Jet Mixings under Supercritical Pressures

Daiki Muto, Nobuyuki Tsuboi, Hiroshi Terashima

AIAA SciTech2015

Near propagation limit behavior of CH4/O2 Detonation in round tube:influence of equivalent ratio and tube diameter

Keisuke Yoshida, Koichi Hayashi, Youhi Morii, Kiyoto Murakami, Akio Susa, Nobuyuki Tsuboi A. Koichi Hayash

The 5th International symposium on Energetic Materials and their applications

Numerical simulation of thrust performance estimation on rotating detonation engine : The effects of nozzle on Isp

Yusuke WATANABE, Seiichiro ETOH, Nobuyuki TSUBOI, Takayuki KOJIMA, A. Koichi HAYASH

The 5th International symposium on Energetic Materials and their applications

Interaction between Shock Wave and Spherical Flme in Ethylene/Air Mixture and Transition to Detonation

Takayuki Araki, Youhi Morii, Nobuyuki Tsuboi, Koichi A. Hayashi

The 5th International symposium on Energetic Materials and their applications

Numerical Simulation on Unsteady Compressible Low-Speed Shear Flow in Hybrid Rocket Combustion Chamber Using Preconditioned Method: Effects of Preconditioned Method Including Multi-Species Mass Conservation Equations

Nobuyuki Tsuboi

Eleventh International Conference on Flow Dynamics

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口頭発表・ポスター発表等 - 坪井 伸幸

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口頭発表・ポスター発表等 - 坪井　伸幸