| Chihiro Inoue | Last modified date：2023.06.24 |
Associate Professor /
Department of Aeronautics and Astronautics /
Faculty of Engineering
Papers
| 1. | Tenshiro Ichimura, Chihiro Inoue, Zhenying Wang, George Kuwabara, Kenji Tahara, In-situ 1-kHz real-time particle tracking velocimetry using high-speed streaming camera, Flow Measurement and Instrumentation, https://doi.org/10.1016/j.flowmeasinst.2023.102361, Published Online:23 March 2023, 2023.03, [URL].  |
| 2. | Yuki Oishi, Soma Tauchi, Chihiro Inoue, Unsteady Stream-Tube Model for Pulse Performance of Bipropellant Thrusters, Journal of Propulsion and Power, https://doi.org/10.2514/1.B38793, 39, 1, 3-10, 2023.01, [URL]. |
| 3. | Takuya Inoue, Yoshiaki Kamada, Chihiro Inoue and Zhenying Wang, Parametric analysis of interfacial friction factor for liquid film dynamics sheared by turbulent gas flow, Int. J. Gas Turbine, Prop. and Power, https://doi.org/10.38036/jgpp.13.3_1, 13, 3, 2022.11. |
| 4. | Wataru Hikita, Shodai Hirayama, Chihiro Inoue, Zhenying Wang, Makoto Nakaseko, Takuya Takashita, Fragmentation and solidification of fusible alloy melt by water spray, Powder Technology, https://doi.org/10.1016/j.powtec.2022.117778, 409, 117778, 2022.09. |
| 5. | Taro KIMURA and Chihiro INOUE, Analysis on bursting mechanism of carbon steel sparks, Science and Technology of Energetic Materials, 10.34571/stem.83.3_95, 83, 3, 95-101, 2022.07. |
| 6. | Takuya Inoue, Chihiro Inoue, Go Fujii and Yu Daimon, Evaporation of Three-Dimensional Wavy Liquid Film Entrained by Turbulent Gas Flow, AIAA Journal, https://doi.org/10.2514/1.J061381, 60, 6, 3805-3812, Received18 October 2021 Accepted24 December 2021 Published online2 February 2022, 2022.06, [URL], 高温の燃焼ガスによる強制対流熱伝達からロケットエンジン燃焼室を保護するために，冷却液膜が使用される．液膜のドライアウト点の予測は設計開発上重要であるが，困難な課題であった．本研究では，液膜のドライアウト点の理論的予測に初めて成功し，実機エンジン燃焼試験との比較を通じて，その妥当性を検証した．. |
| 7. | Gautier Verhille, Chihiro Inoue, and Emmanuel Villermaux, Architecture of a self-fragmenting droplets cascade, Physical Review E, https://doi.org/10.1103/PhysRevE.104.L053101, 104, L053101, 2021.11. |
| 8. | Go Fujii, Yu Daimon, Katsumi Furukawa, Chihiro Inoue, Daijiro Shiraiwa, and Nobuhiko Tanaka, Visualization of Coolant Liquid Film Dynamics in Hypergolic Bipropellant Thruster, Journal of Propulsion and Power, https://doi.org/10.2514/1.B38421, Published Online:16 Sep 2021, 2021.09. |
| 9. | Wataru Hikita, Tenchiro Ichimura, Chihiro Inoue, Makoto Nakaseko, Visualization and modeling for water atomization of low melting point alloy, Advanced Powder Technology, Accepted on Sep.17, 2021, 2021.09, 金属積層技術が広く使用される昨今の状況にあって，金属粉末の製造技術の高度化が強く期待されている．本研究は，溶融金属に高速の水噴霧を衝突させる水アトマイズ法を対象に，高速度カメラを用いて金属粉末の生成プロセスを明らかにすることに初めて成功した．. |
| 10. | Chihiro Inoue, Yuki Oishi, Yu Daimon, Go Fujii, and Kaname Kawatsu, Direct Formulation of Bipropellant Thruster Performance for Quantitative Cold-Flow Diagnostic, Journal of Propulsion and Power, https://doi.org/10.2514/1.B38310, Published Online:14 Jul 2021, 2021.07. |
| 11. | Taro KIMURA and Chihiro INOUE, Analysis on unsteady thermal behavior of ground iron sparks, Science and Technology of Energetic Materials, https://doi.org/10.34571/stem.82.2_50, 82, 2, 50-55, 2021.05. |
| 12. | Chihiro Inoue, Hiroaki Yoshida, Junya Kouwa, Yuki Iwaki and Mitsunori Itoh, Measurement and Modeling of Planar Airblast Spray Flux Distributions, International Journal of Multiphase Flow, 10.1016/j.ijmultiphaseflow.2021.103580, 137, 2021.04. |
| 13. | Chihiro Inoue and Ikkan Maeda, On the droplet entrainment from gas-sheared liquid film, Physics of Fluids, doi: 10.1063/5.0038399, 33, 1, 011705, 2021.01. |
| 14. | Chihiro INOUE, Ryo NISHIYAMA, Yasuhiro FUJISAKI, Toshiaki KITAGAWA, Senko-Hanabi under Various Ambient Conditions, Science and Technology of Energetic Materials, 2020.04. |
| 15. | Yuto Terauchi, Chihiro Inoue, Yu Daimon, Go Fujii, Proposal of Specific Impulse Prediction Method for Bipropellant Thruster, Trans. Japan Soc. Aero. Space Sci., 2020.04. |
| 16. | Chihiro INOUE,Taiki WATANABE and Yuzo INOKUCHI, Heat Balance of Senko-hanabi and Iron Sparks, Science and Technology of Energetic Materials, 2019.06. |
| 17. | Chihiro INOUE, Yuta TAKEUCHI, Koji NOZAKI, Takehiro HIMENO, Toshinori WATANABE, Go FUJII,and Yu DAIMON, Unified Length Scale of Spray Structure by Unlike Impinging Jets, Trans. Japan Soc. Aero. Space Sci., 2019.03. |
| 18. | Chihiro INOUE，Yu-ichiro IZATO，Atsumi MIYAKE, and Mitsuo KOSHI, Bubble Growth in Non-Evaporative Drops of “Senko-hanabi”, Science and Technology of Energetic Materials, 2019.03. |
| 19. | Chihiro Inoue, Yuta Takeuchi, Koji Nozaki, Takehiro Himeno, Toshinori Watanabe, Go Fujii, Yu Daimon, Unified length scale of spray structure by unlike impinging jets, Transactions of the Japan Society for Aeronautical and Space Sciences, 10.2322/tjsass.62.213, 62, 4, 213-218, 2019.01, In bi-propellant thrusters, impinging type injectors are widely used to deliver propellants to a combustion chamber. By impinging the jet streams of fuel and oxidizer, the spray spreads while the two liquids mix. To design the injectors, several correlations related to injection conditions have been proposed (e.g., Rupe factor), and practically utilized over the last half-century. However, the physical meanings of the past correlations are not well understood, because the essential scale of the spray structure is elusive. In this paper, we derive the global length scale of the spray produced by impinging injectors of unlike doublet, fuel-oxidizer-fuel triplet, and oxidizer-fuel-oxidizer triplet in a consistent manner. The unified length scale is found representing the spray width ratio of oxidizer to fuel evidenced by comprehensive cold-flow tests including several past studies, covering various parameters such as injector types, nozzle diameters, physical properties of working liquids, and injection velocities. Finally, we clearly provide the physical meaning based on practical correlations in a phenomenological sense.. |
| 20. | Toshinori Watanabe, Toshihiko Azuma, Seiji Uzawa, Takehiro Himeno, Chihiro Inoue, Unsteady pressure measurement on oscillating blade in transonic flow using fast-response pressure- sensitive paint, Journal of Turbomachinery, 10.1115/1.4039180, 140, 6, 2018.05, A fast-response pressure-sensitive paint (PSP) technique was applied to the measurement of unsteady surface pressure of an oscillating cascade blade in a transonic flow. A linear cascade was used, and its central blade was oscillated in a translational manner. The unsteady pressure distributions of the oscillating blade and two stationary neighbors were measured using the fast-response PSP technique, and the unsteady aerodynamic force on the blade was obtained by integrating the data obtained on the pressures. The measurements made with the PSP technique were compared with those obtained by conventional methods for the purpose of validation. From the results, the PSP technique was revealed to be capable of measuring the unsteady surface pressure, which is used for flutter analysis in transonic conditions.. |
| 21. | Takehiro Himeno, Akifumi Ohashi, Keitaro Anii, Daichi Haba, Yasunori Sakuma, Toshinori Watanabe, Chihiro Inoue, Yutaka Umemura, Hideyo Negishi, Satoshi Nonaka, Investigation on phase change and pressure drop enhanced by violent sloshing of cryogenic fluid, 54th AIAA/SAE/ASEE Joint Propulsion Conference, 2018 2018 Joint Propulsion Conference, 10.2514/6.2018-4755, 2018.01, For the prediction of heat transfer coupled with sloshing phenomena in the propellant tanks of reusable launch vehicle for sounding mission, the pressure drop induced by heat transfer and the dynamic motion of liquid in sub-scale vessels were experimentally investigated. The correlation between the pressure drop and liquid motion was confirmed in the experiment. It was suggested that splash and wavy surface induced by violent motion of liquid cause the pressure drop in the closed vessel. In addition, as the preliminary investigation, non-isothermal sloshing of liquid nitrogen and liquid hydrogen were successfully visualized and pressure drop depending on the gaseous species was discussed.. |
| 22. | Chihiro Inoue, Go Fujii, Yu Daimon, Mixing length scale of Bi-propellant thrusters for characteristic velocity formulation, International Journal of Energetic Materials and Chemical Propulsion, 10.1615/IntJEnergeticMaterialsChemProp.2018025085, 16, 3, 281-294, 2017.12, Bi-propellant thrusters in space propulsion systems often utilize unlike-doublet or triplet injectors as the hypergolic propellant injection device. The impingement of liquid jet streams of fuel and oxidizer involves sheet expansion, droplet fragmentation, mixing, evaporation, and chemical reactions in liquid and gas phases. In the sequential reactive, multiphase, thermo-fluid dynamics, the rate controlling phenomenon is the mixing step. In this study, a defined length scale demonstrates the distribution of fuel and oxidizer and thus represents their mixing states, facilitating the straightforward formulation of characteristic velocity in a consistent manner for doublet and triplet injectors as a function of propellant injection conditions with a film cooling effect. The validity of the present modeling framework is confirmed by a good agreement with characteristic velocity measured by hot firing tests covering a wide range of the mixture ratio. We also clarify the meaning of a widely accepted practical indicator, the so-called Rupe factor, over half a century of injector design history.. |
| 23. | Chihiro Inoue, Yu Ichiro Izato, Atsumi Miyake, Emmanuel Villermaux, Direct Self-Sustained Fragmentation Cascade of Reactive Droplets, Physical Review Letters, 10.1103/PhysRevLett.118.074502, 118, 7, 2017.02, A traditional hand-held firework generates light streaks similar to branched pine needles, with ever smaller ramifications. These streaks are the trajectories of incandescent reactive liquid droplets bursting from a melted powder. We have uncovered the detailed sequence of events, which involve a chemical reaction with the oxygen of air, thermal decomposition of metastable compounds in the melt, gas bubble nucleation and bursting, liquid ligaments and droplets formation, all occurring in a sequential fashion. We have also evidenced a rare instance in nature of a spontaneous fragmentation process involving a direct cascade from big to smaller droplets. Here, the self-sustained direct cascade is shown to proceed over up to eight generations, with well-defined time and length scales, thus answering a century old question, and enriching, with a new example, the phenomenology of comminution.. |
| 24. | Chihiro Inoue, Junya Kouwa, Toshinori Watanabe, Takehiro Himeno, Seiji Uzawa, Shinsuke Matsuno, Normalized spray flux distribution in impinging atomization, Transactions of the Japan Society for Aeronautical and Space Sciences, 10.2322/tjsass.60.255, 60, 4, 255-258, 2017.01, A simple method of determining normalizing spray flux distribution was demonstrated applying flow visualization and the measurement of droplet distribution using a patternator. Two reservoirs are used to contain the working fluid (water) under pressure. This liquid is injected into still air from two nozzles. The nozzles are adjustable to eliminate any misalignment of the water jets. The surface tension coefficient was measured using an automatic surface tensiometer employing the plate method. The atomization process was visualized using a high-speed video camera in conjunction with a backlighting technique. The 3D-printed patternator was demonstrated to be useful for the 2D measurement of spray mass flux distributions. The spray mass flux distribution was normalized as a function of normalized distance after atomization was complete. The flux distribution at any location could be calculated from the normalized distribution convergence considering the spread of the spray.. |
| 25. | Chihiro Inoue, Asian joint conference on propulsion and power (AJCPP2016), Explosion, 26, 2, 128-130, 2016.01. |
| 26. | Chihiro Inoue, Mitsuo Koshi, Takehiro Himeno, Toshinori Watanabe, Investigation on liquid atomization mechanism in Japanese sparkler "Senko-hanabi, Science and Technology of Energetic Materials, 77, 3-4, 51-58, 2016.01, Sparkling firework, which is a Japanese sparker called Senko-hanabi, is composed of black powder containing no metal wrapped in a twisted paper. The firework has a unique beauty with streaks of light similar to the pine needles. For over 300 years, however, physics behind the beauty of the firework is hidden mystery. In this study, detailed high-speed visualization measurements are conducted to quantify the individual stages in the life of sparkling firework. It is confirmed that the droplets, which will be the streaks of light, are formed from liquid atomization induced by bursting of the fireball itself or the bubbles on the surface. The rupture process of non-evaporative droplets is successfully captured, and it is determined that the bursting of a droplet is caused by microexplosion, which is the sudden expansion of gas produced inside the droplet.. |
| 27. | J. Kouwa, S. Matsuno, C. Inoue, T. Himeno, T. Watanabe, Free-surface Flow Simulation of Unlike-doublet Impinging Jet Atomization, 20th Australasian Fluid Mechanics Conference, AFMC 2006 Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2006, 2016.01, In liquid-propellant chemical propulsion systems, the liquid fuel and oxidizer are atomized by impinging jet atomization, mixed and combustions will occur due to auto-ignition inside a chamber. It is important for a performance prediction to simulate the primary atomization phenomenon; especially, the local mixture ratio can be used as indicator of thrust performance, so it is useful to evaluate it from numerical simulations. In this research, to predict local mixture ratio distribution downstream from an impingement point, we propose a numerical method for considering bi-liquid and the mixture and install it to CIP-LSM which is a two-phase flow simulation solver with level-set and MARS method as an interfacial tracking method. A new parameter, β, which is defined as the volume fraction of one liquid in the mixed liquid within a cell is introduced and the solver calculates the advection of β, inflow and outflow flux of β to a cell. SMART method is used for the interpolating value in a cell. By validating this solver, we conducted a simple experiment and the same simulation. From the result, the solver can predict the penetrating length of a liquid jet correctly and it is confirmed that the solver can simulate the mixing of liquids. Then we apply this solver to the numerical simulation of impinging jet atomization. From the result, the inclination angle of fan after the impingement in the bi-liquid condition reasonably agrees with the theoretical value. Also, it is seen that the mixture of liquids can be simulated in this result. We validate the numerical method by comparing numerical results with the experimental results with local mass flux and mixture ratio distributions.. |
| 28. | J. Kouwa, S. Matsuno, C. Inoue, T. Himeno, T. Watanabe, Free-surface Flow Simulation of Unlike-doublet Impinging Jet Atomization, 20th Australasian Fluid Mechanics Conference, AFMC 2006 Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2006, 2016.01, In liquid-propellant chemical propulsion systems, the liquid fuel and oxidizer are atomized by impinging jet atomization, mixed and combustions will occur due to auto-ignition inside a chamber. It is important for a performance prediction to simulate the primary atomization phenomenon; especially, the local mixture ratio can be used as indicator of thrust performance, so it is useful to evaluate it from numerical simulations. In this research, to predict local mixture ratio distribution downstream from an impingement point, we propose a numerical method for considering bi-liquid and the mixture and install it to CIP-LSM which is a two-phase flow simulation solver with level-set and MARS method as an interfacial tracking method. A new parameter, β, which is defined as the volume fraction of one liquid in the mixed liquid within a cell is introduced and the solver calculates the advection of β, inflow and outflow flux of β to a cell. SMART method is used for the interpolating value in a cell. By validating this solver, we conducted a simple experiment and the same simulation. From the result, the solver can predict the penetrating length of a liquid jet correctly and it is confirmed that the solver can simulate the mixing of liquids. Then we apply this solver to the numerical simulation of impinging jet atomization. From the result, the inclination angle of fan after the impingement in the bi-liquid condition reasonably agrees with the theoretical value. Also, it is seen that the mixture of liquids can be simulated in this result. We validate the numerical method by comparing numerical results with the experimental results with local mass flux and mixture ratio distributions.. |
| 29. | Chihiro Inoue, Mitsuo Koshi, Hiroshi Terashima, Takehiro Himeno and Toshinori Watanabe, Origin of Droplets in Sparkling Fireworks, Science and Technology of Energetic Materials, 2013.08. |
| 30. | Takehiro Himeno, Daichi Haba, Katsutoshi Ishikawa, Yutaka Umemura, Chihiro Inoue, Seiji Uzawa, Toshinori Watanabe, Satoshi Nonaka, Experimental investigation on heat exchange and pressure drop enhanced by vertical sloshing, 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, JPC 2013 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 10.2514/6.2013-3906, 2013.01, For the prediction of heat transfer coupled with sloshing in the propellant tanks of launch vehicle, the pressure drop induced by liquid motion in a sub-scale vessel excited in vertical direction was experimentally investigated. The strong correlation between the pressure drop and liquid motion was confirmed in the experiment. The mechanisms enhancing heat transfer were discussed based on the visualization. It was suggested that shear flow and vortices induced by violent motion of liquid should cause the pressure drop in the closed vessel.. |
| 31. | Junya Kouwa, Shinsuke Matsuno, Chihiro Inoue, Takehiro Himeno, Toshinori Watanabe, Free-surface flow simulation of impinging jet nozzles for liquid-propellant thrusters, 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, JPC 2013 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 10.2514/6.2013-4069, 2013.01, This paper describes the results obtained by free surface analysis of impinging jet nozzles for a wide range of orifice diameter and jet momentum under non-reactive conditions. The numerical results are compared with experimental results under some conditions. Capability of the present simulation method CIP-LSM to impinging jet atomization is confirmed by comparing the fan-shaped liquid condition after impingement. As a consequence, the present method can simulate the angle of the liquid after the impingement and the impinging modes approximately. The numerical analysis for three sector of simulant thruster is conducted and it is confirmed that interactions between fans are demonstrated.. |
| 32. | Chihiro Inoue, Toshinori Watanabe, Takehiro Himeno, Seiji Uzawa, Impinging atomization enhanced by microjet injection - effect, mechanism and optimization, 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, JPC 2013 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 10.2514/6.2013-3705, 2013.01, Impinging atomization, which has been widely utilized in liquid rocket propulsion systems, is able to produce fine drops at a rated operation. In contrast, the atomization characteristics deteriorate under off design conditions when injection velocity comes to be slower. In the present study, for improving atomization characteristics at off design conditions, an effective technique is verified utilizing small amount of gas (microjet) injection. The microjet is supplied from a pressurized reservoir and is injected from the center of the liquid nozzles toward the impingement point. To clarify the flow field and the mechanism of the effect, experimental visualizations, drop size measurements and corresponding numerical analyses are carried out. It is elucidated that Sauter Mean Diameter (SMD) becomes one-tenth of the original SMD by the microjet injection with the amount of only 1% of liquid mass flow rate. The dominant non-dimensional number is found to be the ratio of the dynamic pressure (microjet/liquid jet) at the impingement point. The optimized atomization efficiency is achieved when the dynamic pressure ratio is approximately two.. |
| 33. | Chihiro Inoue, Toshinon Watanabe, Takehiro Himeno, Seiji Uzawa, Enhancement mechanism of impinging atomization by gas injection, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 10.1299/kikaib.78.1990, 78, 795, 1990-2003, 2012.12, Impinging atomization, which has been widely utilized in liquid rocket propulsion systems, is able to produce fine drops at a rated operation. In contrast, however, the atomization characteristics deteriorate under off design conditions when injection velocity comes to be slower. In the present study, for improving atomization characteristics at off design operation, an effective technique is verified utilizing small amount of gas injection. The gas jet is supplied from a pressurized reservoir independent of the liquid supply system, and it is injected from the center of the liquid nozzles toward the impingement point. To clarify the flow field and the mechanism of the effectivity, experimental visualizations, drop size measurements and corresponding numerical analyses are carried out. It is elucidated that atomization is drastically promoted when the dynamic pressure of gas overcomes that of liquid at the impingement point. By the gas injection with the amount of only 1% of liquid mass flow rate, Sauter Mean Diameter (SMD) becomes one-tenth of the original SMD. In addition, the optimized atomization efficiency is achieved when the gas dynamic pressure is twice as much as the liquid at the impingement point.. |
| 34. | Chihiro Inoue, Toshinori Watanabe, Takehiro Himeno, Atomization and flow characteristics of liquid sheet produced by jet impingement, Journal of Propulsion and Power, 10.2514/1.B34392, 28, 5, 1060-1070, 2012.09, Aimingatelucidating the relationship between a liquid sheet atomization and the detailedflowfield inside the sheet produced by an impingement-type injector, numerical computation, experimental observation, and theoretical analysis were performed. A numerical method was developed to examine atomization phenomena. First, the method was verified through quantitative comparison with a corresponding experiment of pinch off. Then, experimental and theoretical analyses were conducted on the atomization of an axisymmetric liquid sheet through Kelvin-Helmholtztype instability, which was produced by two opposing watexr jets. The numerical results showed qualitative resemblance to the corresponding experimental and theoretical analyses. Finally, it was clarified that a nonuniform injection velocity profile resulted in a velocity distribution with an inflection point inside the sheet. As a result, the sheet tended to be unstable and enhanced atomization.. |
| 35. | Chihiro Inoue, Toshinori Watanabe, Takehiro Himeno, Mitsuo Koshi, Estimation method of spray diameter and size distribution based on energy conservation law, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 10.1299/kikaib.78.850, 78, 788, 850-861, 2012.06, An analytical method was proposed and validated for droplet diameters and size distributions. The method was developed based on the energy conservation law including surface free energy and Laplace pressure. Under several hypotheses, the law derived an equation indicating that atomization resulted from a kinetic energy loss. Thus, once the amount of loss was obtained, the droplet diameter was able to be calculated without any experimental parameters. When the effects of ambient gas were ignorable, injection velocity profiles of liquid jets were the essential factor for the reduction of kinetic energy. The minimum Sauter mean diameter produced by liquid sheet atomization was inversely proportional to the injection Weber number under the conditions of injection velocity profiles with laminar or turbulent. By applying the mean diameter model, a non dimensional distribution function was also derived assuming Nukiyama-Tanasawa's function. The validity of these estimation methods were favorably confirmed by comparisons with corresponding mean diameters and the size distributions, which were experimentally measured under atmospheric pressure.. |
| 36. | Chihiro Inoue, Toshinori Watanabe, Takehiro Himeno, Seiji Uzawa, Effect and mechanism of injector internal flow on liquid sheet dynamics and atomization characteristics (effect of injection velocity profile), Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 10.1299/kikaib.76.765_755, 76, 765, 755-762, 2010.01, Aiming at elucidating the relationship between injector internal flow, especially injection velocity profiles, and atomization characteristics of liquid sheet, experimental measurement, numerical and theoretical analyses were carried out. Liquid space distribution produced by atomization of axisymmetric sheet, which was created by collision of two water jets in opposite direction, was experimentally obtained utilizing paternator. The amplitude of the liquid sheet oscillation was developed based on linear stability analysis. The numerical results of atomization process through Kelvin-Helmholtz type instability showed qualitative resemblance with corresponding experimental results and theoretical analyses. It was clarified that non-uniform injection velocity profile resulted in velocity distribution with inflection point inside the sheet, thus the sheet became unstable and enhanced atomization. The effect of injection velocity profile on atomization at impingement type injector was also clearly represented.. |
| 37. | Takehiro Himeno, Hideyo Negishi, Satoshi Nonaka, Chihiro Inoue, Toshinori Watanabe, Seiji Uzawa, Numerical analysis of free-surface flows under various conditions in acceleration (improvement of CIP-LSM CIP-based level set & MARS), Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 10.1299/kikaib.76.765_778, 76, 765, 778-788, 2010.01, With the progress of human activities in space, the occasion to handle liquids in no-uniform acceleration or low-gravity is now growing. On the launch vehicles with liquid propulsion system, the dynamic acceleration during its powered ascent or ballistic flight makes it very difficult to control the position of propellants in the tanks. For the establishment of the technology for the management of liquid propellant in space vehicles, a numerical method, called 'CIP-LSM' (CIP based Level Set & MARS), was developed to simulate three-dimensional free-surface flows under various gravity conditions, which has been applied to clarify the dynamic behavior of liquid propellant in the tanks of launch vehicles.. |
| 38. | Chihiro Inoue, Toshinori Watanabe, Takehiro Himeno, Numerical analysis on breakup process and inner structure of oscillatory liquid jet, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 73, 12, 2397-2402, 2007.12, In order to obtain fundamental knowledge of liquid breakup phenomena, the three dimensional flow field of oscillatory liquid jet in pinch off was numerically studied by the developed method, CIP-LSM. In the present paper, not only the liquid jet shape but also its inner structure was investigated. The numerical results of liquid shapes and velocity distributions were compared with the corresponding experimental ones. From the results, CIP-LSM was confirmed to have potential to simulate liquid breakup phenomena in which surface tension was predominant. It was revealed that inner structures of the liquid jet were constructed due to the surface tension at the nozzle exit. The jet breakup was demonstrated to occur at the fluid element injected with the minimum acceleration.. |
| 39. | Chihiro Inoue, Toshinori Watanabe, Takehiro Himeno, Numerical study on flow induced vibration of LOX post in liquid rocket engine preburner, International Journal of Gas Turbine, Propulsion and Power Systems, 1, 1, 22-29, 2007.10, In a preburner of liquid rocket engines, some liquid-oxygen (LOX) posts, which introduced oxygen into combustion chamber, experienced severe flow-induced vibration due to unsteady cryogenic hydrogen flow. The mechanism of the vibration has not been fully understood because of the complexity of the flow field. In the present study, a new numerical method was developed to analyze the flow field of hydrogen, whose characteristic properties lie in its non-idealness and compressibility. The unsteady hydrogen flow inside the preburner unit was analyzed to investigate the details of hydrogen flow field as well as the mechanism of LOX post vibration. It was clarified that hydrogen flow inside the manifold and fluid dynamic forces on LOX posts were strongly affected by vortices shed from the junction at the upstream of the inlet. A baffle plate put inside the manifold was shown to reduce unsteady fluid forces on the LOX posts.. |
| 40. | J. Kouwa, S. Matsuno, Chihiro Inoue, T. Himeno, T. Watanabe, Free-surface Flow Simulation of Unlike-doublet Impinging Jet Atomization, 20th Australasian Fluid Mechanics Conference, AFMC 2006 Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2006, 2006.01, In liquid-propellant chemical propulsion systems, the liquid fuel and oxidizer are atomized by impinging jet atomization, mixed and combustions will occur due to auto-ignition inside a chamber. It is important for a performance prediction to simulate the primary atomization phenomenon; especially, the local mixture ratio can be used as indicator of thrust performance, so it is useful to evaluate it from numerical simulations. In this research, to predict local mixture ratio distribution downstream from an impingement point, we propose a numerical method for considering bi-liquid and the mixture and install it to CIP-LSM which is a two-phase flow simulation solver with level-set and MARS method as an interfacial tracking method. A new parameter, β, which is defined as the volume fraction of one liquid in the mixed liquid within a cell is introduced and the solver calculates the advection of β, inflow and outflow flux of β to a cell. SMART method is used for the interpolating value in a cell. By validating this solver, we conducted a simple experiment and the same simulation. From the result, the solver can predict the penetrating length of a liquid jet correctly and it is confirmed that the solver can simulate the mixing of liquids. Then we apply this solver to the numerical simulation of impinging jet atomization. From the result, the inclination angle of fan after the impingement in the bi-liquid condition reasonably agrees with the theoretical value. Also, it is seen that the mixture of liquids can be simulated in this result. We validate the numerical method by comparing numerical results with the experimental results with local mass flux and mixture ratio distributions.. |
| 41. | Yasuro Hirooka, Hiroshi Katsurayama, Koichi Mori, Chihiro Inoue, Kimiya Komurasaki, Yoshihiro Arakawa, Nozzle performance of a RP laser thruster, 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2003 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2003.12, In order to reveal the nozzle scaling law of a Repetitive Pulsed (RP) laser thruster, momentum-coupling coefficients of several conical nozzles were investigated by means of experiment and numerical analysis. In the experiment, a pendulum method was used to measure an impulse imparted to a conical nozzle by a laser-driven blast wave. A propagation of the blast wave in a conical nozzle and an exhaust-refill process were analyzed by CFD. The calculated Cm agreed with the experimental data. The processes until a critical time are qualitatively the same regardless of a divergence angle, but quantitatively different. As a result, the nozzle of a small apex angle enhances the performance of a RP laser thruster when only a single pulse is input.. |
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