論文 - 松尾　亜紀子

Numerical investigation on characteristic lengths for gaseous detonation with dilute water spray

Watanabe H., Matsuo A., Chinnayya A., Matsuoka K., Kawasaki A., Kasahara J.

AIAA Propulsion and Energy Forum and Exposition, 2019 （AIAA Propulsion and Energy Forum and Exposition, 2019）  2019年

ISSN  9781624105906

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© 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Two-dimensional (2D) numerical simulations based on Eulerian-Lagrangian method are conducted to clarify the droplet behavior within its lifetime within the detonation cell. The simulation results are analyzed via 2D instantaneous flow fields and Favre spatiotemporal average technique, by applying the recycling block method. Gaseous detonation with dilute water droplets (WDs) propagates stably with a 4% velocity decrease compared to dry CJ velocity in the simulation conditions. From the instantaneous flow field analysis, the droplet breakup occurs primarily in jets, downstream of the transverse wave, nearby the collision of transverse waves, and the interaction between the transverse wave and the jets. The Favre average one-dimensional profiles by grouping WDs based on the initial shock strength that WDs experience reveal the droplet life inside the cellular structure. The mean equilibrium diameter after the breakup is not affected by the initial shock strength.

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An experimental study of in-space rotating detonation engine with cylindrical configuration

Kawasaki A., Kim J., Yokoo R., Goto K., Matsuoka K., Kasahara J., Matsuo A., Funaki I.

AIAA Propulsion and Energy Forum and Exposition, 2019 （AIAA Propulsion and Energy Forum and Exposition, 2019）  2019年

ISSN  9781624105906

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© 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Utilizing detonation in a combustor potentially leads to a compact and propellant-efficient rocket engine. A rotating detonation engine (RDE) is a form of such detonation engine. For a practical realization of the RDE, maturation of its thermal design is essential. In this study, a miniature cylindrical rotating detonation engine was tested in a low-pressure environment (~ 6 kPa) with a film-cooled wall. For the combustor, measurement of lateral wall temperature and high-speed imaging were conducted during combustion. As a result, it has been clarified that there exist an appropriate range in the coolant flow rate to maintain detonation combustion. Additionally, it has been also clarified that film cooling is effective even under detonation combustion.

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Optical Measurement of Fluid Motion in Semi-Valveless Pulse Detonation Combustor with High-Frequency Operation

Kubota, A., Matsuoka, K., Kawasaki, A., Kasahara, J., Watanabe, H., Matsuo, A., and Endo, T.

Combustion Science and Technology 192 （ 2 ） 197 - 212 2018年12月

研究論文（学術雑誌）, 共著, 査読有り

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Experimental investigation on detonation dynamics through a reactivity sink

Boulal S., Vidal P., Zitoun R., Matsumoto T., Matsuo A.

Combustion and Flame （Combustion and Flame）  196   11 - 25 2018年10月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  00102180

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© 2018 The Combustion Institute This article reports on an experimental investigation into dynamical behaviours of detonation in non-uniform mixtures, generated from stoichiometric propane–oxygen, oxygen and ethane, with initial temperature and pressure 290 K and 20 kPa, respectively. Composition gradients are parallel to the direction of detonation propagation, with an equivalence ratio (ER) that first decreases from lean values and then increases to rich ones. Composition distributions are characterized according to the depth of the ER sink. Gradients are generated in a 50 × 50-mm2-square cross-section and a 665-mm total length chamber. The mixture components are injected separately in the pre-evacuated chamber in their order of decreasing density through porous plates at the chamber top-end to ensure planar filling of the chamber. Non-uniform distributions are then precisely controlled as a function of time by means of optical oxygen sensors. A Chapman–Jouguet (CJ) detonation is transmitted at the chamber bottom-end from a 3.6-m-long driver tube. Fast pressure transducers, sooted plates and Schlieren visualizations coupled with high-speed cameras are used to characterize the longitudinal velocity, cellular structure and transmission, failure and re-initiation mechanisms of the detonation front. Shallowest ER sinks produce the supercritical transmission mode of the CJ detonation with continuous adaptation of velocity and multicellular structure to local composition. Deepest sinks lead to the subcritical behaviour characterized by sudden detonation failure from shock-flame decoupling when ER decreases, and without detonation re-initiation when ER increases again. Intermediate sink depths generate critical behaviour with detonation re-initiat ion at chamber walls from expanding combustion kernels and reflected transverse Mach waves and then from SWACER retro-active mechanism. An elaboration of the failure criterion used in a previous study is found to well predict conditions for shock-flame decoupling.

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Two-dimensional explosion experiments examining the interaction between a blast wave and a sand hill

Sugiyama, Y., Izumo, M., Ando, H., and Matsuo, A.

Shock Waves （Shock Waves）  28 （ 3 ） 627 - 630 2018年05月

研究論文（学術雑誌）,  ISSN  09381287

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© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. Two-dimensional explosion experiments were conducted to discuss the interaction between a blast wave and sand and show the mitigation effect of the sand on the blast wave. The explosive used was a detonating cord 1.0 m in length, which was initiated in a sand hill shaped like a triangular prism and whose cross section was an isosceles triangle with base angles of 30∘. Sand-hill heights of 30 and 60 mm were used as parameters to discuss the effect of sand mass upon blast-wave strength. The interaction of the blast wave with the sand/air interface causes multiple peaks in the blast wave, which are induced by successive transmissions at the interface. The increase in the sand mass further mitigates the blast parameters of peak overpressure and positive impulse. The results of this experiment can be utilized to validate the numerical method of solving the problem of interaction between a compressible fluid and a particle layer.

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CFD-DEMを用いた衝撃波を伴う固気二相流の数値解析

木村 謙仁, 志村 啓, 松尾 亜紀子

混相流 32 （ 1 ） 65 - 72 2018年03月

研究論文（学術雑誌）, 共著, 査読有り

不足膨張条件下における外部ノズル推力予測の簡略化手法

御子柴 稜, 松尾 亜紀子, 富岡 定毅, 藤川 貴弘, 土屋 武司, 磯野 達志

日本航空宇宙学会論文集 66 （ 1 ） 15 - 23 2018年02月

研究論文（学術雑誌）, 共著, 査読有り

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Two-dimensional CFD–DEM simulation of vertical shock wave-induced dust lifting processes

Shimura, K., and Matsuo, A.

Shock Waves （Shock Waves）  28 （ 6 ） 1285 - 1297 2018年

研究論文（学術雑誌）,  ISSN  09381287

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© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. This paper conducts a numerical study of particle dispersion by vertical shock waves using a combination of computational fluid dynamics and the discrete element method (DEM). The Magnus force is important for particle dispersion, and the DEM approach can consider the rotation of individual particles and provide a detailed analysis of particle–particle and particle–wall interactions. Simulations are conducted and the results are compared with those of previous experiments, showing that the models can capture the particle dispersion process and shock wave geometry inside the mixed gas–particle region. During the particle dispersion process, the contact force due to the particle–particle interactions causes the particles to move upward after the shock wave passes and then decreases rapidly due to the low collision frequency in the particle cloud. The Magnus force is initially lower and has little effect until the contact force decreases, when it becomes dominant and maintains the particles’ upward movement. It is mainly driven by the gas rotation above the dust layer, and the effect of particle rotation is relatively small in comparison. The gas velocity gradient above the dust layer in the particle dispersion region is caused by gas–particle interactions. The particle dispersion region becomes wider and thinner over time, meaning that the gas velocity gradient above the dust layer becomes small and hence that the Magnus force (which is driven by the gas rotation) also becomes small. In contrast, the downward drag force remains constant during the vertical motion because it is primarily affected by the velocity difference between the particles and the gas. This means that the drag and Magnus forces eventually balance, and the particles stop rising.

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The effect of shape on the aerodynamic and thermal performance of hypersonic projectiles launched by a ground-based railgun

Kasahara H., Matsuo A.

AIAA Aerospace Sciences Meeting, 2018 （AIAA Aerospace Sciences Meeting, 2018）   （ 210059 ）  2018年

ISSN  9781624105241

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© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. In this paper, the effect of hypersonic-projectile design upon its aerodynamic coefficient is investigated to optimize projectile shape for ground-based-railgun launch. Previous studies on railgun-launch systems have suggested that projectiles experience significant thermal and aerodynamic effects when exiting the launcher because of their hypersonic exit velocity and the high enthalpy flow in the standard atmospheric condition. When designing a hypersonic projectile, the aerodynamic coefficient and thermal protection are crucial for maximizing range and withstanding heat. Two conditions of hypersonic flight, such as free flight and transitional ballistics, are simulated herein. To investigate the projectile’s geometric effect in the steady-flight condition, projectiles designed based on theory and empirical observation are compared. The aerodynamic result suggests that sharper projectiles do not always have smaller drag coefficients in simulation and theory because of a tradeoff between maximum pressure at the tip and pressure distribution on the latter half of the front shape. While temperature shows a similar trend compared to pressure, the maximum-temperature point is affected by projectile bluntness. Therefore, to optimize hypersonic design for thermal effect, it is inappropriate to adopt excess thermal protection at the tip, and an accurate prediction of maximum-heat-flux point is important. In addition to free-flight simulation, a transitional-ballistics simulation is performed. The interior and transitional calculations indicate that the precursor shockwave and sabot affect the flow field around the projectile. The sabot-separation phase can be divided into four stages based on the characteristics of the flow field. In the first and second stages, before the projectile undergoes the precursor shockwave, its shape has little effect on drag or velocity. However, when the projectile interacts with the sabot in the third and fourth stages, geometric effects can be observed. The theoretically optimized projectile is found to keep the highest flight velocity from transitional ballistics to free-flight.

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The effect of exit velocity and material on the sabot separation launched by ground-based railgun

Kasahara H., Matsuo A.

2018 Applied Aerodynamics Conference （2018 Applied Aerodynamics Conference）  2018年

ISSN  9781624105593

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© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. In this paper, the sabot separation process in super/hypersonic flight from 600 to 2501 m/s is numerically investigated by using CFD and RBD (Rigid Body Dynamics). Firstly, the motion of sabot separation is calculated for validating our in-house code. CFD-RBD code shows good agreements with Mehmet’s experiment. Secondary, the effects of exit velocity from muzzle are examined. While all sabot velocities differ, sabot separations indicate the same trajectory. The variation of sabot velocity can be eliminated by non-dimensionalization considering exit velocity. Finally, the effects of sabot material, which means mass density, are investigated with railgun acceleration condition. Sabot separation shows different motion completely depending on sabot material. However, non-dimensionalization eliminates the effect of sabot material on separation. Proposed non-dimensionalization method can represent the various sabot separation motions in unique one trajectory, considering exit velocity and sabot density in time term.

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Preliminary experiments on rotating detonation rocket engine for flight demonstration using sounding rocket

Goto K., Nishimura J., Higashi J., Taki H., Ukai T., Hayamizu Y., Kikuchi K., Yamada T., Watanabe S., Hotta K., Inakawa T., Kubota A., Yamaguchi M., Daicho T., Kawasaki A., Matsuoka K., Kasahara J., Matsuo A., Funaki I., Yasuda K., Mori K., Yagihashi H., Nakata D., Uchiumi M., Higashino K.

AIAA Aerospace Sciences Meeting, 2018 （AIAA Aerospace Sciences Meeting, 2018）   （ 210059 ）  2018年

ISSN  9781624105241

　概要を見る

© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Rotating detonation engine (RDE) is a promising candidate for future upper stage motor because of its high theoretical efficiency and short combustor length. Technological demonstration in space will be necessary to evaluate the performance and flight dynamics of RDE as a space propulsion system. Toward a flight test, we built an open-structure, rocket RDE-powered vehicle to measure thrust to validate a feasibility of an onboard propulsion system. We carried out 4.4 s combustion test, and achieved over 73% of ideal specific impulse above 1.1 MPa of static pressure in the RDE combustor.

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Numerical investigation of the gas-particle flow in the shock tube using discrete particle and continuum model

Kimura A., Matsuo A.

2018 Fluid Dynamics Conference （2018 Fluid Dynamics Conference）  2018年

ISSN  9781624105531

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© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. The numerical investigation of the gas-particle flow in the shock tube is conducted using the continuum model (Two-Fluid model) and the discrete particle model (CFD-DEM). From calculated results of both methods, particles are concentrated at downstream edge of particle bed and dispersed at upstream edge of particle bed with the passage of time. The incident shock wave is divided into the reflected shock and the transmitted shock because of interactions with particles. These flow field can be observed in the experiment conducted by Rogue et al., and Two-Fluid model and CFD-DEM can qualitatively reproduce the interaction phenomena between shock wave and particles. In the experiment, the pressure oscillations behind the reflected and the transmitted shock wave are observed as well as CFD-DEM, but no oscillation is seen in Two-Fluid model. Therefore, Two-Fluid model can qualitatively reproduce the interaction phenomena of shock wave and particles qualitatively, although the behavior of individual particle is neglected in the model.

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水中移動体の先端形状が飛しょう安定性に与える影響に関する数値解析

奥野航平, 松尾亜紀子

日本機械学会論文集 83 （ 856 ）  2017年12月

研究論文（学術雑誌）, 共著, 査読有り

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Validation of pulse-detonation operation in low-ambient-pressure environment

Matsuoka K., Takagi S., Kasahara J., Matsuo A., Funaki I.

Journal of Propulsion and Power （Journal of Propulsion and Power）  34 （ 1 ） 116 - 124 2017年06月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  07484658

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© Copyright 2017 by Nagoya University. A pulse-detonation thruster can generate a high-repeatability small impulse at a high operating frequency. To operate a pulse-detonation cycle in a vacuum environment without a purging material, a liquid-purge method proposed by Matsuoka et al. ("Development of a Liquid-Purge Method for High-Frequency Operation of Pulse Detonation Combustor," Combustion Science and Technology, Vol. 187, No. 5, 2015, pp. 747-764) and throat at the exit of the combustor were introduced. In the demonstration experiment, gaseous ethylene-liquid nitrous oxide, as detonable mixture, and a throat having an inner diameter of 3.6 mm (blockage ratio = 87%) were used. The measured cyclic flame-propagation speeds were 2005 ± 90 m/s and 92 ± 4% of the estimated Chapman-Jouguet detonation speed. Consequently, a 50 Hz pulse-detonation operation without a purging material in the ambientpressure range of 0.035-1.5 kPa was confirmed. A quasi-steady model, in which gases in the combustor are in the stationary state, was newly developed to investigate the operating characteristic of the pulse-detonation thruster. The experimental pressure history in the combustor during the burned-gas blowdown process was in good agreement with that of the model. Moreover, using the model, the thrust performance of the pulse-detonation thruster with a converging-diverging nozzle was investigated. It was found that the estimated specific impulse was comparable with that of the theoretical steady-state rocket engine.

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Supersonic Combustion Using Multiple Stinger-shaped Injectors

Kouchi, T., Tomioka, S., Hirano, K., Matsuo, A., and Masuya, G.

Transactions of JSASS 60 （ 1 ） 56 - 59 2017年01月

研究論文（学術雑誌）, 共著, 査読有り

Experimental Visualization of the Structure of Rotating Detonation Waves in a Disk-Shaped Combustor

Nakagami, S., Matsuoka, K., Kasahara, J., Kumazawa, Y., Fujii, J., Matsuo, A., and Funaki, I.

Journal of Propulsion and Power, Special Section on Pressure Gain Combustion 33 （ 1 ） 80 - 88 2017年01月

研究論文（学術雑誌）, 共著, 査読有り

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Development of High-Frequency Pulse Detonation Combustor Without Purging Material

Matsuoka, K., Muto, K., Kasahara, J., Watanabe, H., Matsuo, A., and Endo, T.

Journal of Propulsion and Power, Special Section on Pressure Gain Combustion 33 （ 1 ） 43 - 50 2017年01月

研究論文（学術雑誌）, 共著, 査読有り

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Investigation of Fluid Motion in Valveless Pulse Detonation Combustor with High-Frequency Operation

Matsuoka, K., Muto, K., Kasahara, J., Watanabe, H., Matsuo, A. and Endo, T.

Proceedings of the Combustion Institute 36 （ 2 ） 2641 - 2647 2017年

研究論文（学術雑誌）, 共著, 査読有り

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Numerical Investigation on Detonation Velocity in Rotating Detonation Engine Chamber

Fujii, J., Kumazawa, Y., Matsuo, A., Nakagami, S., Matsuoka, K., and Kasahara, K.

Proceedings of the Combustion Institute 36 （ 2 ） 2665 - 2672 2017年

研究論文（学術雑誌）, 共著, 査読有り

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Experimental Study of the Structure of Forward-Tilting Rotating Detonation Waves and Highly Maintained Combustion Chamber Pressure in a Disk-Shaped Combustor

Nakagami, S., Matsuoka, K., Kasahara, J., Matsuo, A., and Funaki, I.

Proceedings of the Combustion Institute 36 （ 2 ） 2673 - 2680 2017年

研究論文（学術雑誌）, 共著, 査読有り

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