著者

小寺 正敏 須浪 徹治 伊藤 勝宏 Kodera Masatoshi Sunami Tetsuji Ito Katsuhiro

出版者

宇宙航空研究開発機構

雑誌

宇宙航空研究開発機構特別資料: 航空宇宙数値シミュレーション技術シンポジウム2005論文集 = JAXA Special Publication: Proceedings of Aerospace Numerical Simulation Symposium 2005 (ISSN:1349113X)

巻号頁・発行日

vol.JAXA-SP-05-017, pp.221-226, 2006-02-28

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In this study, CFD has been applied to the prediction of the characteristics of two scramjet engines that will be tested at Mach 8 in JAXA's flight program for 2005. The engines each has the Hyper Mixer (HM) injector, which generates streamwise vortices to enhance supersonic mixing and combustion, or the Back Step injector (BS), which generates no streamwise vortices. CFD results showed good agreements with data obtained from preflight experiments in the High Enthalpy Shock Tunnel. Comparisons between the CFD results for the two engines showed that the mixing ability of the engine with HM (HM engine) was much better than that of the engine with BS (BS engine), because streamwise vortices promoted the spread of H2 distribution over the combustor flow path for HM engine, though the H2 distribution concentrated near the combustor bottom wall for BS engine. Therefore combustion occurred widely in the supersonic core flow for HM engine, while ignition occurred near the injector within the bottom wall boundary layer and combustion occurred locally along the edge of the H2 distribution for BS engine. The total pressure and heat losses were larger for HM engine than those for BS engine despite the larger amount of heat release. Thus the Thrust Potential (Tp) was superior for HM engine to that for BS engine, though Tp for HM engine decreased and approached to that for BS engine as going downstream of the combustor due to the losses dominating over the increment of heat release. This tendency was more remarkable when the nozzle with a fixed expansion ratio was applied to the engines. The changes of the free stream and wall temperatures proved to be sensitive for only the ignition point for HM engine. The change of the fuel equivalence ratio largely affected the ignition point and the heat release distribution for HM engine, while only the heat release distribution in the downstream of combustor for BS engine.