Japan Aerospace Exploration Agency (JAXA) has been investigating scramjet engines inKakuda Space Center using Ram Jet Engine Test Facility (RJTF) et al. The engine tested at the flight condition of Mach 6 in RJTF showed very important characteristics depending on internal geometry. The authors found in the result of CFD research that a "hot triangle" is caused by 3-dimensional interaction of the cowl shock wave and the strut shock wave and that the hot triangle contributes to intensive combustion transition. Based on this hot triangle, an engine configuration with boat-tail strut is compared to that with 5/5-height strut which showed good thrust performance in the engine test. CFD is carried out to solve the inner air flow, and the two configurations are compared in the view point of the superiority of scramjet engine. It is found that fluid is transported from the top wall side to the cowl side automatically in the base flow behind the strut. Especially in the configuration with boat-tail strut produces a large circulation there. It suggests that the base flow behind the boat-tail strut can promote the uniformity of fuel distribution.

Japan Aerospace Exploration Agency (JAXA) has been investigating scramjet engines in KakudaSpace Center using RamJet Engine Test Facility (RJTF) et al. The engine tested at the flight condition of Mach 6 showed very steep fuel distribution. The authors are researching the influence of shock wave from strut-cowl system on the fuel distribution by using CFD based on RJTF tests, and have found advantages of strut in the engine. Here describe the authors the result of virtual experiments for optimization trial of fuel distribution in the engine by means of tracing back along streamlines in the view point where to set the fuel injection positions in order to let the fuel go into high mass flux area in the engine.Ⅰ．Introduction n hypersonic air-breathing engine researches many different trials have been done in order to obtain better propulsion performance or to create new systems. 1-4 In Japan since around 1985 National Aerospace Laboratory (present JAXA) has been carrying out scramjet engine research, and Ramjet Engine Test Facility (RJTF) was built in Kakuda Research Center (present Kakuda Space Center) in 1993 for the research.Kakuda Space Center has been conducting the scramjet engine tests for flight condition of Mach 4, 6, 8 and the higher in RJTF and another facility respectively. [5][6][7][8][9][10][11][12][13][14][15] In the scramjet engine tests carried out in the RJTF it has been found that the difference of engine inner configuration, mainly strut shape, produces large difference of thrust performance in the condition of Mach 6. 5 In addition to the above it has been also found that the fuel cannot spread all over the engine cross section and concentrates to the top wall side. 5 Some fraction of the fuel is exhausted without burning and does not contribute the thrust production. This prevents the engine from fully performing. Optimization for the fuel distribution is needed.In this viewpoint researches have been made on fuel injection for scramjet engines. Roughly classifying, they are a) how I 1 Senior Researcher,

No abstract

No abstract