关键词: 准一维Euler方程;有限速率化学反应;一步反应;超燃冲压发动机;燃烧室

Abstract: Based on the quasi-one-dimensional Euler equations with finite-rate chemical reactions, a quasi-one-dimensional computational method for scramjet combustor performance analysis was developed by adding the source terms for the cross-sectional area variation, wall friction and fuel addition. One-dimensional numerical investigations of the hydrogen-fueled CARDC scramjet and NAL scramjet were simulated and compared with the common single-step reaction equilibrium model and our finite-rate reaction model. The characteristics of combustion flow field of the NAL scramjet under different hydrogen equivalence ratios and inlet pressures were also numerically simulated and analyzed. The results indicate that the accuracy and effectiveness of the two models are validated by good agreement between the predictions and experimental data. Furthermore, the finite-rate reaction model not only captures more details of the flow field, but also analyzes the effects of equivalent ratios, inlet pressures and other parameters. For the NAL scramjet, the pressure increases gradually as the equivalent ratio increases when the hydrogen equivalence ratio is not less than 0.6. The combustion induced back pressure begins to disturb into the isolator if the hydrogen equivalence ratio reaches 1.0, and the disturbing speed increases with the further increase of equivalence ratio. When the inlet pressure is not greater than 110.444kPa, the back pressure increases as the inlet pressure increases and when the inlet pressure is not less than 82.833kPa, the back pressure is isolated at the entrance of the straight section of combustor. An excessively small equivalent ratio and an excessively large inlet pressure can result in a serious decrease of the outlet Mach number, or even a subsonic outflow condition.