Quasi-One-Dimensional Analysis of Scramjet Combustor

• 1、School of Traffic and Transportation Engineering, Hefei University of Technology, Hefei 230009
• 2、School of Mechanical and Engineering, Hefei University of Technology, Hefei 230009

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 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 alsonumerically 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 2.0P0, the back pressure increases as the inlet pressure increases and when the inlet pressure is not less than 1.5P0, 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.

Keywords： aerospace propulsion system scramjet combustor quasi-one-dimensional Euler equations finite-rate reaction