The Influencf Of Non-Conventional Cavity On Supersonic Flow Process In Scramjet Combustor

In this paper, the research work is to improve the combustion efficiency of fuel in a scramjetcombustor and to enhance the mixing of fuel and supersonic air flow. The effects of six differentgeometric factors on supersonic flow field were discussed. The results can be referenced forfurther research.Experimental and numerical simulation investigations were carried out in this paper. Thetwo aspects are complementary to each other, and the respective advantages are adopted. Theresearch ofΛ-type, V-type, butterfly type and Shuttle type cavities shows that the four differentunusual cavities can improve the mixing efficiency and flame stability to some degree. In thispaperΛtype and butterfly type cavities are considered better in the enhancement of mixing,stability of flame and providence of a stable ignition. The research on openΛ-type cavities withdifferent included angles shows that the cavity with smaller included angle performs better in theflow field characteristics, but it brings more total pressure loss. Therefore, the cavity withincluded angle at 90°is considered the best in both the flow field characteristics and recovery oftotal pressure. The research on the openΛtype cavities with different ramp angles shows that thecavity with ramp angle at 45°is regarded as the best condition for its small total pressure lossand other advantages. The research on the depth of openΛ-type cavity shows that there exists abest cavity depth in every fixed length-to-depth condition. In this paper the height ratio offore-and-aft steps was firstly put forward to study the flow field characteristics, and the studyshows that with a small aft step height compression wave converts to expansion wave nearleading edge. Meanwhile the greater the ratio is, the stronger the expansion wave is. Hence thepressure of the whole combustor decreases and the intensity of shock reflection is weaker, whichleads to smaller resistance coefficient of the whole combustion chamber.With respect to pressure loss, the total pressure recovery coefficient of the scramjetcombustor increases with the increase of included angle. However, it firstly increases and thendecreases with the increase of ramp angle, and it decreases with the increase of cavity depth,decreases with the increase of the ratio of length to depth, and increases with the increase offore-and-aft steps height ratio.