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通过求解Navier-Stokes方程对三维矩形截面直连式煤油碳氢燃料超燃燃烧室进行了数值模拟,分析了当量比不同时对超燃燃烧室燃烧性能的影响。结果表明,在燃烧室入口马赫数为2、静温为589.3K、静压为88877.2Pa、煤油总当量比为1.0的条件下,当量比对超燃燃烧室燃烧性能的影响可分为三类:第一注油位当量比Φ为0.3时,没有稳定燃烧,最终熄火;第一注油位当量比Φ为0.4~0.6时,燃烧室燃烧效率基本不变;第一注油位当量比Φ为0.7~1.0时,燃烧效率逐渐升高;第一注油位当量比Φ为0.4~0.6时,壁面压力曲线基本重合;第一油位当量比Φ在0.7~1.0的变化过程中,压力曲线凸起位置也在前移,随着当量比的增加,反压越来越大,燃烧扰动已经影响至隔离段内。在总当量比不变的条件下,适当加长燃烧室长度可提高燃烧效率。当量比对超燃冲压发动机燃烧模态有较大影响,随着第一注油位当量比的逐渐增加,燃烧呈现由超燃模态过渡到亚燃模态的特征。
The Navier-Stokes equations were used to simulate the three-dimensional straight-section kerosene-fuel combustor with rectangular cross-section. The effect of different equivalence ratios on the combustion performance of the combustor was analyzed. The results show that the effect of equivalence ratio on the combustion performance of a combustible combustion chamber can be divided into three categories under the condition of 2 Mach inlet, 589.3K static temperature, 88877.2Pa static pressure and total equivalent ratio of kerosene of 1.0. : The first injection level equivalence ratio Φ of 0.3, there is no stable combustion, the final flameout; the first injection equivalent ratio Φ is 0.4 ~ 0.6, the combustion chamber combustion efficiency is basically unchanged; the first injection equivalent ratio Φ is 0.7 ~ 1.0, the combustion efficiency gradually increased; when the first injection equivalent ratio Φ is 0.4 ~ 0.6, the wall pressure curve basically coincides; the first oil equivalent ratio Φ in the 0.7 ~ 1.0 change process, the pressure curve raised position In the forward move, as the equivalent ratio increases, the backpressure increases and the combustion disturbance has already affected the isolation section. In the same total equivalence ratio conditions, the appropriate lengthened combustion chamber length can improve combustion efficiency. The equivalence ratio has a great influence on the combustion mode of the scramjet. With the gradual increase of the equivalence ratio of the first injection level, the combustion shows the transition from the scram mode to the sub-combustion mode.