两种前体压缩方式对斜爆震燃烧影响的数值研究

Numerical Study on Effects of Two Forebody Compression Methods on Oblique Detonation Combustion

关键词:  等强激波压缩  等熵压缩  斜爆震  总压损失  数值模拟

Key words:  Equal strength shock compression  Isentropic compression  Oblique detonation  Total pressure loss  Numerical simulation

摘要:

为推动工程应用，探究斜爆震发动机前体压缩程度对斜爆震燃烧的影响，建立了两道等强激波和斜激波-等熵两种前体压缩简化模型，通过数值模拟对比了飞行马赫数8~10条件下，两种压缩方式对斜爆震波结构以及斜爆震波总压损失的影响。结果表明，前体压缩方式的差异会引起斜爆震波起爆区结构以及起爆位置的变化，且随着飞行马赫数降低，压缩方式对起爆区结构影响减小，对起爆位置影响增大。两道等强激波的前体压缩方式对应的斜爆震燃烧过程总压损失更小，同时可缩短点火起爆距离，有利于缩短燃烧室长度。但综合考虑进气压缩与燃烧过程，斜激波-等熵的前体压缩方式对应燃烧室出口气流总压更大。斜爆震发动机的设计需要综合考虑前体压缩与斜爆震燃烧损失以实现发动机总体性能最优。

Abstract:

In order to promote engineering applications and investigate the effects of ODE forebody compression degree on the combustion characteristics of oblique detonation wave （ODW）， two simplified compression models， namely two equal strength shock compression and oblique shock-isentropic compression were established. Numerical simulations were conducted to study the effects of two compression methods on the ODW structure and the total pressure loss of ODW under flight Mach numbers ranging from 8 to 10. Results show that the difference of forebody compression methods may change the initiation structure and the initiation position of ODW inside the combustor. As the flight Mach number decreases， the impact of compression methods on the initiation structure undermines， but the effect on the initiation position strengthens. Two equal strength shock compression has lower total pressure loss of ODW combustion process， and can reduce the ignition distance， which helps shorten the combustor length. However， considering the process of inflow compression and combustion together， oblique shock-isentropic compression has larger total pressure at the outlet of combustor. The design of ODE needs to comprehensively consider the forebody compression and ODW combustion loss to achieve the best overall engine performance.