化学平衡效应对冲压燃烧室性能潜力与工作过程关系的影响分析

Effects of Chemical Equilibrium on Relation Between Performance and Process for Scramjet Combustor

为了研究化学平衡效应对冲压发动机燃烧室性能潜力以及工作过程关系的影响,分析了考虑和不考虑化学平衡效应的准一维分析方法获得的三种典型冲压燃烧室工作过程与性能潜力的差别。研究结果表明,化学平衡效应减小了燃料的燃烧效率、燃烧室所需扩张比以及比冲,改变了高飞行马赫数下燃烧室扩张比与性能的对应关系;不考虑化学平衡效应时,亚声速燃烧室的最大比冲略优于双模态燃烧室,亚声速燃烧室和双模态燃烧室的最大比冲都出现在特征马赫数最小时;当考虑化学平衡效应时,双模态燃烧室的最大比冲略优于亚声速燃烧室,亚声速燃烧室的最大比冲出现在特征马赫数1时,双模态燃烧室的最大比冲在飞行马赫数4,5,6,7时分别出现在特征马赫数0.3,0.4,0.7和1.5附近;在高飞行马赫数时,应研究确切的化学反应过程,以确切协调燃烧室设计关系。

To study the effects of chemical equilibrium on the relation between performance and process of ramjet,the difference of process and performance in three typical ramjet combustors with a quasi one-di- mensional method was stndied, while the chemical equilibrium effect was taken or not taken into account. The results indicate that chemical equilibrium diminishes the combustion efficiency, combustor divergent ra- tio required and performance, and especially the relation between divergent ratio and performance in high flight Mach number is changed. When chemical equilibrium effect is not taken into account, the highest specific impulse of subsonic combustor is higher than that of dual-mode combustor, and the highest specific impulse of both combustors are achieved when characteristic Mach number tends to be minimal. While chemical equilibrium effect is taken into account, performance of dual-mode combustor is higher than that of subsonic combustor. The highest performance of subsonic combustor is achieved at characteristic Mach num-ber of 1, while the highest performance of dual-mode combustor is achieved near the characteristic Mach number of O. 3, O. 4, O. 7 and 1.5, respectively, when flight Mach number is 4, 5, 6 and 7. It is sugges- ted that the precise chemical process in the combustor should be studied to confirm the combustor design at high flight Mach number.