内并联式TBCC进气道模态转换过程流动特性分析

Analysis of Over/Under TBCC Inlet Mode Transition Flow Characteristic

针对组合动力(TBCC)进气道模态转换过程中出现的非定常气动现象,采用稳态/非稳态数值模拟方法对相关流动特性及其影响因素与流动机理开展了研究。结果表明:由涡轮发动机工作状态向冲压发动机工作模态转换过程中,进气道内出现结尾激波沿流向前后振荡现象,振荡频率约为130 Hz;当冲压流道反压引起的激波未前传至模态转换分流板前时,冲压发动机工作状态对结尾激波振荡不产生影响。在相同的发动机工作状态下,随着模态转换速度的增加,结尾激波振荡频率逐渐增大。文中研究的进气道内结尾激波振荡现象可通过亚声速管道内波的传播理论进行解释和分析。

Unsteady flow characteristic exits during the turbine based combined cycle （TBCC） inlet mode transition. Thus, steady and unsteady numerical simulation methods are used to investigate the this flow fields in the present paper. The numerical results indicate the terminal shock oscillates in the TBCC inlet during the mode transition from turbojet mode to ramjet mode. And the terminal shock oscillation frequency is about 130 Hz. At the same time, the shock oscillation frequency is not affected by ramjet engine operation modes until the shock in ramjet flowpath is expelled to the front of the splitter. At the same operation condition of the engine, the frequency of shock oscillation increases as the rate of inlet mode transition is raised. The terminal shock oscillation phenomena occurred during TBCC inlet mode transition can be explained by subsonic wave propagation theory.