两级超声速引射器流动机理研究

Supersonic to Supersonic Ejection Mechanism of a Two-Stage Ejector

关键词:  两级引射器  超-超引射  流动机理  压力匹配 

Key words:  Two-stage ejector  Supersonic-supersonic ejection  Flow mechanism  Pressure matching

摘要:

超声速引射器在航天发动机、化学激光器等的地面试验所需压力恢复系统中有着重要的应用,采用超-超引射方式是优化压力恢复系统的性能和实现设备小型化的途径之一。为探索适用于超-超引射器的设计准则,对一种两级超声速引射器的超-超引射流动现象开展了研究,试验发现该构型引射器在特定压力匹配范围内即可实现一、二级主流间的超-超引射又可以实现主流对二次流的超-超引射,结合数值仿真对流场结构和参数的分析表明超-超引射的形成机制可归结为压力匹配问题,通过提高来流总压与混合室匹配静压的压比可建立超-超引射；混合室匹配静压由引射气流主导；提高二次流总压或降低主流压力均可提高二次流马赫数,该规律对建立超-超引射、提高引射效率有指导意义。 

Abstract:

Supersonic ejector has important applications in the pressure recovery system for ground test of aerospace engines and chemical lasers. Using Supersonic-Supersonic ejection is one of the approaches to optimize performance of the pressure recovery system and achieve device miniaturization. To explore Supersonic-Supersonic ejector design criteria, this paper studied the phenomena of Supersonic-Supersonic ejection on a two-stage ejector. In the test, it is found that the Supersonic-Supersonic ejection can both be realized between the main flows or between the main flow and the secondary flow at a designated pressure range. Combined with simulation results of the flow field structure and parameters, the mechanism of Supersonic-Supersonic ejection was proved to be the pressure matching matter. The Super-Super ejection mode can be established by increasing the ratio between the total pressure of the flow and the matching static pressure in the mixing chamber. The matching static pressure is led by the main flow while increasing the pressure of the secondary flow or reducing the pressure of the main flow can both increase the Mach number of the secondary flow. It has guiding significance for establishing Supersonic-Supersonic ejection mode and furthermore improving the ejection efficiency. 