引射火箭启动过程的进气道动态特性仿真研究

Numerical Study on the Dynamic Characteristics of the Inlet During ERJ Start-up

引射火箭冲压(ERJ)被认为是有效解决多通道涡轮基组合动力中涡轮机与冲压发动机推力不连续问题的重要技术途径之一。本文采用三维瞬态数值模拟的方法对ERJ全流道结构进行计算分析,旨在研究涡轮/火箭/冲压多通道组合动力ERJ通道火箭启动过程对组合进气道的影响及ERJ通道的性能特点。研究表明,火箭低工况启动后ERJ通道高压区随火箭射流向下游喷管区域传播,在喷管区受限反向前传导致进气道结尾激波前移,直至达到压力平衡状态后维持在某一区域内驻定。结尾激波前移直到正激波完全推出组合进气道ERJ通道,该通道空气流量降低20.72%,ERJ通道的推力较结尾激波未推出时的平均推力降低近16%,合理设置火箭启动及变工况方案有利于涡轮/火箭冲压组合动力推力接续的平稳过渡。

The problem of insufficient thrust for high Mach number operation of turbine and poor performance of low Mach number operation of ramjet can be effectively solved by Ejector Ramjet(ERJ)low Mach number relay turbine operating output thrust in multi-channel combined power.In this paper,a three-dimensional transient numerical simulation is used to analyse the ERJ full flow channel structure,aiming to study the influence of the rocket start-up process of the ERJ channel on the multi-duct combined cycle inlet and the performance characteristics of the ERJ channel during the modal transition from the turbine channel to the ERJ channel in combined turbine/rocket/ramjet multi-channel power.The following conclusions are obtained from the study:The high pressure region of the ERJ channel propagates with the rocket jet to the downstream nozzle region after the rocket starts at low operating condition,restricted and backward propagation in the nozzle region leads to the forward movement of the inlet terminal shock until it reaches the pressure equilibrium state and then stays in a certain region.The air flow in this channel is reduced by 20.72%,and the average thrust of ERJ channel is reduced by nearly 16%compared with the average thrust when the terminal shock stays in ERJ channel.Appropriate setting of rocket start-up and variable operating conditions are conducive to smooth transition of combined turbine/ERJ power thrust succession.