基于被动引射的大扩张比喷管流动数值研究

Numerical Study of Nozzle Flow with Large Expansion Ratio Based on Passive Injection

针对大扩张比喷管地面试验过程中分离流动现象,基于数值方法研究分离状态流场特征,分析了分离位置与喷管入口参数的关系,并与经验公式进行了对比。在此基础上,开展被动引射方案的仿真计算,分析引射筒长度、直径等参数对喷管流态的影响。计算结果表明,大扩张比喷管地面试验过程由于逆压梯度产生分离流动,数值计算流场及分离位置与经验公式结果接近;通过引射筒的被动引射可以实现地面试验时喷管满流状态,流场受引射筒长度和直径等参数影响。此研究结果可为大扩张比喷管地面试验设计提供参考。

In view of the separation flow phenomenon in the process of large expansion ratio nozzle ground test, the flow field characteristics of separation state are studied based on numerical method, and the relationship between separation position and nozzle flow parameters is analyzed, and compared with empirical formula. On this basis, the simulation calculation of the passive injection scheme is carried out, and the influence of parameters such as ejector barrel length and diameter on nozzle flow pattern is analyzed. The results show that the flow field and separation position of the nozzle with large expansion ratio are close to the results of the empirical formula due to the adverse pressure gradient during the ground test;the full flow state of the nozzle can be realized by passive injection of the ejector barrel, and the flow field is affected by the length and diameter of the ejector barrel. The results of this paper can provide a reference for the ground test design of nozzle with large expansion ratio.