大扩张比喷管分离流动冷流试验研究

为研究流动分离条件下气流特性,针对某试验大扩张比喷管,开展了地面冷流试验研究。试验得到了分离点前后测点压强与入口压强的变化规律,并对测点压强数据进行了傅里叶分析。研究结果表明,随着入口压强升高,分离点前测点压强不断升高,分离点后测点压强降低,远离分离点的下游测点压强基本不变,且略低于环境压强;流动分离会导致分离点后压强脉动增大,且脉动主要为50Hz以内的低频脉动,该研究为大扩张比喷管的设计及试验提供了重要参考。

Experimental study on cold separation flow in large expansion ratio nozzle

In order to investigate flow characteristics of the separation flow, cold flow tests were conducted in a solid rocket motor nozzle with a high expansion ratio under the sea level condition. The influences of the inlet pressure on the pressure of test points upstream and downstream the separation location were revealed in the tests and pressure data were analyzed by means of FFT. The results show that the pressure increases for test points upstream the separation location but decreases for test points downstream the separation location. The pressure is steady and right below the ambient pressure for test points downstream and far away from the separation location. Pressure fluctuations become more evident after separation in comparison with that before separation, and the enhanced pressure fluctuations were mainly low-frequency fluctuations in the range of 50Hz. The research has important reference to the designing and testing of the nozzle with a high expansion ratio.