非对称来流下隔离段动态压力特性

Characteristics of wall pressure fluctuations in a straight isolator with asymmetric incoming flow

关键词:  超燃冲压发动机  隔离段  激波串  激波振荡  壁面压力脉动

Key words:  Scramjet  Isolator  Shock train  Shock oscillation  Wall pressure fluctuation

摘要:

为了探讨非对称来流下矩形隔离段内动态压力特性,用直联实验方式以及动态压力测量技术进行了试验,并用统计分析方法分析了数据。实验结果表明,入口来流的非对称性对上下壁面压力脉动大小以及传播平均速度有较大影响,而对频率无多大影响。激波串区域内壁面压力脉动向下游传播比向上游传播衰减得快。在隔离段出口超声速条件下,观测到的压力脉动频率主要在70 Hz以下,而在出口亚声速条件时,压力脉动的频率不仅有70Hz以下的部分,而且还有100~200 Hz之间的部分。

Abstract:

The characteristics of wall pressure fluctuations in a straight isolator with asymmetric supersonic flow were experimentally investigated by using wall pressure fluctuation measurements and statistically analysis.It was found that the upper wall pressure fluctuations are larger than the lower wall pressure fluctuations,but the frequency is the same.The mean propagation velocities in the upper wall are different from that in lower wall.The upstream propagating fluctuations decrease slightly with an increased distance,but the downstream propagation decreases rapidly with the distance.When the exit is supersonic,the frequency of wall pressure fluctuation is below 70Hz.While the exit is subsonic,wall pressure fluctuations contain components of both low frequency oscillations,which is less than 70Hz,and components of high frequency oscillations of 100Hz and 200Hz.