超声速喷流啸声的控制方法

Control methods for supersonic jet screech tones

关键词:  喷流噪声  啸声  控制  推力损失

Key words:  Supersonic jet  Screech tone  Control  Thrust loss

摘要:

通过实验比较了几种超声速喷流啸声的控制方法,包括附加三角凸台和开V形槽的收敛喷嘴。实验结果表明,带三角凸台和V槽的喷嘴对啸声幅值有明显的抑制,尤其是凸台喷嘴对啸声的模态也产生了明显的影响,但是啸声成分仍然存在,并且在上游方向依然占主导地位。在此基础上提出了一种新的控制方法——凸台加V槽的组合喷嘴,实验结果表明,组合喷嘴完全抑制了啸声,而且对于其它超音速喷流噪声成分的幅值也有一定程度的降低。最后还对各种结构喷嘴的气动推力损失进行了综合评估,结果表明组合喷嘴的推力损失介于V槽喷嘴和三角凸台喷嘴之间,平均推力损失在3%左右。

Abstract:

Several methods on controlling supersonic jet screech tones are experimentally compard.The tested nozzle configuration consists of Delta-Tabs and chevrons.The experimental results show that the nozzles,with Delta-Tabs or Chevrons,distinctly decrease the amplitude of screech tones.The Delta-Tab nozzle also influences the modes of screech tones.However,screech tones still exist and dominate in the upstream direction.Based upon the experimental investigation,the compound nozzle,Delta-Tab plus chevron,is proposed.It is demonstrated that the compound nozzle totally eliminates screech tones.Furthermore,the compound nozzle can also reduce,to some extent,the intensities of other components of supersonic jet noise.In addition,thrust losses of nozzles in the paper have been evaluated.The results show that the thrust loss of compound is about 3% between the chevron and Delta-Tabs.