Research On Optimization of Two-Dimensional Supersonic Jet Noise Reduction.

二维超音速射流降噪优化研究。

基本信息

批准号：
05555259
负责人：
KAJI Shojiro
金额：
$ 6.59万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

项目摘要

For the purpose of reducing supersonic jet noise, application of porous plug nozzle as well as ejector nozzle was investigated. In the case where an airfoil shaped porous plug was inserted into two dimensional rectangular nozzle, its effect on screech and shock associate noise was studied. When the porous plug was placed a little far downstream from the jet nozzle, sound of the edge-tone type mechanism appeared. When the leading edge of the porous plug approached the jet nozzle exit, edge tone disappeared but screech appeared. Further, when the leading edge of the porous plug was inserted into the jet nozzle, screech also vanished. Such tendency was considered to be ascribable to the highly turbulent flow around the porous plug though holes which was observed by flow visualization.The method to reduce noise by rapidly reducing the velocity of high speed jet by use of mixer-ejector nozzle was studied. Measurement of fluctuating pressures on ejector wall showed that in the upstream part of the mixer-ejector nozzle the lower frequency component was dominant while the higher frequency component became dominant in the downstream part, and further, the level of both components increased as we went downstream.The flow field showing the mixing process in the mixer-ejector nozzle was simulated by the computational fluid dynamics. It was revealed that in the mixing process of core and secondary flows, the supersonic core flow repeats compression and expansion several times, then the rolling up of a large scale streamwise vortex starts which is strengthened as the flow proceeds downstream.

为了减少超音速喷射噪声，研究了多孔塞喷嘴以及喷射器喷嘴的应用。如果将机翼形状的多孔插头插入到二维矩形喷嘴中，则研究了其对尖叫和冲击膜噪声的影响。当将多孔插头放在距离喷嘴的下游时，会出现边缘音型机构的声音。当多孔插头的前缘接近喷嘴喷嘴出口时，边缘音调消失了，但出现了尖叫声。此外，当将多孔插头的前缘插入喷嘴中时，Screech也消失了。这种趋势被认为可以归因于多孔塞周围的高度湍流，但通过流动可视化观察到，通过使用混合器启示器喷嘴来迅速降低高速射流的速度来减少噪声的方法。测量弹出器壁上波动压力的测量表明，在混合器启动器喷嘴的上游部分中，较低的频率成分是主导的，而较高的频率成分在下游部分中占主导地位，此外，随着我们下游的流动磁场，这两种组件的水平都增加了。显示了混合器 - 放射器喷射的混合过程，该流程被模仿了计算的动态，该计算机的动态化了动力学的动态。据透露，在核心和次级流的混合过程中，超音速核流量重复压缩和膨胀几次，然后大规模流涡流的滚动开始，随着流量下游的流动，它会增强。