SWT-120风洞稳定段的性能测量

Results of Survey of the Setting Chamber of SWT-120

在普通超音速风洞中,由于受到噪声干扰,很难进行有效的边界层转捩特性试验研究,针对超声速流动特点发展较低噪声风洞十分必要,而稳定段设计的好坏直接影响到下游试验段噪声水平。本文介绍一座低噪声风洞稳定段的结构和性能测量结果。先对稳定段的结构设计做了简单介绍,然后对实验结果进行分析,实验结果表明在大角度扩散段内装置孔锥,稳定段安装消音夹层和阻尼网组等部件后,气流的速度脉动和压力脉动明显降低,其中压力脉动降低一个量级,速度脉动为1%。进一步优化设计和改进工艺,速度脉动还可进一步降低。测量结果表明SWT-120稳定段的设计是成功的,对我们以后发展更高性能的静风洞有借鉴和参考价值。

It is very difficult to carry out boundary layer transition experiment effectively in general supersonic wind tunnel due to the influence of noise. So developing a low noise wind tunnel is very necessary for supersonic flow. And the noise downstream is affected directly by the design of setting chamber flow. This paper discusses the structural design and results of survey of a setting chamber of a low noise supersonic wind tunnel 120. First, the design of structure parameter of the setting chamber is introduced simply. Second, results of survey are discussed in detail. Results of experiment indicate that velocity fluctuation and pressure fluctuation can be reduced greatly by arranging a perforated cone in wide-angle diffuser, acoustic baffles and screens in setting chamber. Pressure fluctuation drops 90%, velocity fluctuation is about 1%, as the same as what achieved in NASA Langley. Results indicate that velocity fluctuation may drop more by optimizing design and improving techniques. The results of survey demonstrate the success of design of setting chamber for the supersonic wind tunnel-120. It is helpful for us to design the supersonic quiet wind tunnel in future.