Experimental Research on Noise Reduction for Continuous Transonic Wind Tunnel Loop

连续式跨声速风洞回路吸声降噪技术试验研究

¹ State Key Laboratory of Aerodynamics, China Aerodynamics Research and Development Center, Mianyang 621000, China
² Facility Design and Instrument Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China

Received: 19 September 2019

Abstract

The noise level of wind tunnel test section is respected as one of the most important performance specifications to represent the flow field quality, especially for large scale wind tunnel. According to the acoustic experimental research conducted in the 0.6 m continuous transonic wind tunnel of CARDC, main noise sources in the tunnel loop included the compressor, the high-speed diffuser and the test section. To reduce the noise in the test section, it is necessary to prevent the test section from the compressor noise propagated both forward and backward. In 0.6 m wind tunnel loop, acoustic treatments were installed on both the compressor rear cone and the fourth corner to prevent the noise emitted from the compressor from propagating forward. The vanes in the forth corner were filled with glass fibers and covered with perforated panels. And the compressor rear cone was covered with three layers of micro-perforated panels. With acoustic treatment in the tunnel loop and the second throat throttling, the fluctuation pressure coefficient (ΔC_p) is lower than 0.8%, which is close to the international advanced level.

摘要

风洞试验段噪声（气流压力脉动）是评价风洞流场的重要指标之一，对高品质流场要求的大型风洞设计提出了严峻挑战。通过中国空气动力研究与发展中心（CARDC）0.6 m连续式跨声速风洞沿程回路噪声测试，分析得到风洞主要噪声源为：风洞压缩机、高速扩散段（含二喉道段）、试验段本身（含模型支架段）。其中，来自试验段上游的压缩机噪声必须通过沿程回路吸声降噪措施进行隔离。提出了压缩机尾罩段洞壁和整流罩尾椎采用微穿孔板，风洞第四拐角段导流片填充复合吸声材料2种降噪方案，均取得了良好的降噪效果。最终通过试验段自身通气壁壁板参数优化等主动降噪方案，并采用风洞二喉道节流状态抑制试验段下游噪声前传的措施，实现风洞试验段压力脉动系数ΔC_p≤0.8%的噪声设计指标要求。