连续式跨声速风洞试验段降噪技术

利用中国空气动力研究与发展中心（CARDC） 0.6 m连续式跨声速风洞试验平台，分析了试验段噪声源产生及回路传播的机理，对压缩机尾罩和第四拐角段进行声学处理以降低来流噪声，并采用风洞二喉道节流状态运行抑制试验段下游噪声的前传，有效屏蔽了回路噪声对试验段的影响。据此开展了试验段不同通气壁型式、不同设计参数的主动降噪方案优化设计及其对比试验研究，获取了较优的试验段壁板设计方案，最终实现了风洞试验段气流压力脉动系数低于0.8%的噪声设计指标要求。 

Noise reduction technology in test section of continuous transonic wind tunnel

According to the acoustic experimental conducted in the 0. 6m continuous transonic wind tunnel of CARDC(China Aerodynamics Research and DevelopmentCenter), the noise generation process in test section and the propagation process in tunnel circuit were researched. Acoustic treatments were performed on both the compressor rear cone and the fourth corner to prevent the emitted noise from propagating forward. Meanwhile the wind tunnel was running with second throat throttling to suppress the downstream noise. With those effective means to reduce the circuit noise, the optimization design of active noise reduction schemes with different ventilation wall types and different design parameters was carried out, then an excellent design for the test section wall was achieved. The wind tunnel pressure fluctuation coefficient reached the target of less than 0. 8%,the advanced international level.