西北工业大学直流式低湍流度风洞设计中的几个关键问题

Some Key Problems in the Design of the NPU Open-Circuit Low- Turbulence Wind Tunnel

本文主要阐述西北工业大学直流式低湍流度风洞设计中的几个关键问题,如大收缩比、多层网、低噪声风扇以及抑制风扇噪声上传的一些措施.这座风洞的最低湍流度为0.01％～0.02％.这一湍流度已达到了国际上回流式低湍流度风洞的最高水平.通常直流式风洞由于进气及环境噪声的影响较回流式风洞为大,且风扇噪声的影响亦较大,故其湍流度常较回流式风洞大.西北工业大学的直流式低湍流度风洞由于在设计中对于降湍、减噪作了综合处理,故其湍流度达到了回流式风洞的最高水平.本文主要阐述西工大低湍流度风洞设计中的几个关键问题.

Some key problems in the design of the NPU (Northwestern Polytechnical University) open-circuit low-turbulence wind tunnel are described in this paper. The minimum turbulence level of this wind tunnel is less than 0.02% in the centre regin of the test section for the speed range V=15-50 m / s. In addition to the well known measures used in low-turbulence wind tunnel design such as large contracton ratio and multi-screens, the authors pay special attention to the reduction of the effect of noise in the tunnel design. These key measures used in the NUP low-turbulence wind tunnel design are: low noise fan design, flow diversion annular channel used at the outside of the fan, and a noise reduction section added forward of the fan section to prevent the upstream propagation of the fan noise. Thus, the turbulence level of the NPU low-turbulence wind tunnel is lower than the best level of open-circuit low-turbulence wind tunnels in the world that the authors know of and is almost the same as the best level of the closed circuit low-turbulence wind tunnels in the world.