风障减少尘埃飞起的风洞模拟研究

Wind Tunnel Simulation of Dust Emission Prevented by Windbreaks

在环境风洞中对具有相同孔率但孔径不同的１１种风障模型（金属网）的流场特性及网后煤堆模型的起尘特性进行模拟实验。结果表明，风障（网）的屏蔽作用取决于网的孔率；孔径雷诺数Ｒｅ存在着临界值（该实验为１２００），当Ｒｅ小于临界值时，网后附近气流的湍流运动受到抑制，此时煤堆模型的起尘率随Ｒｅ的减小而减小，且对来流的湍流结构很敏感，当Ｒｅ大于临界值时，起尘率基本上不再随Ｒｅ变化而变化。

This paper describes a wind tunnel investigation of dust emission prevented by windbreaks. 11 windbreaks (wire screens) which are of the same porosity but different holes sizes were tested. The experimental results showed that the shelter effect of windbreaks, i.e. the reduction of mean wind speed behinds the windbreaks, is just dependent on the porosity, but the turbulence will be extinguished just behinds the windbreaks and the dust emission rate will be reduced if the hole size is too small. Therefore, when one modeling the process, the necessary (the main) similarity principles are: i) modeling of the turbulent flow of atmospheric boundary layer, ii) porosity of windbreaks, and iii) aperture Reynolds number Re * .