防风网多孔动力效应的应用研究

Application Research on Porous Dynamical Effect of Windbreak

为了研究防风网的屏蔽功能,用理论分析的方法建立了防风网动力效应的数学模型.采用数值计算与风洞实验结合的方法研究了防风网前后的流场分布特点和网后风速的衰减规律.研究表明:在网后0~10倍网高的长度范围内,风流有40%~60%的衰减幅度.根据这个结果,以一大型露天煤粉堆场为实例,在煤堆场的上风向设置防风网,通过对堆垛表面摩擦风速的计算,得出该方案下堆垛煤尘的起尘率仅为37.40%,明显小于无网防护下煤尘73.6%的起尘率,表明设置防风网能有效降低煤尘表面的摩擦风速,减少煤尘的风蚀扬尘量.

The dynamical mathematic model of porous windbreak was established for investigation its shielding effect. The air velocity distribution characteristics around the windbreak and change law of air speed were obtained by the numerical calculation and wind tunnel experiment measurements. The results show that the air speed was reduced 40^--60~ through the holes along the lengthways direction of 0--10 times of windbreak height. According to the conclusion, as an example of the large scale open-air mine piles, the windbreak was constucted along the dominant wind direction and the friction velocities on surface of mine piles were statiscally analyzed. The wind-blown possibility of the mine dust was 37.40% under the protection of porous windbreak, far less than 73.60% for the case without any measure. That indicated the porous windbreak could decrease effectively the friction velocity of the mine powder surface and reduce the wind-blown mine powder quantity.