管道形状对超音速雾化降尘特性的影响

Influence of pipe shape on dust reduction characteristics of supersonic atomization

为治理煤矿行业中井下粉尘的污染问题,基于可压缩气流管内超音速流动理论,提出1种超音速雾化降尘技术;通过数值模拟的方法来研究不同结构、气动总压力对拉瓦尔喷管内超音速流动过程的影响,并通过激波、音速环以及轴向最大马赫数、轴线最大平均速度等现象来分析不同气动总压力下不同拉瓦尔喷管结构参数的超音速流动规律;搭建雾化特性实验平台,对最佳的喷管形状在不同的压力下进行降尘效率的计算,对比分析不同时刻和不同压力下降尘效率的变化规律。研究结果表明:凹形喷管在不同压力下的降尘稳定性最强,是制作雾化降尘喷头的最好选择。凹形喷管在不同压力下3种时刻的瞬时降尘效率都随着时间增加而逐渐升高,雾化降尘效果良好,当喷雾时间为3 min且气动压力为0.5 MPa时,凹形喷管的降尘效率为85.13%,降尘效率最高,降尘效果最好。研究结果可为治理煤矿井下采煤过程中的粉尘问题提供理论支持和治理手段。

In order to deal with the pollution problem of underground dust in the coal mining industry,a supersonic atomization dust reduction technology was proposed based on the theory of supersonic flow in compressible airflow pipes.By using the numerical simulation method,the influence of different structures and aerodynamic total pressures on the supersonic flow process inside the Laval nozzle was studied,and the supersonic flow law of different Laval nozzle structural parameters under different aerodynamic total pressures was analyzed through the phenomena such as shock waves,sonic rings,and the maximum Mach number in the axial direction,as well as the maximum average velocity along the axis.An experimental platform of atomization characteristics was established,then the dust reduction efficiency of the best nozzle shape under different pressures was calculated and compared,and the variation law of dust reduction efficiency at different times and different pressures was analyzed.The results show that the concave nozzle has the strongest dust reduction stability under different pressures,and it is the best choice for making the atomization dust reduction nozzles.The instantaneous dust reduction efficiency of the concave nozzle at three times under different pressures gradually increases with time,and the atomization dust reduction effect is good.When the spray time is 3 min and the pneumatic pressure is 0.5 MPa,the dust reduction efficiency of the concave nozzle is 85.13%.At this time,the concave nozzle has the highest dust reduction efficiency and the best dust reduction effect.The research results can provide theoretical support and control means for the dust problem in the process of underground coal mining.