诱导气流对转载点雾化特性影响规律的数值模拟与试验

Numerical and experimental study on spray characteristics with effect of induced airflow on transshipment point

为了分析煤矿转载点诱导气流对喷雾降尘过程中雾化粒度的影响,采用计算流体力学(computational fluid dynamics,CFD)离散相模型的粒子跟踪技术,模拟了不同诱导气流条件下雾滴粒径的分布特性。分析结果表明:在诱导气流的影响下,雾滴颗粒向导料槽出口漂移明显,粒径统计项D[3,2]和D[4,3]随诱导气流风速的增加而减小,减幅分别为17.17%和16.19%;同时,雾化压力的增大,提高了雾滴颗粒发生二次破碎的强度,导致雾化粒度随压力的增大而减小。根据结论,对转载点高压喷雾降尘系统进行了改进,现场喷雾压力由1.5 MPa提高到6.2 MPa,调整雾化场轴向横截面与诱导气流方向之间呈30°夹角,现场实践表明:相对于改进前,转载点全尘浓度和呼吸性粉尘浓度分别降低了88.60%和78.96%。

In order to study the spray characteristics affected by induced airflow on the transshipment point,the discrete phase particle tracking technology based on the CFD theory was used to investigate the distribution characteristics of droplets in different induced airflow conditions.The results show that with the influence of induced airflow,the phenomenon of droplets drifting to guide chute exit is obvious.The two widely used statistics items D[3,2]and D[4,3]decrease with the increase of velocity of induced airflow,and the average decreases are 17.17% and 16.19% respectively.At the same time,with the increase of atomization pressure,the strength of secondary breaking is enhanced,which leads to the decrease of the atomized particle size.According to the above conclusions,the high-pressure spray system on the transshipment point can be improved.The spray pressure was increased from 1.5 MPa to 6.2 MPa,and the angle between the axial cross section of atomization field and induced airflow was adjusted to the degree of 30°.The experiment results show that the total dust concentration and respirable dust concentration are reduced by 88.60% and78.96% respectively on the transshipment point after the improvement of the spray system.