造雪机用旋流喷嘴雾化特性的模拟研究

Numerical study on atomization characteristics of swirl nozzle for artificial snowmakers

旋流喷嘴作为造雪机关键部件,其雾化效果直接影响成雪效果。为进一步探索旋流喷嘴雾化特性,基于VOF to DPM模型,建立旋流喷嘴雾化的数值模型,对旋流喷嘴进行三维数值模拟。研究不同入口压力对液滴粒径、液滴速度等雾化特性的影响,并通过实验验证了模型的准确性。结果表明,喷雾充分发展后,索特平均粒径随入口压力的增大而减小,入口压力增大,增强了液体和空气之间的气动不稳定性,促进了液体的破碎分解,缩短了液体所需破碎时间;液膜和液滴速度都随着入口压力的增大而增大,当入口压力由0.6 MPa增大到1.4 MPa时,出口液膜和液滴速度分别增加58.8%和52.2%;在破碎过程中,动能转化为表面能,会使液体速度发生削减。

Swirl nozzle is regarded as the key component of on artificial snowmaker, its atomization effect directly affects the snow quality. A three-dimensional numerical model of swirl nozzle atomization is established based on VOF to DPM model, in order to further explore the atomization characteristics of swirl nozzle. The effects of inlet pressure on the atomization characteristics such as droplet size and velocity are studied, and the accuracy of the model is verified by experiments. The results show that after full development of spray, the Sauter mean diameter decreases with the increase of inlet pressure. The rising pressure enhances the aerodynamic instability between liquid and air, promotes the liquid breakup, and shortens the breakup time of liquid. The velocity of liquid film and droplet both increase with the rising inlet pressure. With the inlet pressure increasing from 0.6 MPa to 1.4 MPa, the velocity of liquid film and droplets can increase by 58.8% and 52.2%. Moreover, during the breakup process, the conversion of kinetic energy into surface energy reduces the liquid velocity.