基于CFD技术的脉冲防暴水炮高压气嘴的结构设计

Configuration optimization of pulsed anti-riots water cannon gas nozzle based on CFD technology

射流出口速度值是影响脉冲防暴水炮技术性能的敏感因素,为研究不同结构气嘴对射流出口速度的影响,采用CFD技术数值研究了三种不同入口面积气嘴的二维流场,其中大涡模拟方法和二维非稳态的VOF模型被用于描述气嘴流场的湍流分布和追踪管内外的气液界面,研究发现过大或过小的气嘴入口面积都会减慢水炮的发射过程,不同的气嘴结构对于初始时刻的射流形状是没有影响的,但因改变了管内的气液参混过程,从而导致对射流的一次和二次雾化产生不同影响。

Water jet nozzle velocity is such a sensitive factor that may influence the technical performance of pulsed anti-riots water cannon.In order to study the influence of different gas-nozzle structure to water jet nozzle velocity,2-D flow field with three different gas-nozzles with different inlet area is studied by adopting CFD technical value,in which large Eddy Simulation and VOF model were used to describe the turbulent flow distribution and track the gas-liquid interface both inside and outside of the pipe.The results show that bigger or smaller the gas-nozzle entrance acreage is,the launch process may become slower,while the gas-nozzle with different structure may not influence the gas-liquid distribution at first,but may cause different influence on first and second water jet atomization since gas-liquid mix process inside the pipe is changed.