警用脉冲防暴水炮管外动力过程数值模拟

为研究脉冲防暴水炮发射后在管外的动力过程,在Open FOAM软件上利用LES和VOF相耦合的方法对脉冲防暴水炮气液两相流流动过程作数值模拟。对水炮发射过程及其在距端口1.5m范围内的压力分布和速度分布做了分析。用SAMPLE软件对流场数据进行了采样,得到了用其它手段难以获得的数据。模拟表明,液柱形状急剧变化,首先形成蘑菇形,接着被压缩成半球形,在球形内部压力的作用下,半球形液弹被压缩成弧形。压力的作用距离集中在距端口300mm范围内,并很快降到了0.4MPa以下,其间因为压力有一个二次突然释放的过程,造成了二次喷射现象。速度是一个急剧先增加后减小的过程。所采用的圆柱式喷嘴使压力和速度下降太快,不利于提高水炮射程,需要改用其它类型的喷嘴。

Numerical Simulation of External Dynamic Process of Launch Tube of Pulsed Anti-riot Water-cannon

In order to study the external dynamic process of launch tube of Pulsed Anti-riot Water-cannon（PAW）,numerical simulation based on Open FOAM is applied by using the method of Large Eddy Simulation（LES） coupled with Volume of Fraction（VOF）.Launch process,pressure distribution,velocity distribution within 1.5m from the outlet of the cylindrical nozzle are investigated.Data of flow field which not easy to get in other methods are acquired by using SAMPLE software.Simulation result shows that the profile of water pillar likes a mushroom at the beginning of launch,and then likes a hemisphere,then turns to a camber finally in the influence of high pressure gas in the core of hemisphere.The effective distance of pressure is no more than 300mm,and quickly decreases to 0.4MPa,second ejection phenomenon also appear within this distance because of the second suddenly emission.Velocity increases sharply and decreases rapidly.The cylindrical nozzle is not conductive to the increase of range because of the large decrease of pressure and velocity.Other kinds of nozzle seem to be a good choice.