压力旋流喷嘴内流场特性模拟研究

Numerical investigation on inner flow field of pressure swirl nozzle

针对通过试验研究压力旋流喷嘴获取其雾化特性成本较高、耗时长、理论计算难以实现的问题,对压力旋流喷嘴内部流动机理及雾化特性进行了Fluent数字模拟研究。采用了一种基于有限容积VOF方法对压力旋流喷嘴内部流场进行了数值模拟;捕捉了压力旋流喷嘴出口处气-液两相界面,描述了压力旋流喷嘴出口的液膜厚度,阐述了压力旋流喷嘴各截面压力场、密度场和速度场等变化规律,预测了压力旋流喷嘴雾化锥角。模拟研究结果表明:压力旋流喷嘴中心会产生空气芯,压力旋流喷嘴雾化锥角及液膜厚度等雾化特征可通过剖析压力旋流喷嘴出口处空气芯直径和出口处速度获得;将模拟计算的喷嘴雾化锥角与试验值进行了对比,两者基本吻合,说明Fluent数值模拟可作为喷嘴设计工具。

Aiming at experimental study on the atomization characteristics of pressure swirling nozzle is high cost,long time and difficult to be realized in theoretical calculation,the internal flow mechanism and atomization characteristics of the pressure swirling nozzle were studied by Fluent digital simulation. The inner flow field of pressure swirl nozzle was simulated using the VOF model in order to investigate the flow mechanism and predict the atomization characteristics efficiently. The gas-liquid interface of the swirl nozzle exit was captured and the liquid film thickness at the outlet of nozzle was described. Variation of the different section fields of pressure,density and velocity in the nozzle was analysed and the spray cone angle of nozzle was predicted. The simulation results show that air core is created at the center of the pressure swirl nozzle and the out side atomization characteristics such as the spray cone angle and the thickness of the liquid film can be obtained by analyzing the air core diameter and speed at the nozzle exit. The spray cone angle of the simulated is compared with the trial value,which show they are reasonable. The Fluent numerical simulation can be used as a design tool for swirl nozzle.