外混式双流体雾化器荷电喷雾流场特性

Measurement of charged spray flow field for external mixing twin-fluid nozzle by PIV

利用PIV技术对气液两相流场与电场耦合作用下的外混式双流体雾化器荷电喷雾流场特性进行了测量研究,设计了一种带环形气幕的荷电感应装置,以控制喷雾射流在感应荷电过程中出现的液滴卷吸.结果表明:当水流量Q由20 L·h-1增加到36 L·h-1时,射流核心区速度增大,喷雾结构逐渐呈现非对称性,随着流量的增大非对称性越明显;扇形压力pR、雾化压力pB对喷雾流场的对称性及喷雾锥角的变化起重要作用;高压静电作用使得喷雾锥角略微增大,上卷吸现象明显并出现涡旋结构,长时间工作时电极环易积液;电极环气幕压力为100 k Pa时,其低压气流可以有效弱化细小液滴的上卷吸运动,解决电极环积液问题,荷电双流体雾化器运行稳定.

The PIV technology was applied to investigate the spray field structure of charged twin-fluid nozzle under coupling interaction of gas-liquid two-phase flow field and electric field.In order to solve the problem of droplets sucking back by electrode ring during induction charging process,a ring-shaped aircircuit electrostatic induction device was designed.The results show that the speed of jet core area is increased when liquid flow rate of Q increases from 20 L·h-1to 36 L·h-1,and the spray structure becomes more asymmetric with the increasing of liquid flow rate.Fan pressure and atomization pressure play important roles in the changes of spray cone angle and spray symmetry.The spray cone angle slightly increases,and the vortex structure emerges under the effect of high electrostatic voltage field.The charged electrode ring is surrounded by tiny droplets because of up convolution movement.When the air pressure of electrostatic ring is 100 k Pa,the low-pressure wind issued from charged electrode ring can effectively weaken the up covolution movement,and the twin-fluid atomizer can be stably operated for long-term.