液气式针栓喷注单元喷雾场结构试验研究

Experimental Research on Spray Field Structure of Liquid-Gas Pintle Injector Element

关键词:  针栓喷注单元  喷雾形态  喷雾角  粒径分布  速度分布

Key words:  Pintle injector element  Spray pattern  Spray angle  Droplet diameter distribution  Velocity distribution

摘要:

径向孔型针栓喷注器相对于径向缝型针栓喷注器具有更复杂的喷雾场。为了研究径向孔型针栓喷注器的喷雾场结构，将径向孔型针栓喷注器简化为单个气体射流与液膜碰撞的针栓喷注单元，采用了背景光成像系统结合激光相位多普勒技术（PDA），以水和空气为模拟介质，对液气式针栓喷注单元的喷雾场进行了试验研究。试验结果表明，液气式针栓喷注单元喷雾的三维结构呈现“喇叭”状。根据喷雾的形成过程及液滴的分布，液气式针栓喷注单元喷雾可以划分为4个区域：碰撞区、液滴区、液雾区及液丝区。液气式针栓喷注单元喷雾的分布范围可由内边界角、外边界角、中线角及散布角表示，均随局部动量比的增大而增大。液滴区的粒子主要由碰撞过程产生，SMD较大；液雾区的粒子经碰撞过程产生后，在气动力作用下进一步雾化，SMD小。由于液雾区的速度和粒径同时受到气动力作用的影响，粒径分布与速度分布在空间上呈现负相关趋势。

Abstract:

The pintle injector with radial orifice has a more complex spray field than the pintle injector with radial slot. In order to study the spray field structure of the pintle injector with radial orifice， the pintle injector was simplified to an injector element in which a single gas jet collides with the liquid film. The background light imaging system and phase Doppler anemometry （PDA） were adopted. Water and air were adopted as simulation medium ， and an experimental study was carried out on the spray field structure of the liquid-gas pintle injector element. The experimental results show that the three-dimensional spray field structure of the liquid-gas pintle injector element is in the shape of a ‘horn’. According to the formation process of the spray and the distribution of droplets， the spray field of the liquid-gas pintle injector element can be divided into four areas： collision zone， droplet zone， fog zone and ligament zone. The distribution range of the liquid-gas pintle injector element spray can be defined by inner boundary angle， outer boundary angle， midline angle and dispersion angle. All increase with the increase of local momentum ratio. The droplets in the droplet region are mainly produced by the collision and the SMD is relatively large. The droplets in the fog area are further atomized by the aerodynamic force after they are produced by the collision process， so the SMD is relatively small. The droplet diameter distribution and the velocity distribution show a negative correlation trend on fog area because the velocity and droplet diameter are both affected by the aerodynamic effect.