结构参数对可调节针栓喷注器喷雾特性的影响

Effects of structural parameters on the spray characteristics of variable pintle injectors

为揭示结构参数对可调节针栓喷注器喷雾特性影响规律,综合采用高速摄影和Malvern技术,对液/液针栓喷注器进行雾化试验,分析阻塞比、套筒扩张角等结构参数对流量系数、喷雾锥角和SMD等指标的影响。试验结果表明:阻塞比和套筒扩张角对流量系数影响较大;动量比相同时,阻塞比对喷雾锥角、SMD及空间分布影响较为显著,是由于局部动量比改变所致,阻塞比越大,喷雾锥角越小,SMD越大;喷雾越往下游发展,SMD越小;套筒扩张角会对喷雾锥角、SMD产生影响,套筒扩张角越大,喷雾锥角越小,SMD越大,套筒扩张角降低至小于90°时,SMD会明显降低。通过上述结果可以发现,在一定的动量比下,采取氧化剂中心式针栓喷注器适当增大、燃料中心式针栓喷注器适当减小阻塞比和套筒扩张角的方法,可获取合适的喷雾空间分布和滴液尺寸,实现喷雾雾化性能的提升。

To reveal the influence of structural parameters on the spray characteristics of variable pintle injectors,the cold atomization experiments of liquid/liquid pintle injector were carried out by using high-speed photography and Malvern techniques.The effects of geometrical parameters,such as blockage factor and sleeve expansion angle on flow characteristics,spray angle and SMD were analyzed.The experimental results show that the geometrical parameters such as blockage factor and sleeve expansion angle have great influence on the flow coefficient.Under the same momentum ratio,the blockage factor has a significant effect on the spray angle,SMD and spatial distribution of SMD,which may be caused by the change of local momentum ratio.The further downstream the spray goes,the smaller the SMD is.Lager sleeve expansion angle leads to smaller spray angle and lager SMD.When the sleeve expansion angle is less than 90°,SMD will decrease significantly.From the above results,it can be found that at a certain momentum ratio,the proper spray distribution and droplet size were obtained by properly enlarging blockage factor and sleeve expansion angle of oxidant center pintle injector,or decreasing blockage factor and sleeve expansion angle of fuel center pintle injector,to improve the atomization performance.