中心分级燃烧室慢车工况油雾场特性

Characteristics of fuel spray field in central staged combustor at idle condition

为获得中心分级燃烧室慢车工况下主副级油雾场特性,采用粒子图像测速仪(PIV)对单管燃烧室不同头部方案和不同喷嘴燃油比例的油雾场进行试验测量,开发了油雾场图像后处理软件,对油雾场图像进行后处理,获得了中心分级燃烧室油雾场空间分布。慢车工况下油雾场试验结果表明:大粒径油珠在燃烧室富油头部区域呈锥形分布,同时索太尔平均直径(SMD)沿径向呈V型分布,即中间小、两侧大。燃烧室头部折流板扩张角的减小,使得燃烧室富油头部区域油珠数目集中、同时平均SMD较大。保持来流条件和油气比一定时,改变燃油比例对燃烧室雾化效果影响不大。油雾场中油珠数目最多的粒径是25μm,而体积占比最大的粒径范围是30~50μm。

In order to obtain the characteristics of spray field of main stage nozzle and pilot nozzle of central staged combustor at idle condition,the particle image velocimetry(PIV)was used to measure the spray field of single-tube combustion chamber with different head schemes and different nozzle fuel ratios.And the post-processing software of spray field image was developed,the spatial distribution of the spray field was obtained by extracting oil droplets on raw pictures in the central graded combustion chamber.The research of spray field under idle condition indicated that:large-size droplets were distributed in a conical shape in the fuel-rich head area of the combustion chamber,while the Sauter mean diameter(SMD)was distributed in a V-shaped radial direction,namely,small in the middle and large on both sides.The reduction of the expansion angle of the baffle made the number of droplets concentrated in the fuel-rich head area of the combustion chamber and the average SMD was larger.When the incoming flow conditions and the fuel-air ratio were kept constant,changing the fuel ratio had little effect on the atomization effect.The particle size with the largest number of droplets in the spray field under idle conditions was 25μm,and the particle size range with the largest volume ratio was 30−50μm.