有/无凹槽通道内煤油超燃雾化的测量研究

Measurements on kerosene atomization in supersonic flow in duct with and without cavity

关键词:  煤油雾化  超声速气流  Sauter平均直径  纹影

Key words:  Kerosene atomization  Supersonic flow  Sauter mean diameter  Schlieren

摘要:

为研究超燃流场中雾化煤油液滴直径分布,针对有/无凹槽(L/D=3)直通道,对煤油在超声速气流中的雾化过程进行了测量。利用纹影法得到雾化流场波系结构,利用平面激光诱导荧光(PLIF)得到煤油扩散范围,基于激光前向散射原理的激光粒度仪,得到液滴直径分布。结果表明,当来流和喷射条件相同,平板通道内的煤油射流穿透深度略大于凹槽通道。液滴直径呈在截面中心小、外侧大趋势,沿外侧的液滴直径波动较中心区大。煤油距喷口30 mm处已完成雾化,雾化区的液滴Sauter直径为4~8μm,凹槽对煤油穿透深度和雾化尺寸无明显贡献。

Abstract:

The distribution of the diameter of kerosene droplets in supersonic flow was measured to study the breakup and atomization phenomena of liquid jet in supersonic flow.Experiments were performed to study the atomization of kerosene jet in supersonic air-stream in a duct with and without a cavity(aspect ratio: L/D=3).Flowfield was visualized by schlieren to show shock wave structures.Planar laser induced fluorescence(PLIF) was applied to detect kerosene spreading.Droplet analyzer based on forward scattering principle was used to obtain distribution of droplets′ diameter.The results imply that penetration height in duct without cavity is a little larger than that with cavity at the same incoming and jet conditions.Just downstream the fuel nozzle,Sauter mean diameter(SMD) at the jet center is smaller than that at the periphery.The jet is almost fully atomized 30 mm downstream the fuel nozzle,SMD ranges from 4 to 8 microns,the cavity shows little contribution to jet penetration and atomization.