Abstract: To investigate the spray characteristic in the combustion chamber of the low thrust liquid rocket engine，the small scale simulation chamber and the impinging nozzle were designed. The impinging spray was ob.served with the PDA system. The effects of the pressure on the spray parameters were analyzed emphatically. Theresults indicate that，the further away from the nozzle，the larger the mean diameter of the droplets is and the lowerthe axial velocity is. The further the measuring point from the center axis is，the smaller the axial velocity of thedroplets is and the more the fluctuation of the radial velocity is. The greater the nozzle pressure is，the smaller the mean diameter of the droplets is and the higher the axial velocity is. Under the influence of the chamber wall，the effects of the spray pressure and the measuring point location on the circumferential distributions of the radial ve.locity are not obvious. The mean diameter of the droplets in the simulation chamber is larger than that in atmo.sphere environment，and the difference increases as the spray develops downstream. The simulation chamber af.fects the axial velocity of the droplets slightly，but the radial velocity seriously.

Key words: Impinging nozzle；Spray；Droplet；Small scale space；Circumferential distributions

摘要： 为了研究小推力液体火箭发动机燃烧室的喷雾燃烧特性，设计了小尺度模拟燃烧室和对撞射流喷嘴，利用多普勒相位粒子动态分析仪( PDA)，观测了对撞射流在小尺度空间内的喷雾，重点观测了喷雾压力对于雾化特性参数的影响。实验结果表明:测量截面与喷嘴的距离越远，液滴平均直径越大，轴向速度越小；测量点到中心轴的距离越远，液滴轴向速度越小，径向速度波动越大；喷雾压力越大，液滴平均直径越小，轴向速度越大。由于受到壁面的影响，径向速度的周向分布在不同的喷雾压力下和测量点位置上的差异不明显；模拟燃烧室内液滴平均直径大于大气环境下的液滴平均直径，两者差值随着喷雾向下游发展而增大；模拟燃烧室对于液滴轴向速度影响较小，而对于液滴径向速度影响较明显。

关键词: 撞击式喷嘴；雾化；液滴；小尺度空间；周向分布