双组元离心式喷注器的喷雾特性初步研究

利用激光粒子动态分析仪研究了某型双组元离心式喷注器的稳态和脉冲喷雾特性.用去离子水代替推进剂,测量了喷雾场不同截面上液滴的三维速度、平均直径和浓度分布.实验结果表明,内外喷嘴产生的两股液雾相互汇合在一起,液雾的运动速度、平均直径、浓度分布体现了空心锥喷雾的特点.脉冲喷雾与稳态喷雾轴向平均速度、脉动速度的分布特点是相同的,但在喷雾中心区域内脉动速度大于平均速度.脉冲喷雾时喷雾中心区域液滴直径分布很不均匀,平均直径的值在某个值附近脉动, 这是由于难以形成稳定而连续的液膜造成的.随着脉冲时间的减少,液雾速度和平均直径的不均匀性增强.研究结果可作为喷注器设计和喷雾数值模拟的参考.

Investigation on spray characteristics of bi-centrifugal swirl injector

The stable and pulse spray characteristics of a type of bi-centrifugal swirl injector were studied experimentally with particle dynamic analyzer.Properties of droplets such as velocities,size distribution,and volume flux were measured.The results show that the two sprays produced separately by the inner and outer nozzle converged to form one spray,which was as same as that of a simplex injector.The distributions of velocities, mean diameters and volume flux showed hollow cone spray characteristics.The velocities distributions of pulse spray were identical to that of stable spray,but the distinct difference was the RMS velocities were bigger than the mean velocities at the center zone of pulse spray.The Sauter mean diameters of pulse spray are bigger than that of stable spray.The poor atomization is due to the unstable and discontinuous liquid film formed in each nozzle at pulse conditions.The experimental results can provide important references to injectors design.