混合室结构对气泡雾化喷嘴喷雾特性的影响

利用激光颗粒动态分析仪对一种内旋流式气泡雾化喷嘴进行了实验测试与分析,探讨了混合室结构对喷嘴流量特性、颗粒平均直径分布特性、液雾平均速度分布特性的影响规律。气泡雾化喷嘴的流量特性主要受工作压力和喷口孔径影响,混合式结构对流量特性没有影响;但混合式结构对液雾颗粒平均直径分布和平均速度分布的影响十分显著,适当提高混合室长径比有助于减小液滴颗粒质量平均直径D10和索泰尔平均直径D32,同时可使液雾颗粒平均直径和平均速度的径向分布更加均匀;相对于渐缩型混合室,突缩型混合室可在一定程度上改善雾化效果,颗粒平均直径D10和D32径向分布均匀性更好,但喷雾主流平均速度略有降低。在喷嘴出口下游40~100mm时,液雾主流区域内的轴向平均速度未发生明显的速度衰减。

The Effect of the Mixing Chamber Structure ofEffervescent Atomizer to Spry Characteristics

The flow characteristics and spray characteristics of an effervescent atomizer with internal swirling flow structures were diagnosed by PDA. The influences of mixing chamber structures on spray characteristics were discussed. The main factors affecting the flow characteristics are working pressure and diameterof discharge orifice, and the influences of mixing chamber structures are negligible. However, the mixing chamber structure has a significant impact on the distributions of droplets mean diameter and velocity. Increasing the ratio of length to diameter appropriately is conducive to reduce the droplet mass mean diameter D10 and Sautermean diameter D32, and make the average axial velocity distribution uniform. Relative to the gradual contraction mixing chamber, the sudden contraction mixing chamber could improve the atomization quality to a certain extent. However, the axial mean velocity decreases slightly. Regarding the effervescent atomizer with internal swirling flow structures, the attenuation rate of axial velocity is not the main spray flow downstream discharge orifice 40mm to 100mm.