液态LPG喷射发动机喷嘴内部气穴现象的数值解析

建立了描述液态LPG燃料性质的13种物化参数的数据库,并将其编译导入通用CFD软件Fire 8.5.在验证了解析方法可行性的基础上,数值解析了液态LPG喷嘴内部在不同喷孔形状时的气穴现象,考察了气穴生成的位置、喷孔出口处的燃料体积分数的分布等.结果表明:单孔喷嘴内部的气穴发生在喷孔入口拐角处,气穴生成区域呈圆周均匀分布,并且一直延伸至喷孔出口;而双孔喷嘴内部的气穴总是发生在与垂直来流方向呈锐角分布的两喷孔入口处,随着流动的发展,气穴生成区域迅速地向喷孔中心扩散.无论是单孔还是双孔LPG喷嘴,气穴现象使得实际的喷孔流通截面积发生变化.

Simulation of Cavitation Phenomenon in Injector of Liquid Phase LPG Engine

The cavitation formed in injector of liquid phase liquefied petroleum gas (LPG) engine was investigated by using FIRE CFD code, and a database describing LPG fuel properties was built up and imputted into the code. The formation of cavitation in injector nozzle holes with different geometry was simulated, and the parameters, such as the vapor void fraction, the pressure and velocity distribution at the nozzle hole outlet and the cavitation location, were examined. The results show that for the single-hole injector, the cavitation occurs at the entrance of nozzle hole and appears as uniform distribution along the wall in cross section. Meanwhile, for the double-hole injector, the cavitaiton always occurs at the entrance of both nozzle hole and appears as sharp angle distribution and then gradually develops toward the outlet of nozzle holes. As a result of cavitation, the effective cross flow area of nozzle hole will be decreased.