船舶柴油机喷油泵柱塞穴蚀机理的数值仿真研究

Numerical Simulated Investigation of Cavitation Phenomenon on Plunger of Fuel Injection Pump

针对船舶柴油机喷油泵柱塞螺旋槽上方壁面的穴蚀现象,建立了喷油泵柱塞与套筒模型,利用FLUENT软件对喷油泵内流场进行数值仿真计算,重点研究局部低压区、湍流涡团以及气泡析出、成长和溃灭过程。研究结果表明,柱塞螺旋槽与套筒回油孔构成的重叠开口的大小和形状对燃油流场具有决定性影响,产生低压区和湍流,生成的气泡溃灭时对柱塞螺旋槽上方壁面和回油孔内壁产生机械冲击,造成穴蚀。

Aiming at the cavitation phenomenon on the wall of the plunger just above the helical groove, this paper built plunger and barrel model, and carried out numerical computation on the fluid field flowing through the overlap opening between the plunger and oil return hole in the barrel with FLUENT software. The focus of this research was to explore local low pressure, turbulent eddy, as well as the bubble precipitating, developing and collapsing. The results show that the fuel fluid field in the pump is mainly influenced by the shape and value of the overlap opening, which contributes to cause low pressure and turbulence with the consequence of producing bubbles. When the bubbles collapse, mechanical impacts act on the wall of the plunger and the inner wall of oil return hole in the barrel and cause cavitation.