船用柴油机高压喷嘴空穴流动的瞬态数值分析

摘要

In order to study the high-pressure common-rail marine diesel engine transient flow and cavita-tions inside the nozzle, the injector nozzle transient flow of a certain type of marine diesel engines have been calculated by using CFD software. The liquid velocity, pressure, turbulent kinetic, and the gas vol-ume fractions inside injection nozzles with different common rail pressures and different diameters of noz-zles were calculated. Analysis results show that the small diameter of nozzle hole can increase the initial disturbance level of the liquid core surface, and increase primary breakup disintegration, and the small diameter of nozzle hole can improve fuel atomization. The higher common-rail pressure can increase the relative speed of gas/liquid two-phase, and is helpful to improve the primary breakup of liquid core.%利用CFD软件对某型船用柴油机高压喷嘴内部的瞬态流动进行了数值研究，计算得到了不同喷孔参数和不同共轨压力下喷嘴内部的液相速度、压力、湍动能以及气相体积分数(空穴)的分布情况。结果表明，在相同轨压下小孔径喷孔可以加强液柱表面的初始扰动水平，增强液柱的初次破碎能力，有利于燃油雾化；高的共轨压力加大了气液两相间的相对速度，有助液柱的初次破碎。