柴油机冷却水套空化两相流三维瞬态数值模拟研究

为了深入研究柴油机湿式气缸套振动引发穴蚀的机理和影响因素,在水套内部冷却液流动稳态数值模拟得到冷却液压力场与速度场的基础上,以完整单缸水套为研究对象,提取6缸稳态模拟结果作为边界条件.基于Mixture多相流模型与Singhal完全空化模型,采用动网格技术建立柴油机冷却液空化数值模拟的气液两相流仿真模型,进行冷却液空化...

3D Numerical Simulation of Cavitation Two-Phase Flow in Cooling Water Jacket of a Diesel Engine

In order to deeply study the mechanism and influencing factors of cavitation caused by the vibration of diesel engine wet cylinder liner, based on the steady-state numerical simulation of the coolant flow inside the water jacket to obtain the coolant pressure field and velocity field, the complete single cylinder water jacket was taken as the research object, and the six cylinder steady-state simulation results were extracted as the boundary conditions. Based on the multiphase flow model Mixture and the full-cavitation model Singhal, a gas-liquid two-phase flow simulation model for the numerical simulation of diesel engine coolant cavitation was established to carry out the transient numerical simulation of coolant cavitation. Results show that the pulse pressure of the coolant on the wall caused by vibration is the main cause of cylinder liner cavitation. The amplitude of the coolant pulse pressure increases with the wall vibration speed. The maximum pulse pressure appears at 6.75° when the vibration speed is the maximum. In a working cycle of the diesel engine, cavitation may occur on the main and secondary thrust side of the cylinder liner. And it is more likely to occur on the main thrust side. There are four areas on the main thrust side prone to cavitation, i.e. the upper middle, the top, the lower middle and the bottom from the greatest possibility to the lowest possbity of cavitation sorted by the amplitude of the pulse pressure on the wall. Finally, measures to reduce the risk of cavitation are proposed from the perspective of vibration suppression, cylinder liner surface modification and impulse pressure reduction.