Numerical Simulation Research Of Cooling Water Flow Cavitation Characteristics Of Cylinder Liner

Cavitation is one of the main forms of cylinder liner’s failure for diesel engine. It is closely related to the characteristics of the cooling water. In this paper, Based on the numerical simulation of the cooling water, we revealed the characteristics and development process of the cavitation flow, then analyzed the influence factors. The research results will be helpful to the analysis and improvement of the cylinder liner cavitation erosion resistance.Two dimensional numerical results show that the pressure and vapor volume fraction of the flow field around the cylinder are both consistent with the periodic vibration of the cylinder liner. The local flow field in the upper part of the cylinder wall is the main cavitation region. Consider the shape of the water jacket’s cross section, water temperature and thermodynamic which effect the characteristics of flow field. When the cooling water channel becoming narrow, under the same vibration frequency and amplitude, cavitation becomes serious, the cavitation degree increased. In temperature of 60 ℃ to 70 ℃, pressure on the cylinder is high, up to 90℃, the pressure fluctuation was significantly decreased. There are many factors which influence the bubble collapse pressure, Water density, bubbles’ surface tension, vapor density, water viscosity, etc. The cavitation model we have is for the isothermal process. Based on Singhal cavitation model, we established a new model considering thermodynamic effect. In evaporation, the thermodynamic effect correction term is negative due to the temperature drop, and the evaporation rate decreases. In condensation, the thermodynamic effect is positive and the condensation rate is increased. Compared with the original Singhal model, the modified one is calculated to obtain the reduced hole region and the lower vapor fraction.Through the three-dimensional numerical simulation of a diesel engine cylinder liner and cooling water, it turned out that, under the standard loading conditions, the maximum amplitude of the cylinder wall zone gas phase volume fraction and the wall pressure peak is small, this region cavitation effect is not serious, not enough to cause cylinder damage.