Investigation on Cavitation Flow in Pressure Relief Valve with High Pressure Differentials for Coal Liquefaction

Abstract

Taking the cavitation and cavitation erosion of pressure relief valve with high pressure differentials in the coal liquefaction project as the object of the study, the mathematical model for the three dimensional cavitation flow of the pressure relief valve is established. Based on the mixture model, the Schnerr-Sauer cavitation model and RNG k-ɛ turbulent model are used to simulate the three dimensional cavitation flows. The characteristics of the cavitation flow with different valve opening, different inlet pressure and out pressure are analyzed. The present work shows that there is severe cavitation at the throttle area of the disc and downstream. As the increase of the valve opening, the area and the rate of back flow which is close to the head of disc are both decreased, and the degree of cavitation in the valve is reduced. It is also found that cavitation in flow field would be gradually reduced in different degree while increasing the outlet pressure or decreasing the inlet pressure.