Investigation on flow and cavitation characteristics in flow channel of multistage depressurization valve

The multistage depressurization valve is extensively employed in nuclear power plants under high-pressure conditions, where cavitation failure often occurs during the passage of high-speed fluid through the valve. This article utilizes the Schnerr and Sauer cavitation model along with the realizable k–ε turbulent model to examine the internal flow and cavitation characteristics. The findings reveal that as fluid traverses the multistage channel, enhanced mixing processes and vortex structures emerge. Hedging and vortex dissipation significantly influence pressure reduction and energy dissipation within the flow channel. At the outlet of the final stage of depressurization, pressure rapidly decreases below the saturated vapor pressure, leading to the formation of cavitation. Due to the higher velocity at this position, the impact wear on the valve body is intensified. Therefore, increasing the outlet pressure of the valve proves effective in mitigating cavitation damage.