Thermal Effect on Dynamic Evolution of Cavitation Flows through a Cryogenic Butterfly Valve

In cryogenic butterfly valves, the obstruction caused by the valve core leads to the localized pressure drop in flow of cryogenic media. This cavitation phenomenon is induced when the localized pressure of the cryogenic medium falls below the saturation vapor pressure corresponding to the local temperature. In comparison to the fluid medium with normal temperature, the thermal sensitivity of cryogenic media affects the precision of the numerical simulations for cavitation flow fields at cryogenic conditions when employing conventional cavitation models. In this study, the traditional Zwart–Gerber–Belamri (ZGB) cavitation model is modified by considering the thermal effect of cryogenic medium. A modified cavitation model is obtained to accurately predict cryogenic cavitation flows and verified by experimental results. By utilizing the modified cavitation model and large eddy simulation model, the cavitation flow field and the cavitation evolution of liquid nitrogen through a cryogenic butterfly valve was studied at various temperatures and the valve opening degree of 80%. Using the ω-criterion, the spatial and temporal correlations between the cavitation and vortex structures are discussed and analyzed in detail.