Improvement of Mass Transfer Rate Modeling for Prediction of Cavitating Flow

Abstract

This study proposes and investigates the impact of a modification, accounting for the influence of vortices and flow properties on the liquid rupture, to improve the modeling of mass transfer rate in cavitation. The threshold phase-change pressure is calculated by the fluid-saturated pressure at rest and the added vortex pressure term. The explicit simulation of the fully turbulent, homogeneous compressible, cavitating flow around the NACA0015 hydrofoil and the hemispherical body is performed. Saito cavitation model and Wilcox k-ω turbulence model are implemented for the evaluation of the proposed modification. The pressure coefficient distribution -Cp and cavitation behavior, including the vapor formation-collapse processes and the flow mechanism, are investigated. The analysis shows that the present modification, coupled the local flow viscosity with the vorticity magnitude, making the cavitation model better sensitive to the flow condition. The modification has a weak impact on the steady sheet cavitation around a hemispherical body but is the key factor underlying the improvement in the predicted complex flow around the NACA0015 hydrofoil. In that, the predicted -Cp and cavity structure around the hydrofoil is improved in comparison with the existing numerical data by other research groups and that by the Singhal turbulent pressure fluctuation model.