Numerical investigation on the orifice cavitating water jet considering the fluid viscosity’s effects on bubbles’ growth and collapse

Abstract

This paper attempts to investigate the effects of fluid viscosity on cavitation generation. Different from the traditional cavitation models in which the Rayleigh–Plesset equation is simplified neglecting the second-order term and the surface tension force term, the primitive R–P equations with different dynamic viscosity values are solved by mathematical software and numerical solutions are obtained. Then, the method of curve fitting is selected to get the approximate expressions of bubble radius about time. Based on the expressions, the rate of change of bubble radius about time under different viscous conditions can be approximately obtained which will be written as in-house code to enhance the traditional cavitation models by UDFs. Numerical simulations of high-speed water jets issuing from a nozzle are carried out. The simulated cavitation characteristics match the supercavity experiments very well. The result shows a more homogenous distribution of vapor volume fraction while the viscosity of fluid increases. The pressure and velocity also change more slowly and smoothly along the nozzle under more viscous conditions. Simulations of external flow fields are also made based on the modified model to show the cavitation characteristics under submerged condition.