Development of generalized bubble growth model for cavitation and flash boiling

Abstract

Cavitation occurs in a wide range of applications, such as in marine propellers, diesel injectors, supercavitating projectiles, etc. Currently, the available cavitation models rely on expressions derived from inertial bubble growth models and fine-tuned using a few experiments. Revisiting the literature on bubble growth models indicates that there is scope for improvement in the bubble growth expressions presently employed. The previous studies in this subject have assumed that the vapor in the bubble remains saturated. Detailed numerical studies using one-dimensional saturated vapor model reveals over-prediction of the bubble radius when compared with a wide range of experimental data. To overcome this, a coupled mass, momentum, and energy model, termed full model, is then developed and the analysis suggests that this model gives good agreement over the entire experimental data. Parametric studies carried out to generate non-dimensional bubble growth rate expressions indicate that the growth rate climbs linearly on a log –log plot during initial stages of bubble growth which is function Jakob number Ja and finally settles into an asymptotic non-linear curve which is independent of Ja. The bubble growth rate expressions when integrated to obtain bubble radius as function of time is able to predict the experimental data with mean relative error of 1.2% and root mean square relative error of 8% for Ja varying from 13.53 to 2745.