Study on the Collapse Process of Cavitation Bubbles Including Heat Transfer by Lattice Boltzmann Method

摘要

In this study, an improved double distribution function based on the lattice Boltzmann method (LBM) is applied to simulate the evolution of non-isothermal cavitation. The density field and the velocity field are solved by pseudo-potential LBM with multiple relaxation time (MRT), while the temperature field is solved by thermal LBM-MRT. First, the proposed LBM model is verified by the Rayleigh–Plesset equation and D2 (the square of the droplet diameter) law for droplet evaporation. The results show that the simulation by the LBM model is identical to the corresponding analytical solution. Then, the proposed LBM model is applied to study the cavitation bubble growth and collapse in three typical boundaries, namely, an infinite domain, a straight wall and a convex wall. For the case of an infinite domain, the proposed model successfully reproduces the process from the expansion to compression of the cavitation bubble, and an obvious temperature gradient exists at the surface of the bubble. When the bubble collapses near a straight wall, there is no second collapse if the distance between the wall and the bubble is relatively long, and the temperature inside the bubble increases as the distance increases. When the bubble is close to the convex wall, the lower edge of the bubble evolves into a sharp corner during the shrinkage stage. Overall, the present study shows that this improved LBM model can accurately predict the cavitation bubble collapse including heat transfer. Moreover, the interaction between density and temperature fields is included in the LBM model for the first time.