Cavitation bubble collapse between parallel rigid walls with the three-dimensional multi-relaxation time pseudopotential lattice Boltzmann method

Studying the flow characteristics of bubbles in a narrow gap is an important problem related to bearing cavitation and gas–liquid two-phase flow. In this paper, we present a modified three-dimensional multi-relaxation-time pseudo-potential model for large density ratio multiphase phenomena. The accuracy of the model is verified by the Maxwell construction, Laplace law, and Rayleigh–Plesset equation. The influence of the force scheme parameter and the dimensionless relaxation time on the thermodynamic consistency of the model is analyzed. The results show that the three-dimensional lattice Boltzmann pseudo-potential model proposed in this paper has good numerical stability in simulating multiphase phenomena. Furthermore, the cavitation bubble collapse process between parallel rigid walls is simulated by the proposed model. The collapse process obtained by the present method agrees well with the experimental result. The different orientations for the bubble to the wall exert a significant influence on the variation of the pressure field, velocity field, and evolution of maximum pressure and micro-jet velocity. During the cavitation bubble collapse process, the pressure and the velocity at the collapse point will increase instantaneously, and the orientation for the bubble to the wall is a key factor to determine the collapsed form of the cavitation bubble. The results verified the practicability of the addressed model to study the collapse of three-dimensional cavitation bubbles in the presence of parallel rigid walls.