Heat flux characteristics during growth and collapse of wall-attached cavitation bubbles with different wall wettability: A lattice Boltzmann study

A thermal lattice Boltzmann method is used to examine the heat flux characteristics of the growth and collapse of wall-attached cavitation bubbles under different wall wettability and temperature conditions. We consider the mutual influence of the temperature field and flow field to understand the effect of the wall temperature on the dynamic contact angle. The wettability of the wall exerts a great influence on the bubble morphology, with higher expansion velocities observed on non-wettable walls during the growth stage. The contact point is pinned due to the hysteresis effect, leading to a weaker collapse intensity on non-wettable walls. The present model obtains the thermal delay phenomenon caused by the supply of latent heat from the surrounding liquid to the bubble. Additionally, the efficiency of the temperature increase through the phase change is lower than that of wall cooling from a cooled wall, resulting in a low temperature at the contact point. Finally, for the wall-cooling processes, wettable walls reduce the deterioration of heat transfer efficiency during the growth stage and enhance the heat transfer efficiency during bubble collapse.