Cavitating flows in microchannel with rough wall using a modified microscale cavitation model

Abstract

Cavitation can induce drastic disruption and significantly enhance heat transfer, especially in microchannels. However, due to the scale effect, the cavitation characteristics in micro-scale can be significantly different from those in conventional scale. A modified cavitation model according to the Rayleigh-Plesset bubble kinetic equation is formulated by including the effects of surface tension, and temperature difference between the local environment and the far-field environment. The impacts of latent heat of vaporization and condensation are introduced into the energy equation. The micro-scale cavitation model proposed in the paper is verified through comparison with experimental data. The influence of surface roughness on cavitation flow in microchannel with restrictor is then investigated. The results demonstrate that bottom surface roughness in microchannels significantly increases flow resistance, suppresses cavitation flow and causes high frequency pressure fluctuations.