Simplified Model for Prediction of Bubble Growth at Nucleation Site in Microchannels

Abstract

Formation of the first bubble at nucieation site is an inception of the two phase flow in pool boiling and flow boiling. Bubble dynamics (bubble nucieation, growth, and departure) plays an important role in heat transfer and pressure drop characteristics during rv,'o phase flow in microchanneis. In this paper, a simplified model has been developed for predicting bubble growth rate at nucieation cavity in microchannel. It is assumed that heat supplied at nucieation site is divided between the liquid phase and the vapor phase as per instantaneous void fraction value. The energy consumed by the vapor phase is utilized in bubble growth and overcoming resistive effects; surface tension, inertia, shear, gravity, and change in momentum due to evaporation. Proposed model shows a good agreement with available experimental works. In addition, the bubble waiting time phenomenon for flow boiling is also addressed using proposed model. Waiting time predicted by the model is also close to that obtained from experimental data.

Study on microchannel cavitation phenomena based on experiment and simulation

“…Among them, Barber J et al [10] found through experimental research that fluid velocity, pressure and channel size are important parameters affecting cavitation phenomenon in microchannels. In addition, Kadam S T [11] used numerical simulation methods to analyze in detail the flow characteristics of bubble formation, growth and shedding in microchannels, providing important clues for further understanding of the mechanism of cavitation in microchannels.…”