Physical Model of a Single Bubble Growth during Nucleate Pool Boiling

Abstract

A simplified physical model of a single bubble growth during nucleate pool boiling was developed. The model was able to correlate the experimentally observed data of the bubble’s growth time and its radius evolution with the use of the appropriate input parameters. The calculated values of separated heat fluxes from the heater wall, thermal boundary layer, and to the bulk liquid gave us a new insight into the complex mechanisms of the nucleate pool boiling process. The thermal boundary layer was found to supply the majority of the heat to the growing bubble. The heat flux from the thermal boundary layer to the bubble was found to be close to the Zuber’s critical heat flux limit (890 kW/m2). This heat flux was substantially larger than the input heater wall heat flux of 50 kW/m2. The thermal boundary layer acts as a reservoir of energy to be released to the growing bubble, which is filled during the waiting time of the bubble growth cycle. Therefore, the thickness of the thermal boundary layer was found to have a major effect on the bubble’s growth time.

Simulation of single bubble dynamic process in pool boiling process under microgravity based on phase field method

“…Cheng et al [19] simulated the two-dimensional bubble growth under the condition of supercooled nucleate boiling by using the fluid volume method (VOF), and based on this, studied the bubble shape and temperature field. Voglar et al [20] established a simplified physical model that can associate the bubble growth time with other input parameters. The results show that the thickness of the thermal boundary layer has a significant impact on the bubble growth time.…”