A new microlayer depletion model for numerical simulation of bubble growth during nucleate boiling

Abstract

In this study, a new microlayer depletion model was developed to simulate bubble growth during the nucleate boiling of water and ethanol. By improving the coupled volume-of-fluid and level set model, the macro-two-phase flow was accurately tracked, eliminating velocity jumps at the interface. The proposed model was validated against pool boiling measurements in water and ethanol at atmospheric pressure. The results demonstrated that the microlayer contributed approximately 15 and 33.17 % to the growth of water and ethanol bubbles, respectively. Under the influence of the interfacial temperature, the mass accommodation coefficient of water could vary from 0.004 to 0.027. Considering the impact of the interfacial temperature on the mass accommodation coefficient could reduce the prediction error of the evaporative thermal resistance from 17.2 to 4.67 %. Furthermore, the study revealed that the evaporative thermal resistance of the water is comparable to the microlayer conductive thermal resistance, whereas the maximum evaporative thermal resistance of ethanol is less than 5 % of the microlayer conductive thermal resistance and can be neglected.