Theoretical and experimental study of the heterogeneous bubble nucleation in boiling of pure liquids and binary mixtures based on Gibbs free energy analysis and heated surface characteristics

Abstract

The onset of nucleate boiling (ONB) conditions significantly impact the performance of boiling heat transfer. Predicting and optimizing these conditions is crucial in various industrial applications. In this paper, the nucleation critical conditions for the heterogeneous boiling nucleation of both pure liquids and mixed liquids are established based on the stricter critical nucleation criterion of dΔG^hetero/dr = 0. Additionally, a computation approach for predicting the ONB conditions of heterogeneous boiling in non-visible situations is developed by considering the characteristics of heated surface morphology and heat transfer. An experimental setup is constructed to validate the computational method by measuring the ONB superheat and heat flux of pure liquid and binary mixtures. The results demonstrate that the error between the model calculations and experimental values is within the range of ±20 %. Moreover, insights into the control mechanism of regular cavity surfaces on ONB conditions and nucleation sites are obtained, leading to the development of techniques for manipulating surface conditions to optimize the ONB. The findings reveal that as the wall superheat increases, the surface with regular micro-cavities shows a significantly lower transient change in nucleation density.