Numerical Study on the Influence of the Heating Substrate Thermophysical Properties on Bubble Growth and Bubble Influence Area

Abstract

Nucleate boiling is widely used in cooling systems in various industrial fields due to its highly efficient heat transfer ability. In nucleate boiling, bubble growth affects wall heat transfer significantly. To study the effect of bubble growth on the wall heat transfer process, a single bubble growth model with microlayer evaporation was established based on the Volume-of-Fluid (VOF) interface tracking method, and a dissipative microlayer model is embedded through user-defined functions to model the microlayer evaporation process. The effect of the thermophysical properties of the heating substrate on the wall heat transfer process was studied. The results showed that the wall temperature and bubble size predicted by the simulation method are similar to the experimental results. The study found that the thermophysical properties of the heating substrate had a significant impact on both the bubble growth process and the bubble influence area. Three stages were discovered in the evolution of the bubble influence area: microlayer-dominated stage, inertial expansion stage, and shrinkage stage. The study also found that the bubble influence factor (K) had a linear relationship with the thermal diffusivity of the heating substrate. The research results were of great significance for improving the wall heat flux partitioning model.

Keywords: Bubble growth, Bubble influence area, Microlayer evaporation, Nucleate pool boiling