Hydrodynamic characteristics of the microlayer under vapour bubbles on solid surfaces

Abstract

This study investigates the hydrodynamic behaviour of the microlayer, a thin liquid film of a few micrometres thickness that forms beneath vapour bubbles during boiling under specific conditions. This microlayer serves as a rapid heat transfer medium through evaporation due to its low thermal resistance, making it a compelling subject for enhanced heat transfer research. We employ the geometric Volume-Of-Fluid (VOF) method for numerical simulations, allowing us to accurately replicate the growth of a vapour bubble on solid surfaces. The computational approach offers a level of detail and resolution that can compensate for certain aspects of microlayer behaviour absent in experimental methods. Our simulations reveal the complete spatial distribution of the microlayer and the profiles of the bubble interface near the meniscus front (the part of the interface near the solid). We compare the results with experimental data and conduct simulations with various bubble growth laws to explore how the microlayer responds to different growth scenarios. These findings lay the foundation for incorporating the microlayer’s contribution to overall boiling heat transfer in future models, potentially unlocking new avenues for enhanced heat transfer applications.