Do surfaces with mixed hydrophilic and hydrophobic areas enhance pool boiling?

TL;DR

This study shows that surfaces with mixed hydrophilic and hydrophobic areas significantly improve pool boiling heat transfer and critical heat flux, with specific network patterns providing optimal performance.

Contribution

It introduces and characterizes novel patterned surfaces combining hydrophilic and hydrophobic regions, demonstrating enhanced boiling performance over traditional surfaces.

Findings

Critical heat flux increased by up to 65%

Heat transfer coefficient improved by up to 100%

Hydrophilic networks prevent vapor layer formation

Abstract

We demonstrate that smooth and flat surfaces combining hydrophilic and hydrophobic patterns improve pool boiling performance. Compared to a hydrophilic surface with 7 degree wetting angle, the measured critical heat flux and heat transfer coefficients of the enhanced surfaces are up to respectively 65 and 100% higher. Different networks combining hydrophilic and hydrophobic regions are characterized. While all tested networks enhance the heat transfer coefficient, large enhancements of critical heat flux are typically found for hydrophilic networks featuring hydrophobic islands. Hydrophilic networks indeed are shown to prevent the formation of an insulating vapor layer.