Pool boiling Mechanisms over Micro-textured Surfaces
The rate at which bubbles are generated and released from the surface are important parameters to delay the critical heat flux (CHF) and to increase the heat transfer coefficient (HTC), which depend on the thermo-physical properties of the liquid and surface material, on the dynamics of wettability and on the surface micro-geometry.
Both the advancing and the receding contact angles play an important role: highly wetting fluids produce less nucleation sites and facilitate the subsequent rewetting of the dry surface as bubbles lift off the boiling surface, while promoting evaporation during bubble growing, as the vapour pushes liquid away to create a larger dry patch.
The dynamics and thermal transport along the triple contact line solid-liquid-vapor at the leading edge of the liquid film is, therefore, of particular importance as it drives the entire boiling process.
Surface Enhancement for the Control of
Interfacial Transport Phenomena
ENGINEERED SURFACES FOR HEAT TRANSFER ENHANCEMENT
The presence of chemical inhomogeneity, roughness or any microscale structure on the surface can significantly change the dynamics of wettability, the equilibrium contact angle and rate of evaporation, depending on the relative scales and is currently a strategy widely studied to control and enhance heat transfer efficiency. This remains the subject of intensive research of, both experimentalists and theorists, particularly for engineered surfaces.