Capillary-driven evaporation enables thermal management for confined electronic devices needing high heat flux and temperature uniformity, with the thin-film region near three-phase contact lines contributing 50-80% of total heat transfer. Its maximum thickness (δ_tf,max), a key parameter for evaporation capacity, is conventionally 1-10 μm but lacks precise prediction methods.This work proposes an empirical model for δ_tf,max in such evaporation, with ±20% accuracy. Combining CFD simulations and theoretcal analysis, it quantifies effects of geometry, contact angles, and liquid thermophysical properties. Applied to predict optimal wicking geometries maximizing interfacial heat flux for water, ethanol, and isopropanol, the model fills the theoretical gap in δ_tf,max prediction.
 

Capillary-driven evaporation,Equivalent maximum thickness,Heat transfer model,Thin-film region,Thermal management