Heat transfer characteristics of a hydrophilic-modified flat heat-pipe-spray-cooling system

Abstract This paper proposes a cooling method that combines hydrophilic modification of heat pipe condensation section. Five surfaces with varying wettability (contact angles: 3.7°, 21.2°, 40.6°, 59.7°, and 75.1°) are prepared via electrostatic spraying of PU (polyurethane)/SiO2/DMF (N,N-dimethylformamide) solutions. Experiments and simulations show the best performance at a 20° contact angle, where the heat transfer coefficient increases by up to 29.6% and thermal resistance decreases by 22.9%. The results indicate that a 20° contact angle is optimal for efficient heat dissipation.