Numerical simulation of forced convection heat transfer mechanism and comprehensive performance on hydrophobic structure surface

Abstract

The numerical simulation of the hydrophobic structured surfaces is conducted in this work to investigate the confined effects of heat transfer performance and forced convection resistance. A new heat transfer model of air cavities is established based on the cavitation heat transfer process. Four structures (i.e., longitudinal ridges, square posts, square holes and transverse ridges) are constructed to study the effect of air cavities and slip-velocity on heat transfer. The goodness factor φ is utilized to evaluate the overall performance of the hydrophobic structured surfaces with different geometries. The results show that the existence of air cavities produces a negative effect of heat transfer, and the slip-velocity can enhance heat transfer performance. However, the coupling effect of air cavities and slip-velocity is related to surface structure rather than linear superposition. In addition, the heat transfer performance and frictional resistance, as well as goodness factor are dependent on the structure and contact angle of hydrophobic surface. Compared with the smooth surface, the hydrophobic surfaces for all structures exhibit a better goodness factor, and the maximum φ/φ0 of 1.105 can be achieved on the square posts structure.