Abstract:

Hydrophobic micro-pin fins with different contact angles are obtained by solidifying nano-particles involved hydrophobic coating on the surface of oval micro-pin fins. Pressure drop, friction factor f and Nusselt number Nu for different Reynolds numbers are measured. The impact of the variation of contact angles on heat sink flow resistance and heat transfer of micro-pin fins and energy efficiency characteristics are also analyzed comprehensive. Results demonstrate that hydrophobic coating has significant resistance reduction effect. Pressure drop and flow resistance coefficient decrease with the increase of contact angles. However, Nu in hydrophobic micro-pin fins also decreases, and Nu deviation in the three hydrophobic micro-pin fins increases with the increase of heat power. Although hydrophobic surface reduces Nu in micro-pin fins, superhydrophobic micro-pin fins with contact angle of 151.5° have better energy efficiency characteristics. Compared with those without hydrophobic coating, required pump power can be reduced by more than 200% for the same convective heat transfer.

Key words: Nusselt number, micro-pin fins, resistance reduction, energy efficiency, hydrophobic')">hydrophobic