Notch Arrangement Effects on Heat Transfer Characteristics in a Channel with Cut-fins

Abstract

The effects of the attack-angle of the fin notch array against the main flow and size of the clearance at the fin-tip on the heat transfer and pressure loss performances of a channel with cut-fins (parallel fins with square notches) mounted on the bottom wall were evaluated in the present article. Three-dimensional numerical simulations and heat transfer experiments employing a modified single-blow method were conducted to discuss these characteristics. As the size of the clearance was decreased, the pressure loss reduction effect in the cut-fins case compared with the plain-fins case (parallel fins without notches) was increased. On the contrary, smaller thermal resistance ratio between the cut-fin and plain-fin cases was achieved with larger clearance size. A maximum peak, therefore, appeared in the overall performance in relation to the clearance size. Larger heat transfer coefficients were obtained with smaller attack-angles of the notch array in both experimental and numerical results, particularly under larger Reynolds number conditions. This was due to the spanwise flow generated in the area adjacent to the notch, by which renewal of the thermal boundary layer was effectively produced at the trailing edge of the notch.

Keywords

• cut-fin
• compact heat sink
• notch array angle effect
• clearance size effect
• single-blow method
• numerical simulation