切欠きフィン付設流路内の熱流動特性

第2報, 切欠き配列迎え角の影響

抄録

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. Larger reduction of pressure loss ratio was obtained under smaller clearance conditions, while a smaller thermal resistance ratio was achieved with larger clearance by the cut-fins compared with fins without notches. A maximum peak, therefore, appeared in the overall performance in relationship to the clearance size. In the attack-angle effect case, larger heat transfer coefficients were obtained with smaller angles in both experimental and numerical results, particularly under larger Reynolds number conditions. A spanwise flow was generated in the area adjacent to the notch by inclining the notch array that effectively produced a longitudinal vortex like secondary flow and renewal of the thermal boundary layer at the trailing edge of the notch.