Effect of Shape and Placement of Twisted Pin Fins in a Rectangular Channel on Thermo-Hydraulic Performance

To enhance the thermo-hydraulic performance of cooling channels,this investigation examines the influence of distinct cross-sectional shapes(i.e.,triangular,rectangular,and hexagonal) of twisted pin fins and their arrangements in straight and cross rows.An ambient air cooling test platform was established to numerically and experimentally investigate the flow and heat transfer characteristics of 360° twisted pin fins at Re=15 200-22 800.The findings reveal that straight rows exhibit higher Nu values than cross rows for triangular and rectangular twisted pin fins,and Nu increases with Re.In contrast,for hexagonal twisted pin fins,only straight rows at Re=19 000 exhibit superior overall thermal performance compared to cross rows.Notably,the heat transfer performance of the cooling channel with hexagonal twisted fins surpasses both triangular and rectangular configurations,especially at high Reynolds numbers(Re=22 800).Although the heat transfer coefficient of the cooling channel with hexagonal twisted fins is significantly enhanced by 132.71% compared to the flat channel,it also exhibits the highest thermal resistance and relative friction among the three types of twisted fins,the maximum of which are 2.14 and 16.55.Furthermore,the hydrothermal performance factor(HTPF) of the cooling channels with different types of twisted pin fins depends on the Reynolds number and arrangement modes.At Re=15 200,the highest HTPF achieved for the cross-row hexagonal twisted pin fins is 0.99.