Optimization of fin arrays in an inclined channel for mixed convection

Abstract

In this study, mixed convection heat transfer in an inclined parallel-plate channel with transverse fins attached on wall surfaces is investigated numerically. Fluid flows with two special cases of natural and forced convection in the channel are also studied respectively to obtain the maximum heat transfer rates of fins and their corresponding aspect ratios. The effects of thermal conductivity of fins and inclination angles of the channel are taken into consideration. For the arrays with seven fins are arranged on both upper and lower walls in a staggered form. The recirculating eddies behind the last fins on the upper wall will diminish and even vanish eventually as the inclination angles of the channel increases particularly when natural convection is dominant. With the frontmost fin mounted on the lower wall, the average optimum fins on this wall turn out to be a little shorter and fatter than those on the opposite wall. For a fixed ϕ, the optimum aspect ratios of fins attached on lower wall, upper wall, or both walls increase with Gr/Re2. The optimum fins turn out to be shorter and fatter for a smaller K but longer and thinner for a larger K. In addition, the optimum aspect ratios of fins in a channel increase with ϕ particularly for natural convection. Finally, the correlations of the optimum aspect ratios of arrayed-fins are proposed for the parallel-plate channel with various inclination angles.