Performance analysis of a heat exchanger having perforated square fins

The present paper reports on heat transfer enhancement and the corresponding pressure drop over a flat surface equipped with square cross-sectional perforated pin fins in a rectangular channel. The channel had a cross-sectional area of 100-250 mm². The experiments covered the following range: Reynolds number 13,500-42,000, the clearance ratio (C/H) 0, 0.33 and 1, the inter-fin spacing ratio (S_y/D) 1.208, 1.524, 1.944 and 3.417. Correlation equations were developed for the heat transfer, friction factor and enhancement efficiency. The experimental results showed that the use of the square pin fins may lead to heat transfer enhancement. Enhancement efficiencies varied between 1.1 and 1.9 depending on the clearance ratio and inter-fin spacing ratio. Both lower clearance ratio and lower inter-fin spacing ratio and comparatively lower Reynolds numbers are suggested for higher thermal performance. Using the Taguchi experimental design method, optimum design parameters and their levels were investigated. Nusselt number and friction factor were considered as performance parameters. An L₉(3³) orthogonal array was selected as an experimental plan. First of all, each goal was optimized, separately. Then, all the goals were optimized together, considering the priority of the goals. Finally, the optimum results were found to be Reynolds number of 42,000, fin height of 50 mm and streamwise distance between fins of 51 mm.