experimental and numerical investigation of the effect of dimple and perforations on nusselt number and flow efficiency in multi-louvered heat exchanger

numerical and experimental analyses are performed on multilouvered fin banks in low and medium reynolds regimes to investigate the effects of dimples and perforations on flow structure and heat transfer capacity. in different reynolds numbers the flow efficiency has been calculated numerically and experimentally by flow visualization method and the results showed that dimples and perforations can increase flow efficiency more than 5% in fin banks. additionally, a set of numerical and experimental analysis has been done to evaluate temperature contours and total heat transfer in simple, dimple and dimple-perforation fin banks in different reynolds numbers. the simulations revealed that the heat transfer and temperature augmentations occur due to the existence of a circulation region that is created by the dimple. the results showed that adding dimples with perforations increased the heat transfer capacity of the fin banks up to 9% compared with the simple louver fin banks.