Thermal performance of louvered fin heat exchanger with unequal louver pitch

We manufactured scaled-up louvered fin in which the louver pitch continuously increased by 20% from air inlet area to the redirection region and analyzed the thermal performance of equal and unequal louver pitch louvered fin heat exchanger. The time, the heat transfer rate of louvered fin heat exchanger reached 50% of the maximum heat transfer rate, of the unequal louver pitch louvered fin heat exchanger was delayed than that of the equal louver pitch louvered fin heat exchanger. The total heat transfer of unequal louver pitch louvered fin heat exchanger increased at 18% than that of equal louver pitch louvered fin heat exchanger and the pressure drop of the unequal louver pitch louvered fin heat exchanger decreased at 7% than that of equal louver pitch louver fin heat exchanger??? ????????? 2013?????? ??????(?????????????????????)??? ???????????? ????????????????????? ????????? ?????? ????????? ?????????(No. 2013R1A2A2A01067816)