Heat transfer enhancement of modified flat plate heat exchanger

Abstract

Flat plate heat exchanger (FPHE) can tolerate more mass flow rate, significantly yield lesser pressure drop, and it is easier for manufacturing than the corrugated plate heat exchanger (CPHE). However, the overall thermal performance of FPHE is poor due to its low heat transfer rate. Therefore, the aim of the current study is to improve the thermal performance of the existing conventional FPHE (FPHEC). Thus, two newly developed modified FPHEs are introduced (FPHEm1 and FPHEm2). A computational fluid dynamics (CFD) technique is applied to numerically test the performance of the heat exchangers (HEs). Moreover, experiments are carried out to confirm the validity of the numerical results obtained in this study. The performance of FPHEm2 significantly outperforms that of FPHEC and FPHEm1. Hence, the results of FPHEm2 are compared with those of the conventional corrugated plate heat exchanger (CPHEC). Data of Nusselt number (Nu), fanning friction factor (f), turbulence intensity, JF factor, severity of temperature gradient of the plate (ΔTp), and average temperature through the plate (Tp,avg) are employed to quantify the best performance among all four HEs. The numerical results show that FPHEm2 has the best temperature uniformity and average temperature (the lowest values), and it has the highest Nu, JF, and turbulence intensity among all four HEs. Also, the f data of the FPHEm2 are 18.7% to 33.2% lower than those of the CPHEC. Thus, FPHEm2 could be a probable replacement of its counterparts of both FPHEC and CPHEC. Critical Reynolds numbers (Recr) of FPHEm2, heat transfer correlations and the flow distribution along with other details have been analysed numerically.