▎ 摘　　要

Plate heat exchangers (PHEs) serve the purpose of enhancing heat transfer, which is important for many terrestrial and industrial applications. Since previous studies revealed that using nanofluids as the working fluid provides a remarkable augmentation in heat transfer, using them in heat exchangers is getting widespread in terms of application and research. The aim of the present study is to prove that utilization of CFD tools is an accurate method of simulating plate heat exchangers, and also, to predict the flow and heat transfer characteristics of a plate heat exchanger using the graphene nanofluid as the working fluid for various outlet temperatures and mass flow rates. This study compares the effect of working fluid, outlet temperature, and mass flow rate on heat transfer rate, Nusselt number, and effectiveness. The numerical results are found to be in good agreement with the experimental results, which validates the accuracy of the performed analyses. Considering all the flow rates and outlet temperatures for both working fluids, the results revealed that with the usage of the graphene nanofluid, the Nusselt number has increased by 15.3% and the heat transfer rate has improved by 2.73% on the average. When the results of the cold and hot fluid loops are investigated separately, it is seen that the graphene nanofluid provided an increment in both circuits, with a better enhancement for the cold loop. It has been deduced that the graphene nanofluid provides a significant improvement in the amount of heat transfer with respect to water, for each mass flow rate and outlet temperature.