Study on Heat Transfer and Pressure Drop Characteristics in Fin Micro Channels of Hybrid Heat Exchangers

The supercritical carbon dioxide (S-CO2) power generation system has the characteristics of compact structure and high efficiency, and can be applied to the waste heat recovery of ships. The hybrid heat exchanger with printed circuit heat exchanger (PCHE) and formed plate heat exchanger (FPHE) can meet the heat exchange requirements of S-CO2 and flue gas. In order to study the fin micro channels performance of hybrid heat exchangers, a simulation model of the fin micro channels of the hybrid heat exchanger was established. The effects of fin thickness, inlet temperatures and inlet mass flow rates on heat transfer and pressure drop characteristics were studied. The results show that the fin thicknesses of 0.2 mm 0.3 mm and 0.4 mm have little effect on heat transfer and pressure drop characteristics. When the inlet temperature increases from 663K to 723K, the total heat transfer rate increases, and the heat transfer coefficient and pressure drop remain substantially unchanged. When the mass flow rate of the inlet increases from 0.0007 kg/s to 0.0013 kg/s, the total heat exchange rate, total heat transfer coefficient and pressure drop increase. The research work in this paper can provide theoretical guidance for the design of the fin micro channels of the hybrid microchannel heat exchanger.