Heat Transfer and Flow Characteristics of Refrigerant R134a during Boiling Inside a Plate Heat Exchanger with a Copper Foam Insert

10.14416/j.ind.tech.2024.12.003

Abstract

This article studies the effects of mass flux, vapor quality of the refrigerant, and the insertion of copper foam inside the flow channel on the heat transfer and pressure drop of refrigerant R134a during boiling in a plate heat exchanger with a copper foam insert. The tests were conducted under conditions of a saturation temperature of 15 °C, a heat flux of 20 kW/m², an average vapor quality between 0.25 and 0.87, and a mass flux between 10.8 and 32.5 kg/m²s. Copper foam with a pore density of 40 PPI and a porosity of 0.932 was used. The experimental results revealed that an increase in average vapor quality and mass flux led to an increase in the heat transfer coefficient and pressure drop. The insertion of copper foam had a significant effect on the heat transfer coefficient and pressure drop, with average increases of 21.7% and 22.0%, respectively. The thermal performance evaluation indicated that the insertion of copper foam (at mass flux = 16.2 kg/m² s) resulted in a 13.7 % increase in the thermal performance of the plate heat exchanger compared to the plate heat exchanger without the copper foam insert. This research provides a better understanding of improving the performance of the plate heat exchangers using copper foam, which can be applied to the design of high-efficiency compact plate heat exchangers in the future.