A Numerical Study on Heat Transfer of R410A during Flow Boiling

Abstract

A numerical simulation was conducted to study the heat transfer characteristics of R410A during flow boiling at low vapor quality in a horizontal tube. The thermal phase change model in Fluent was used to describe the flow boiling phenomenon and validated by the experimental data from the existing literature. The effects of mass flux and heat flux on the flow boiling heat transfer were clarified. The results showed that the heat transfer coefficient increased with the increase of mass flux while decreased with the increase of vapor quality due to the interaction of nucleate boiling and fluid convection. However, the effect of heat flux was slight on the flow boiling heat transfer coefficient indicating that the flow boiling was governed mainly by the fluid convection. The simulation results were compared with the predictive values of four well-known heat transfer correlations. The Kandlikar and Jung’s correlations underpredicted the heat transfer coefficient. The Sun’s correlation showed the best agreement with a mean absolute deviation mostly less than ±15% for heat transfer. This study makes up the gap of numerical simulation on the flow boiling of R410A and these results would be useful for the understanding of flow boiling mechanism of R410A and the design and optimization of heat exchanger and the substitution of refrigerants.