Numerical simulation of heat transfer performance of R410A in condensing-superheated zone

Abstract

• Superheated condensation is a combination of convection and phase transition. • The film is thinner at higher mass flow rates in the condensing-superheated zone. • High mass flow rate enhances heat transfer in superheated condensation zone. • This study explains the heat transfer mechanism in the condensing-superheated zone. The heat transfer process in the condenser is often divided into superheated, two-phase and subcooled zone. But the three-zone model has discontinuities of the heat transfer coefficient between single phase and two-phase regions. This study applies a computational fluid dynamics (CFD) study on the two phase flow and the heat transfer characteristics in the condensing-superheated zone. The condensation process of R410A ( T sat =44.59 °C) in a horizontal pipe ( D i =6.1 mm) is simulated by using VOF (volume of fluid) model. The formation and the development of the condensation film are detailed analyzed. The heat transfer mechanism in the condensing-superheated zone includes both the single-phase convection and the phase transition. The heat transfer coefficient in the superheated condensation area increases from the single-phase convection to the saturated condensation. Combined with the development of liquid film morphology, this study is helpful for understanding the flow and heat transfer mechanism in the condensing-superheated zone.