In order to know the heat transfer enhancement mechanism of liquid-vapor separation condenser

the theoretical design method of tube pass in the condenser was investigated. The Cavallini heat transfer model was chosen to calculate the in-tube mean heat transfer coefficient by the flow pattern estimated according to the refrigerant mass flow rate and average quality in each tube. The two-phase pressure drop model of Cavallini and the single-phase pressure drop model of Darcy-Weisbach were also applied to calculate the pressure drop of condensation zone and sub-cooling zone

respectively. In addition

a case with three schemes was designed here to evaluate the mean heat transfer coefficient and pressure drop

and its thermodynamic performance was evaluated with the Penalty Factor. The result indicated that different schemes of tube pass resulted in the variable refrigerant mass flux rate in tubes

and the more even refrigerant distribution in the condenser

the better its thermodynamic performance. The Penalty Factors of best one of three liquid-vapor separation condensers is about 48.5%~54.1% less than the serpentine condenser with the same heat transfer area at mass velocity of 1200~1500kg/(m2.s). That is to say

the thermal and dynamic characteristics of the liquid-vapor separation condensers with good design scheme are superior to the serpentine condenser at the same conditions.