Design and Analysis of Multiple Parallel-Pass Condensers

摘要

This paper describes and analyzes a novel design of multiple parallel-pass (MPP) microchannel tube condenser and its applications to automotive A/C systems.A flow distributor concept is introduced in MPP condenser in order to enable parallel flow arrangement in adjacent flow paths.Throughout analysis of two-phase flow and heat transfer processes in MPP condenser,a two-phase zone augmentation technique is developed that can be employed to enhance condensation heat transfer and reduce pressure drop.Experiments in both visualization and heat transfer performance are carried out to evaluate MPP condensers by referencing a baseline PF condenser.Visual observation by using a high-speed camera indicates that a more uniform refrigerant quality entering the next cooling pass can be achieved in MPP condenser because superheat vapor through a pass-through hole on flow distributor directly injects into the separated liquid-vapor zone in a header tube.In addition,analytical and test results show MPP condenser,being designed to enlarge two-phase condensing zone,is able to improve cooling performance as high as 9.5% while its refrigerant mass flow increases as high as 13.34% when comparing to a benchmark PF condenser.