Two-phase flow distribution in dual-compartment microchannel heat exchanger header

With the inherent flow maldistribution problem within the microchannel heat exchanger header, which degrades the heat transfer performance, new microchannel heat exchanger header was designed and tested to improve this flow distribution performance, specifically for R410A. It features dual-compartment made of multiple layers consisting of the main section, baffle and hole seat, and rear section. Twenty flat tubes containing microchannels were inserted at 50% protrusion. Experiments and visualizations were conducted at 50, 100, and 200 kg·h^-1 of mass flow rate (equivalent mass flux of 220.5, 441, and 882 kg·m^-2s^-1), which were at partial to full loading capacity. Inlet vapor quality was fixed at 0.2 and evaporating temperature at 15 ºC, for evaporator application of air-conditioning system. Considering the same microchannel element, flow distribution enhancement was achieved when compared to the conventional header data. Liquid flow distribution was improved by around 65% at part-load conditions based on the relative standard deviation.