Two-phase refrigerant distribution in a parallel flow minichannel heat exchanger having lower combining/dividing header

R-410A distribution in a two pass evaporator with lower horizontal combining-dividing header was investigated. Tubes were heated to yield a test section outlet superheat of 5 degrees C with inlet quality of 0.2. The number of tubes was ten for the inlet pass and 12 or 14 for the outlet pass. For each case, mass flux was varied from 73 to 143 kg/m(2) s. In the combining/dividing header, two-phase mixture out of the inlet pass is first merged and then redistributed to the outlet pass. More liquid is forced downstream as mass flux or quality increases Effect of insertion device in the inlet header was also investigated. Efforts were made to develop correlations to predict the liquid or gas distribution in a header with limited success. Header pressure drop data are also provided.