Two-phase refrigerant distribution in an intermediate header of a parallel flow minichannel heat exchanger

• Two-phase distribution in an intermediate header is investigated.
• Insertion device does not affect the flow distribution in the second pass.
• Correlations are developed for liquid or gas ratio taken off by downstream channel.
• Header pressure drops are obtained from the calculated and measured pressure drops.

Refrigerant R-410A distribution in a two pass evaporator with intermediate header was investigated. The number of tubes was 10 for the first pass and 12 for the second pass. Tests were conducted for the mass flux from 73 to 143 kg m−2 s−1, quality from 0.4 to 0.6. In the intermediate header, two-phase mixture out of the first pass is merged and then re-distributed to the second pass. More liquid is forced downstream as mass flux or quality increases yielding better flow distribution. 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.