Experimental investigation of distributor configuration on flow maldistribution in plate-fin heat exchangers

Plate-fin heat exchangers are a class of compact heat exchangers that are extensively applied in industry. The distributor configuration used to distribute fluid flow among the channels of a plate-fin heat exchanger can significantly influence the thermal performance of such heat exchangers. In this work, various distributor configurations were used with a plate-fin heat exchanger under different operating conditions to assess the resultant change in its flow distribution and thermal performance. It was found that certain design features of the distributor caused severe flow maldistribution and that the flow Reynolds number based on the average flow velocity in the heat exchanger channels and the channel hydraulic diameter substantially affected the flow distribution, which in turn significantly influenced the heat exchanger's thermal performance. An improved distributor design, with a complementary fluid cavity was built and tested in this work. The experimental results show that improved distributors are very effective in improving the flow distribution in heat exchangers, and consequently, their thermal performance. The most uniform flow distribution and heat transfer were obtained, when the improved distributor configuration parameter, which represents the ratio of the height of the complementary cavity (h) to the total distributor height (H), is 0.2. By incorporating this distributor at the inlet of the plate-fin heat exchanger, the flow and temperature non-uniformity in the same were reduced to 57.4% and 13.7% of the baseline design respectively, at the main test condition. Correlations between the flow distribution uniformity and Reynolds number for the various distributor configurations have also been provided.