One drawback to the implementation of compact heat exchangers is nonuniform distribution of liquid in the manifold. There is a significant opportunity to improve the performance of this type of compact heat exchanger by improving the distribution of refrigerant liquid among the heat exchanger tubes.

In order to do that, an effective means of measuring the liquid distribution among the heat exchanger tubes needs to be developed. This paper presents the features of an apparatus that uses an innovative technique to measure the liquid flow rate in each heat exchanger tube. The flow rates were measured using collection tanks mounted on load cells using a batch method. The mass balance between the overall liquid flow rate at the inlet to the test section and the sum of the individual flow rates was within 10%.T he repeatability of the apparatus, in terms of measuring the nonuniformity, ranged from –4.9% to +2.8% based on the average value of three repetitions.

This apparatus is a useful tool to quantify the effects of nonuniform distribution of liquid in the manifolds of compact heat exchangers, which, in turn, will lead to a better understanding f the causes of maldistribution and how to correct it. This will be a topic of future papers.

Units: Dual