Flow capacity of the capillary copper tube as its figure of merit

Abstract

The use of capillary copper tube is popular for manufacturing of gauges and evaporators of refrigeration units. Its main feature is a small inner diameter (no more than 0.9 mm), which makes it difficult to measure it along the whole length of the tube, thus, indirect test methods are used for its determination. Main problem in manufacturing of quality tubes is providing the necessary flow capacity. This article features these under-investigated issues by determining correlation between technological parameters and figures of merit of the capillary copper tubes. Specifically, it was found how flow capacity changes by the influence of such parameters as heat treatment (annealing), tube channel diameter and length of the treated product. © 2020 Published under licence by IOP Publishing Ltd.