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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

An Experimental Investigation of Two-phase Refrigerant R-410A Flow Distribution in Plate Heat Exchangers

Get access (open in a dialog) DOI: 10.1615/IHTC15.fbl.009604
pages 2559-2570

Resumo

A plate heat exchanger (PHE) is made by combing several corrugated stainless plates. Working fluids pass through the channels between adjacent plates and exchange heat through the plate. It is commonly used as evaporators in air-condition and refrigeration systems because of their compactness and high heat transfer performance. For two-phase refrigerant flow through the header of a large plates number PHE, because the inertia of the liquid flow is much higher than that of vapor flow, most of the liquid will flow through the passages far away from the inlet port and caused the flow mal-distribution. Recently, a so-called inlet distributor has been designed for reducing this kind of flow mal-distribution. A small hole was used to restrict the amount of liquid flow through each passage. However, this design caused another mal-distribution of flow inside each passage between the plates. This study provides an experimental observation of evaporating two-phase refrigerant 410A flow distribution in a plate heat exchanger by the method of Infra-Red Thermography. The test section was made by brazing four stainless steel chevron corrugate plates to form a three flow passages plate heat exchanger. Refrigerant flowed through the central passage of the plate heat exchanger upwardly while water flowed through the outer two side flow passages downwardly to form a counter flow. Two-phase refrigerant R-410A with vapor quality of 0.2 flowed into the heat exchanger through a small hole at various directions as the inlet distributors. An Infra-Red Thermography was installed in front of the plate to measure the plate surface temperature distribution. Since the liquid refrigerant evaporated and absorbed heat from the water side, the liquid refrigerant flow distribution can derived from the water temperature distribution. The experiment results show that the liquid refrigerant flow uniformity in a passage can be significantly improved by appropriate design of the inlet hole direction. The optimum direction of the distributor hole changes with flow rate. For lower Re (= 500), distributor hole at the direction reversed to the main flow direction provides the most uniform liquid flow distribution. However, for higher Re (= 1,500), distributor hole at the direction perpendicular to the main flow direction is the best.