Flow condensing heat transfer of R410A inside a micro-fin tube

An experimental study of condensation heat transfer and pressure drop inside a horizontal micro-fin tubes are conducted using the azeotropic mixture refrigerant R410A as a test. This study was especially focused on influence of heat transfer area on the condensation heat transfer coefficient and pressure drop. The test sections were double tube of counter-flow type; the refrigerant was flowing condensed inside of test tube by heat exchange with cooling water flowing in the annular side. The temperature and pressure of refrigerant were measured at inlet and outlet of test section, and the temperature surface of tubes were measured. The pressure drop in the test section were directly measured by a differential pressure transducer. The heat transfer coefficient and frictional pressure gradient were calculated using the experimental data. The heat transfer coefficient and pressure drop were measured at the saturation temperature of 48 degrees C within mass fluxes of 50-380kg/ (m2s) and heat fluxes of 6-12kW/m2. The pressure drop and heat transfer coefficient characteristics of the R410A were examined and compared with those of the R22 at the same test conditions. The experiment results are compared with the existing heat transfer coefficient correlations, and a new correlation is developed with good prediction. (C) 2017 The Authors. Published by Elsevier Ltd.