Condensation heat transfer performance and pressure drop of R513A in horizontal microfin tubes
In order to investigate the condensation heat transfer performance and flow characteristics of R513A in microfin tubes,the condensation heat transfer coefficient and pressure drop of R513A in smooth and microfin tubes with outer diameters of 12.7 mm and 9.52 mm were analyzed experimentally.The experimental conditions were mass fluxes 50-270 kg/(m2·s)and condensation temperatures 33,35,38,40 ℃.The results show that the R513A condensation heat transfer coefficient in the smooth tube is 18.8％-25.5％lower than that of R134a,and the deviation is-5.5％-0.8％in the microfin tube.The condensation heat transfer performance of R513A is enhanced more significantly than that of R134a in the microfin tube.The pressure drop of R513A is 5.6％-17.8％lower than that of R134a.When the tube diameter decreases,the condensation heat transfer coefficient and pressure drop of R513A both increase.The Oliver correlation has the highest prediction accuracy for the tested microfin tube,and the average deviation is about 14.56％.For the prediction of pressure drop,calculated results of selected correlations have large errors with some of the experimental data.The newly fitted correlation well predicts the pressure drop of R513A condensing in the microfin tube,with 95.32％of the data points within 30％error line.
R513Acondensationmicrofin tubeheat transfer coefficientpressure drop correlation
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