Heat transfer correlation of the falling film evaporation on a single horizontal smooth tube

The falling film heat transfer of R134a outside a single horizontal smooth tube is experimentally investigated, and the effects of the tube diameter, saturation temperature, film flow rate and heat flux are studied. A threshold Reynolds number is proposed to delineate the test data into full wetting and partial dryout regimes. New correlations based on the present data and some data in literature are fitted for both regimes. The correlation for partial dryout regime fits 91% of the 153 data within +/- 20%, and the correlation for full wetting regime fits 94% of the 205 data within +/- 20%. The correlations have also been compared with previous measured data of other refrigerants available in literature. It is found that the predictions for partial dryout regime agree with most of the previous data with a deviation of +/- 30%. (C) 2016 Elsevier Ltd. All rights reserved.