Saturated flow boiling of FC-72 in 1 mm diameter tube

Due to the important role of microscale heat transfer, an analysis of the heat transfer coefficient for a 1 mm inner diameter tube, with FC-72 as working fluid, has been performed. The study is aimed to identify the best correlation or model to predict the available experimental database. A comparison of several models and correlations, available in the literature for micro- and macroscale, has been performed, focusing the present preliminary analysis to the saturated boiling conditions. Experimental data have been provided by ENEA through the facility BO.E.MI.A. (BOiling Experiments in MIcrochannel Apparatus), in the pressure range from 3 to 5 bar, with a mass flux from 800 to 1200 kg/m2s and thermal fluxes from 1.6 to 181 KW/m2. The best results, in this preliminary analysis of the saturated boiling points, were obtained for microscale correlations of Li and Wu, with more than 91% of data within ± 30% error and a mean absolute percent error (MAPE) of 13.4%. Among the macroscale correlations only the Chen correlation provides good results, but with a lower agreement with the experimental data. Theoretical models are very promising but need further works to find the appropriate parameters valid for the specific fluid. A more detailed analysis including subcooling conditions will be performed in a future work.