Experimental study of condensation heat transfer for R141b in intermittent flow regime within a smooth horizontal tube

Abstract

This study investigates condensation of R141b in an 8 mm ID horizontal smooth tube. Condensation of R141b is conducted at an average saturation temperature of 40°C with mass fluxes ranging from 40 to 400 kg m−2 s−1. The plant runs with low vapor quality of refrigerant where intermittent flow is expected to be the dominant flow regime. Visualization images presented for intermittent flow regime. Observation results compared with four types of flow regime map and a modified version of El Hajal-Thome map is presented. Condensation heat transfer coefficient in intermittent zone is evaluated. Comparison between the available experimental data and the values predicted by the most popular and current correlations for condensation heat transfer in horizontal tubes are reported. Finally, a new correlation is proposed to predict condensation heat transfer coefficient within intermittent region.