Pressure drop and heat transfer for flow-boiling of water in small-diameter tubes

Abstract

Pressure drop and heat transfer for flow-boiling of water in small-diameter tubes under atmospheric pressure were discussed. The results of experiments were compared with those of several existing correlations and models. The experiments were carried out using atmospheric-pressure water in tubes with inner diameter D ranging from 2.0 to 6.0 mm, heated length L from 4.0 to 680.0 mm, inlet water subcooling ΔTin from 70 to 90 K, and mass velocity G from 100 to 10 170 kg/(m2s). The highest heat flux q attained was 33 MW/m2. Interesting phenomena were observed in small-diameter tubes with a very short heated length. The most suitable correlations for predicting the pressure drop and heat transfer in small-diameter tubes were also discussed.