Study on laminar film-wise condensation for vapor flow in an inclined small/mini-diameter tube

The correlating factors for flow condensation in small/mini-diameter tubes are analyzed by energy consideration. Based on the in-situ interface config uration, an analytical model is proposed for predicting the heat transfer c haracteristics. Both analytical and experimental results show that gravity has a decreasing effect on flow condensation in small/mini tubes. The incli nation angle affects condensation heat transfer mainly by distributing grav ity in stratifying the fluids and thinning the liquid film. In larger tubes , the former may become the main reason for heat transfer enhancement, espe cially in high vapor quality zone and at low inlet vapor Reynolds number. C omparison with the experimental data indicates that the proposed analytical model has a good capability for predicting flow condensation heat transfer in small/mini-diameter tubes. (C) 2000 Elsevier Science Ltd. All rights re served.