关键词: 自然工质R290, 管内, 凝结, 两相流, 换热特性

Abstract: A model for calculating condensation heat transfer of natural refrigerant R290 inside a tube is selected by analyzing and comparing the available correlations.The flow pattern of two-phase flow of natural refrigerant R290 condensation process inside the tube is obtained.The transition of mass velocity from stratified flow to stratified-wavy flow,from stratified-wavy flow to annular and intermittent flow,from annular and intermittent flow to mist flow,and from mist flow to bubbly flow as vapor quality changes are determined.Under the same condition,the experimental and predicted values of R290 condensation heat transfer coefficients increase with the increase of vapor quality,and their difference is not significant.The condensation heat transfer coefficients of R290 and R22 increase gradually with the increase of vapor quality,the condensation heat transfer coefficient of R290 is higher than that of R22,and their difference increases with the increase of vapor quality,so it is concluded that natural refrigerant R290 has good condensation heat transfer characteristic.

Key words: natural refrigerant R290, inside tube, condensation, two-phase flow, heat transfer characteristic