CO{sub}2 FLOW BOILING HEAT TRANSFER IN HORIZONTAL TUBES, PART I: FLOW REGIME AND PREDICTION OF DRYOUT

摘要

The possible flow patterns of CO{sub}2 flow boiling in horizontal tubes are studied based on the analysis of the unique properties of CO{sub}2 and current flow pattern maps found in the literature. Annular flow is found to be the predominant flow pattern for normal operating conditions. The mechanisms to sustain annular flow are examined and it is concluded that liquid entrainment and deposition are the most important mechanisms for CO{sub}2 and that the occurrence of dryout is an important phenomenon in annular CO{sub}2 flow. A model to predict the onset of dryout and the location of complete dryout for the CO{sub}2 flow boiling in horizontal tubes is described and evaluated.