Two-Phase Flow Regime Modeling and Pressure Drop Behavior

A unique horizontal two-phase flow facility has been fabricated in an effort to understand the dynamics of two-phase flow in small pipes. The fluid chosen for study is the low pressure refrigerant R-123. In this work, two-phase pressure drop data were obtained for two-phase flow of refrigerant R-123 in a 17.0 mm inner diameter tube over a wide range of quality, from .015–1, and mass fluxes that were varied from 50 kg m⁻² s⁻¹ to 550 kg m⁻² s⁻¹. These data have been compared, as a whole and by regime, against four frequently-used two-phase frictional pressure drop prediction correlations. Flow regimes were visualized using a quartz tube at the end of the test section over this wide range of conditions, which ranged from stratified to annular flow. Each condition was mapped on the Mandhane, Taitel-Dukler, and Kattan-Favrat-Thome flow regime maps in an attempt to understand the applicability of each. Some discrepancies exist between the current data and the published flow maps, and recommendations are made based on these observations. The pressure drop data appear to be dependent upon the flow regime, suggesting that an entire set of correlations is necessary based upon flow regime for accurate prediction of pressure drop.