Two-phase two-component interface drag coefficients in separated phase flows

This work examines the behavior of the interface friction factor or drag coefficient as a means for extending the modeling of separated two-phase flows through the separate consideration of each phase. The model development of this work builds primarily upon the work of Carofano & McManus (1969), Wallis (1970) and Smith (1968). A one-dimensional flow model was developed for the case of vertical upward annular fiow of an air-water mixture with droplet entrainment. The model was developed for the investigation of accelerating flows in a nozzle but is utilized in this study for the investigation of momentum transport occurring in non-accelerating flows. This study presents experimental data showing the behaviour of the flow pressure drop occurring at various flow qualities and gas velocities. Also presented are empirical results for values of the air-water interface drag coefficient as a function of flow quality and gas core Reynolds number. The drag coefficient variation is compared to a previous correlation developed by Wallis 1969).