Update on advances in flow pattern based two-phase heat transfer models

The flow pattern, simplified flow structure based evaporation model of Kattan et al. [J. Heat Transfer 120 (1998) 140; J. Heat Transfer 120 (1998) 148; J. Heat Transfer 120 (1998) 156] has been updated several times since its original publication and also generalized to intube condensation. The current status of our work on this heat transfer prediction model and flow pattern map is described here, covering the following topics: the onset of nucleate boiling, elimination of iterative calculations, evaporation of CO2 up to pressures as high as 64 bars for tube diameters from 0.9 to 10.0 mm, convective condensation inside horizontal tubes, and the recent experimental verification of the drift flux void fraction model used by the flow pattern map and heat transfer model.