ADIABATIC CAPILLARY-TUBE EXPANSION DEVICES - A COMPARISON OF THE HOMOGENEOUS FLOW AND THE SEPARATED FLOW MODELS

Literature shows that the homogeneous flow assumption has been commonl y used in most of the adiabatic capillary tube modelling studies. The slip effect between the two phases was often not considered in this sm all diameter (about 1 mm) capillary tube. Due to the lack of experimen tal information of the slip ratio in the flow within the capillary tub e, the more comprehensive separated two-phase how model was not freque ntly used in theoretical studies. This paper attempts to exploit the p ossibility of the separated flow model. Comparisons of the predicted r esults between the homogeneous and the separated flow models are prese nted, together with experimental results from previous workers. The re sults show that the separated flow model using the Miropolskiy's slip ratio combined with Lin's frictional pressure-gradient correlations gi ves a better prediction compared to the homogeneous flow model. Copyri ght (C) 1996 Elsevier Science Ltd