| The objective of the present study was to develop a hydrodynamic model for fully-developed, annular, two-phase flows through horizontal pipes. The model is capable of describing local variations in the film thickness and local velocity profiles with respect to the radial and circumferential position within the pipe.; The study consisted of two parts: (1) development and solution of the mathematical model, the results of which are reported in the attached document, and (2) collection of experimental data on the film thickness for air-water flows in a 50.3 mm diameter horizontal pipe for Re{dollar}sb{lcub}rm g{rcub}{dollar} ranging from 47,000 to 202,000 and Re{dollar}sb1{dollar} ranging from 1,400 to 16,700. The actual collection of the experimental data was conducted jointly by the present author and by Mr. John Kitscha. Details of the experimental study are reported in (29). The experimental data from this study, along with experimental data from other investigators, was used to verify the mathematical model.; The resulting model is based on the direct solution of the local field equations using a finite difference approach. Unlike previously developed models, which involved integration of the field equations across the film boundary layer, the present model can describe the local hydrodynamic behavior as a function of radial, as well as circumferential position. The model is valid for superficial gas Reynolds numbers between 115,000 and 305,000, and for superficial liquid Reynolds numbers between 100 and 12,000. The model is valid for air-water flows as well as the flows of air and viscous liquids such as 50% glycerin. Agreement between the model and experimental data is good, with the errors between the predicted and experimental film thicknesses ranging between 5.9% and {dollar}-{dollar}29.6%. |
