Two-Phase Annular Flow in Pipes: Analytical Models

摘要

Analytical models describing two-phase annular flow are derived from fundamental principles. The models are developed in increasing levels of sophistication beginning with a simple one-dimensional model, proceeding to several integral techniques, and ending with a detailed derivation of a differential analysis. The general differential analysis is based on two equations: (1) the shear stress equation and (2) the shear stress - velocity gradient relationship. The physical model is divided into three regions: (1) the liquid film, (2) the interface, and (3) the gas core. Each region is analyzed separately. A 'universal' velocity profile law for the gas core is developed which appears to apply for entrainment fractions less than 40%. (Author)