A model for pressure loss, film thickness, and entrained fraction for gas–liquid annular flow

• Published in: The International journal of heat and fluid flow 2011-06, Vol.32 (3), p.730-739
• Main Authors: Schubring, D., Shedd, T.A.
• Format: Article
• Language: English
• Subjects: Annular flow; Computational fluid dynamics; Disturbance wave; Disturbances; Entrainment; Errors; Exact sciences and technology; Film thickness; Flow rate; Fluid dynamics; Fundamental areas of phenomenology (including applications); Multiphase and particle-laden flows; Nonhomogeneous flows; Physics; Pressure gradient; Pressure gradients; Two-phase flow
• ISSN: 0142-727X; 1879-2278
• DOI: 10.1016/j.ijheatfluidflow.2011.02.010

A two-component (air–water) annular flow model is presented requiring only flow rates, absolute pressure, temperature, and tube diameter. Film thicknesses (base film and wave height) are calculated from a critical film thickness model. Modeled pressure gradient is weighted by wave intermittency to compute average pressure gradient. Film flow rate and wave velocity are estimated using the universal velocity profile in the waves and a piecewise linear profile in the base film. For vertical flow, mean absolute errors for film thickness, wave velocity, and pressure gradient are 9%, 9%, and 19%, respectively. In horizontal flow, mean absolute errors for pressure gradient, base film thickness, and disturbance wave velocity are 17%, 10%, and 14%, respectively, on par with those from single-behavior models that require additional film thickness or other data as inputs.