Numerical simulation of the start-up of Bingham fluid flows in pipelines

This paper describes a mathematical model used to simulate the restart of an axial, compressible and transient flow of a Bingham fluid in circular or annular pipes. The model is based on the mass and momentum conservation equations plus a state equation that relates pressure to density. The viscous effect is modeled by employing a friction factor approach. The governing equations are discretized by using the finite volume method with a first-order upwind scheme, and the resulting non-linear algebraic equations are then solved iteratively. The model results were corroborated by an analytical solution for Newtonian flows. Additionally, the results were also in reasonable agreement with results reported in the literature. We also conducted sensitivity analyses with respect to Reynolds number, aspect ratio, gravity and the non-linear advective terms of the governing equations. (C) 2010 Elsevier B.V. All rights reserved.