Transient simulation of 2D and 3D stratified and intermittent two‐phase flows. Part I: Theory

Abstract

SUMMARYStratified and intermittent stratified-bubble (slug)

Preconditioned Krylov subspace methods used in solving two-dimensional transient two-phase flows

“…To close the equation system these new terms must be modelled. The closure of the two-fluid model used in this work was outlined by Moe and Bendiksen [10]. Here we only state the main assumptions and present the resulting equations.…”

“…With this correction, a robust non-iterative scheme is obtained. In previous works [10,13], the algebraic equation system resulting from the discretization of the pressure and momentum equations as well as for the mass equations, were solved with a Gaussian band solver. In the present work, the pressure -momentum algebraic equations are also solved with preconditioned Krylov subspace iterative algorithms [14].…”

“…The fluids can be separated (two continuous phases) and/or distributed (bubbles in liquid, droplets in gas). The model has been used [10,13] to simulate the broken dam problem, collapse of a liquid column, separation of mixed gas and liquid, propagation of a single Taylor bubble in horizontal and inclined channels and the initiation of slugs in upward inclined channels. By specifying a zero fraction of one of the fluids, single-phase flow cases have been simulated as well.…”

“…In the numerical solution procedure implemented by Moe and Bendiksen [10], a pressure equation is solved simultaneously with the momentum equations for the two phases. Mass equations for each phase are solved in a separate step.…”

“…On the other hand, more coupled solution methods demand good algebraic equation solvers. In this work, we investigate the behaviour of preconditioned Krylov subspace methods for solving algebraic equations systems resulting from a coupled solution strategy implemented by Moe and Bendiksen [10] for the two-fluid model [11,12].…”