Simulation of Transient Two-Phase Flow in Pipelines

Abstract

The laws of conservation of mass and linear momentum were applied to a two-phase mixture to formulate a mathematical model which simulates isothermal, transient two-phase flow of gas and liquid in a pipeline. Liquid holdup and friction factors were incorporated via existing empirical correlations, and the black oil method was used to describe interphase mass transfer. Implicit finite difference analogues were derived for the nonlinear set of partial differential equations which constituted the basis of the model. The system of difference equations was solved using a sequential solution algorithm implementing a Newton-Raphson iterative procedure. The numerical model formulated was used to predict the performance of an existing wet gas pipeline to establish the validity of the model. Example simulation runs were used to provide insights into the nature of transient two-phase flow.