Numerical Modelling of Gas-Liquid Slug Flow Regime with a Conservative Two-Fluid Model Using the Shock Capturing Method

An approach for simulating the initiation of slugs in horizontal pipes is proposed in this research. An analogy is established between the algorithms for solving single-phase problems with discontinuity (Riemann problems) and two-phase slug flow (having a discontinuity in the interface), employing a unique algorithm to solve the conservation equations. Numerical solutions to equations for two-fluid dynamics with transient behavior are obtained by applying a group of conservative shock-capturing techniques. The benefit of utilizing this approach is that the creation of slugs can be computed directly according to the solutions of the differential equations governing the flow field; hence, the location of the interface can be found instantly and without simulation, and the slug regime can be captured automatically. Furthermore, the slug can be captured with low computational cost using a conservative shock-capturing method compared to methods like finite volume. It is demonstrated that the two-fluid model may describe the development of instabilities in stratified flow that give rise to slugs when the mathematical character of the model is hyperbolic. Additionally, the results of numerical modeling and experimental analysis coincide well with the location of slug start. This approach can forecast the flow pattern map and the change from stratified to wavy, and then eventually, slug flow.