Linear stability analysis for severe slugging in air-water systems considering different mitigation mechanisms

This work presents a numerical study of the effects of mechanisms such as gas injection, choking and different boundary conditions on the stability of the stationary state for two-phase flows in vertical and catenary pipeline-riser systems. Numerical linear stability analysis is performed to a suitable mathematical model for the two-phase flows in a pipeline-riser system. The mathematical model considers the continuity equations for the liquid and gas phases and a simplified momentum equation for the mixture, neglecting inertia (NPW - no pressure wave model). A drift flux correlation, evaluated in local conditions, is utilized as a closure law. Gas injection and a choke valve are added, respectively, at the riser bottom and top. The extended model is applied to air-water pipeline-riser systems reported in the literature. Numerical linear stability analysis results are compared with experimental and numerical results reported in the literature with excellent agreement.