A Study Of The Characteristic Of Two-phase Flow In Undulating Wet-gas Pipelines

Based on the one-dimensional form of the mass and momentum conservation equations for the gas and the liquid phases,a transient two-fluid model is developed to predict two phase flow in undulating pipes.A flow pattern prediction model is also integrated into the main model.The conversation equations are linearized and discretized using a finite volume method.Coefficients of the linearized equations are derived.A more accurate discretization scheme QUICK is applied.UDS method is used when treating the boundary conditions.A transient two-phase flow code is developed,based on the model mentioned above.Two loops are needed in the solution procedure.The outer loop is used to solve the momentum equations while the inner loop is for the masse conversation equations.Convergence criterions for each loop are also stated.An algorithm used to solve the linear algebraic equation set is proposed,namely BPDMA(Block Penta-diagonal Matrix Algorithm).The transient two-phase flow code is validated using available experimental data.The flow regime prediction results agree with the experimental observation well and the calculation precision meets the requirement of engineering.A multiphase flow software package is also used to simulate the mentioned laboratory experiments.Result shows that the package is a little more precise than the code in calculating flow parameters.However,the code advances in prediction flow pattern.The model is improved with BWRS equation due to the bad performance in calculating pressure.The improved code is verified to be more precise in simulating the two-phase flow in undulating pipes.The results calculated by the code match the measured data well.At last,using the improved code,nearly 40 conditions are studied to explore the influences of five parameters on the gas-liquid two-phase flow in undulating pipe,namely the inclined angle,the gas-liquid rate,the flow rate,the diameter and the outlet pressure.