TY - GEN

T1 - Limitations of "marching algorithms" in the analysis of multiphase flow in pipelines

AU - Ayala, Luis F.

AU - Alp, Doruk

PY - 2007/12/20

Y1 - 2007/12/20

N2 - Marching algorithms are the rule rather than the exception in the determination of pressure distribution in long multiphase-flow pipes, both for the case of pipelines and wellbores. This type of computation protocol is the basis for most two-phase-flow software and it is presented by textbooks as the standard technique used in steady state two-phase analysis. Marching algorithms acknowledge the fact that the rate of change of common fluid flow parameters (such as pressure, temperature, and phase velocities) are not constant but vary along the pipe axis while performing the integration of the governing equations by dividing the entire length into small pipe segments. In this algorithm, governing equations are solved for small single sections of pipe at a time, and the calculated outlet conditions for the particular segment and then propagated to the next segment as its prescribed inlet condition. Calculation continues in a "marching" fashion until the entire length of the pipe has been integrated. In this work, several examples are shown where this procedure cannot longer accurately represent the physics of the flow. The implications related to the use of this common technique are studied, highlighting its lack of compliance with the actual physics of the flow for selected examples. This paper concludes by suggesting remedies to these problems, supported by results, showing considerable improvement in fulfilling the actual constrains imposed by the set of simultaneous fluid dynamic continuum equations governing the flow.

AB - Marching algorithms are the rule rather than the exception in the determination of pressure distribution in long multiphase-flow pipes, both for the case of pipelines and wellbores. This type of computation protocol is the basis for most two-phase-flow software and it is presented by textbooks as the standard technique used in steady state two-phase analysis. Marching algorithms acknowledge the fact that the rate of change of common fluid flow parameters (such as pressure, temperature, and phase velocities) are not constant but vary along the pipe axis while performing the integration of the governing equations by dividing the entire length into small pipe segments. In this algorithm, governing equations are solved for small single sections of pipe at a time, and the calculated outlet conditions for the particular segment and then propagated to the next segment as its prescribed inlet condition. Calculation continues in a "marching" fashion until the entire length of the pipe has been integrated. In this work, several examples are shown where this procedure cannot longer accurately represent the physics of the flow. The implications related to the use of this common technique are studied, highlighting its lack of compliance with the actual physics of the flow for selected examples. This paper concludes by suggesting remedies to these problems, supported by results, showing considerable improvement in fulfilling the actual constrains imposed by the set of simultaneous fluid dynamic continuum equations governing the flow.

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U2 - 10.1115/OMAE2007-29311

DO - 10.1115/OMAE2007-29311

M3 - Conference contribution

AN - SCOPUS:37149049613

SN - 0791842681

SN - 9780791842683

T3 - Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE

SP - 709

EP - 717

BT - Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering 2007, OMAE2007

T2 - 26th International Conference on Offshore Mechanics and Arctic Engineering 2007, OMAE2007

Y2 - 10 June 2007 through 15 June 2007

ER -