Influence of vibration on transient flow characteristics of gas-liquid two-phase flow in inclined pipes

Abstract

As an advanced method of transportation globally, pipelines play a significant role in the energy sector of many nations. Given the rapid development of offshore oil and gas engineering, it is critical for researchers to focus on the dynamics of pipelines and the flow characteristics of internal fluids under oceanic conditions. In this paper, a gas-liquid two-phase flow numerical model was developed to simulate transient flow characteristics in an inclined pipe at different vibration conditions based on CFD dynamic mesh technology. The CFD model was verified against experimental data, showing that the numerical simulation predicts average pressure drop within 10 % of experimental data. Parametric studies were conducted based on the CFD analysis, including vibration direction (horizontal, vertical, and inclined), vibration amplitude (0.5D∼1.5D) and flow velocities (jsg=0.5∼1.0m/s, jsl=0.1∼1.0m/s). Meanwhile, the downhill and uphill sections of the pipeline were considered. The results indicated that inclined vibration had the most substantial impact on flow, followed by horizontal vibration and vertical vibration. The changes of average liquid holdup were closely related to flow pattern under vibration conditions. These vibration conditions significantly effected pressure fluctuations and secondary flow. The impact of vibration on transient flow heightened with increased vibration amplitude. In addition, transient flow behaviors showed periodicity, and the evolution period was consistent with the vibration period. These findings are helpful to understand the transient flow behaviors in inclined pipe under vibration conditions.