Research On The Flow Characteristics Of Oil-water Annular Flow In Straight Pipe Under Vibration Condition

With the continuous acceleration of industrial development,the consumption rate of petroleum resources has also accelerated,and the abundant heavy oil as an important alternative resource has gradually attracted everyone’s attention.The high viscosity of heavy oil brings inconvenience to transportation.As an efficient and energy-saving oil transportation technology,transporting heavy oil through annular flow has been increasingly favored by scholars.At present,the proven heavy oil is mainly distributed under the ocean.During transportation,pipelines are inevitably affected by ocean surges,leading to instability of the annular flow structure and significantly reducing oil transportation efficiency.Through the analysis of the current research status,it was found that there is relatively little research on the oil water annular flow under vibration conditions,which is insufficient to support the practical needs of engineering.Therefore,this project focuses on studying the flow characteristics of annular flow in straight pipes under different vibration conditions,exploring the effects of vibration amplitude and frequency on its flow characteristics,and the mechanism of action on water ring stability.The main research content of the paper includes:(1)Build an oil-water annular flow experimental system for experimental research,and the experimental results show that the flow pattern of the experimental system is consistent with previous research.Construct and mesh physical models with the same geometric parameters,construct straight pipes,and unstructured mesh them.Use numerical simulation software to set the model,including the selection of calculation methods,definition of boundary conditions,and completion of two-phase flow simulation calculations.The good fit between the calculation results and experimental results proves the feasibility of applying the numerical calculation method selected in this paper to the research of this topic.(2)Using a model to simulate the oil-water two-phase flow in a horizontal pipe under vibration conditions,the flow patterns under different operating conditions were obtained through the results.Quantitative analysis was conducted on the flow boundary,and a positive correlation was found between the inlet flow velocity and the stable frequency of annular loss.The relationship between the degree of oil phase eccentricity and vibration parameters was obtained.Analyzed the pressure drop of different pipe sections,explored the effects of vibration and flow parameters on oil-water two-phase flow,and explored the mechanism of action between different pipeline motion stages and flow conditions.(3)Using a model to simulate the oil-water two-phase flow in a vertical pipe under vibration conditions,the flow patterns under different operating conditions were obtained through the results,and the flow boundary was quantitatively analyzed.Analyzed the effects of different vibration and flow parameters on oil-water two-phase flow,explored the stable two-phase loss conditions under different inlet flow rates,and explored the periodic variation of pressure drop in different pipe sections.The above research conclusions further improve the simulation research of oil-water two-phase flow in straight pipes under vibration conditions,providing a reference basis for the problem of water ring transportation of heavy oil,and providing reference value for the practical application of oil-water two-phase flow under vibration conditions.