Study On The Gas-liquid Two-phase Flow Numerical Simulation In Undulating Pipeline Based On VOF

With the ever-increasing demand of petroleum in China,large numbers of oil pipelines are built up and put into operation successively.Pipeline commissioning process,as a critical stage,which connects construction and daily operation,is attracting more and more attention.Direct commissioning has been more widely used because of cost advantage in recent years.However,during the process of direct commissioning,gas-liquid two-phase flow has an effect on the safety of pipeline.Therefore,this article is divided into two parts.Firstly,it introduces the study on the huge stagnant air pocket suspending in downward pipe section which lead to gas-liquid two-phase interactions,hydraulic and thermal parameter variation partial.Secondly,it discusses the research on large entrapped air migration with the filling process,which causes hydraulic parameter change in the whole pipeline.More details are as follows:Fluent is utilized to simulate V-shaped undulating pipeline section in order to gain flow pattern,hydraulic and thermal parameter variation during the whole filling process.Then the influences of physical parameters are discussed.Sensibility,principal component and canonical correlation analysis are used through statistical software as well.In this way,a safe and reliable direct commissioning project can be obtained as a result.Moreover,this research makes use of Fortran to develop gas-liquid migration interface tracking model,inlet and outlet boundary are treated particularly,and physical parameter and terrain undulating condition are taken into account.Finally,Visual Basic is adopted to design a common and simple software.The numerical results above can provide a technical scheme and theoretical foundation for future direct commissioning.