| In the process of oil and gas exploitation and transportation,in order to ensure the real-time and accurate output,it is necessary to use flow meter for accurate measurement.The shallow water multiphase flow meter studied in this paper is developed for measuring the transportation medium for gas-liquid multiphase.This paper takes a shallow multiphase flow meter as the research object choosing Eulerian fluid model and RNG k-ε.The turbulence model is used for numerical calculation.Firstly,static analysis and transient dynamic analysis are carried out for the flow meter at 3 depths;Then the internal flow characteristics of flowmeter under variable flow pure oil and solid-liquid two-phase conditions are calculated and analyzed;Finally,the wear characteristics of flowmeter under different conditions are analyzed and the wear amount of flowmeter is predicted.Based on the wear amount of flowmeter,the measurement reliability of flowmeter after abrasion is studied.The following conclusions are obtained:(1)Static analysis is carried out under extreme and normal conditions for the overcurrent pressure-bearing section at water depths of 300 m,400 m and 500 m respectively.The maximum values of stress,strain and total deformation under each condition are 146.3MPa,0.00073 and 0.0152 mm respectively.Through transient dynamics analysis,the maximum values of stress and strain under each working condition are 186.2MPa and 0.020 respectively.The maximum stress and structural deformation under all operating conditions meet the relevant safety requirements,which indicates that the structural reliability meets the requirements.(2).Under the condition of pure oil with variable flow rate,the overall flow rate inside the flow meter extends inwards along the radial direction,with the highest rate near the center and the lowest speed at the wall affected by the boundary layer.Solid particle accumulation extends from throat position of flow meter to inlet section under solid-liquid two-phase condition.When the volume fraction of solid and the diameter of solid particles are constant,the flow rate of flow meter is the main parameter that affects the aggregation degree of solid particles near the inner wall of multiphase flow meter.(3)Under the gas-liquid-solid three-phase condition,the solid volume fraction has no obvious influence on the flow characteristics inside the flowmeter.With the increase of the solid volume fraction,the mass concentration of the discrete phase inside the flowmeter increases,and the distribution range also expands.With the increase of solid volume fraction,the mass concentration of discrete phase in the flow meter gradually changes from scattered distribution to sheet distribution.(4).By predicting the wear depth of the flowmeter,the flowmeter is modeled again.Through numerical simulation,the solid volume fraction is 0.05%.Under common flow conditions,the error caused by inner wall abrasion on flowmeter flow and the error caused by theoretical flow are less than 1% after 5,10,15 and 20 years of use. |
