Online Detection And Correction Of Erosion In Standard Orifice Plate Flow-meters

The standard orifice flow-meter is a representative differential pressure flow-meter,employed widely in industrial sites and other fields.However,with chronic impact of the fluid,erosion and bluntness appear at square edges of orifice plates,which alters measurement values and causes inaccuracy.Since orifice plates are installed inside pipes,traditional methods can hardly detect the extent of erosion without a halt in production.In terms of this issue,this article conducts a study on online detection and correction towards erosion of standard orifice plates.Theoretical analysis,CFD simulation,and experiments with real flows will be applied in this research;The groundwork of stimulation study introduced in the first place,including schemes of Gambit meshing,physical modeling,and stimulation models of turbulence,provides a solid foundation for the following research.The study toward characteristics of downstream flow field of standard orifice plates is conducted with Fluent simulation model;stability of structure parameters(the length of downstream recirculation zone,the position of vortex center,etc.)and variation tendency within different operation condition are analyzed quantitatively.Based on the concept of differential pressure ratio factor,proposed by other scholar,the article verifies its stability in normal orifice plates flow field,quantitatively analyzes and concludes variation patterns of differential pressure ratio factor in structures of orifice plates of different sizes,and testifies the feasibility of detecting the erosive degree of plates utilizing differential pressure ratio factor.With DPM model in Fluent simulation,solid particles as the discrete phase,this article quantitatively analyzes particular locations and extent of erosion in orifice plates and chooses simulation scheme of eroded plates logically according to tracks of particles and comparison of parameters(such as wall shear stress,turbulence intensity and fluid velocity,etc.).After study on downstream flow field with eroded plates and variation patterns of differential pressure ratio factor,the concept of resolution of differential pressure ratio factor is presented,which is an another important reference index of detecting erosive degree of orifice plates.With comparison of simulation data,optimization in choices of measuring points of pressure is completed based on balance between the stability and the resolution of differential pressure ratio factor.With experiments with real flows,the result of CFD simulation computation is testified,and the capability of differential pressure ratio factor in detecting erosive degree of standard orifice plates is proved.After analysis and conclusion of a great abundance of simulation computing results,this article builds up an integrated function correspondence between differential pressure ratio factor and erosive degree of orifice plates and online correction models,which is preliminarily capable to be promoted in industrial production environment.