Study On The Characteristics Of Inner-Outer Tube Differential Pressure Flowmeter With Single End Pressure Extraction

Flow measurement is an important technology in metrology science.Gas-liquid two-phase flow is a difficult and key point in the field of flow measurement,and plays an important role in petroleum,chemical,metallurgical,natural gas and other industrial fields.Differential pressure flow meters are widely used in the field of gas-liquid two-phase flow because of their stability and reliability.In this paper,based on this type of differential pressure flowmeter,the water flow rate and the flow rate of resin pipe flowmeter are tested and analyzed.To make the flow measurement more accurate and improve the existing experimental platform,a multiphase flow control and data acquisition system is built by combining the Lab VIEW interface with the PLC-1200 system.The mathematical model of differential pressure value,Reynolds number and outflow coefficient is established for the water flow experiment of two kinds of differential pressure Flowmeter.The relative error of fitting outflow coefficient C metal tube Flowmeter is less than±7%,and that of resin tube Flowmeter is less than±3%;the reynolds number of pipe Flowmeter is fitted by subsection method,the relative error of outflow coefficient C is less than±1.2%,and the relative error of resin pipe Flowmeter Reynolds number fitting outflow coefficient C is less than±4%.The flow volume experiment,the metal tube flow meter outflow coefficient is modeled by section modeling method.The relative error of differential pressure value fitting is within±4%.When the flow value is more than 100 m~3/h,the relative error is stable at about±1%,and the reynolds number fitting error is within±0.5%.Through the theoretical derivation,the theoretical formula model C the roughnessξof the inner wall of the pipeline and the outflow coefficient is obtained,and the change of the outflow coefficient C is the result of the joint influence of the roughnessξof the inner wall of the pipeline and the Reynolds number Re the dimensionless parameters.Through the values of velocity,density,viscosity coefficient and Reynolds number of fluid,the friction factorsλ,friction factors of internal surface roughness of pipelineλin the range of 0.0211～0.0235 and 0.0352～0.0372,and the outflow coefficient factorλin the range of0.0336～0.0351,and the outflow coefficient decreases with the increase of friction factor.