Research On Measurement Characteristics Of Gas-liquid Two-phase Flow In A New Differential Pressure Flowmeter With Inner And Outer Tubes

Gas-liquid two-phase flow is widely used in the fields of oil,chemical,pipeline transportation and nuclear reactors.On-line non-separation measurement of gas-liquid two-phase flow is of great significance to safety production,energy saving and emission reduction,so more and more concern has been put for it.This paper adopts a new type of Inner and outer pressure differential pressure flowmeter designed and optimized by our team,the characteristics of single-phase and gas-liquid two-phase flow measurement are studied.The paper mainly completes the following works:In this paper,the existing experimental platform is improved,so that data acquisition is more accurate and reliable.Experiments were conducted in single-phase of water flow range of 1 m³/h to 11 m³/h,and the mathematical model of the single-phase out flow coefficient C was fitted.The maximum relative error between the measured value and the actual value of the single-phase water flow is 1.6%.The change range of pressure loss is-0.1-4kPa.The pressure loss ratio increased first and then decreased,and the change trend of the 6 groups of experimental data is the same,the pressure loss ratio ranged from 0.15 to 0.4.Based on the characteristics of single-phase measurement,the study on measurement characteristics of gas-liquid two-phase flow was studied.The two-phase test conditions are as follows:the water flow rate is 2 m³/h-11 m³/h,and the air flow rate is 0.12 m³/h-0.6 m³/h.By analyzing the differential pressure signal and the variation characteristics of Fr_l,Fr_g,a two phase mass model is established,The corresponding flow pattern is piecewise matched by Fr_l,Fr_g and the correction coefficient G introduced,the two-phase mass flow prediction model of slug flow and bubble flow is obtained respectively in the case of known phase hold.The experimental results show that the experimental results show that the maximum visual error of the slug flow mass flow rate is 3%,and the maximum visual error of the bubble flow mass flow rate is 2.5%.The pressure loss ratio and the mathematical model of Fr_g and X_LM were subdivided by analyzing the pressure loss ratio and the change rule of X_LM,then the void fraction is obtained.The relative error of the liquid phase holdup is 2%,the relative error of mass flow is less than3%,the relative error of liquid phase mass flow and gas phase mass flow are 4%and 35%,respectively.The relative error of liquid phase of bubbly flow is less than 1.4%,the relative error of the two-phase mass flow was within 2.5%of the whole,the relative error of the liquid mass flow and the mass flow were 3.5%and 30%,respectively.Two parameters measurement of phase holdup and flow rate is realized by using differential pressure and pressure loss ratio measured by new differential pressure flowmeter,which provides a new method for the non separation measurement of the gas-liquid two phase flow.