Experiment And Research On Volume Fraction Detection Of Gas-liquid Two-phase Flow

The gas-liquid two-phase flow in pipelines exists in industrial processes such as petroleum,chemical,power,metallurgy,carbon capture and storage(CCS),and its parameter detection is directly related to the safety and economic operation of equipment.As gas-liquid two-phase flow is a recognized,complex,and nonlinear dynamic system,there are time-varying interphase forces and interfaces,as well as phase interface effects and interphase velocities,Therefore,multiphase flow is called difficult to measure fluid in academic circles,and its parameters are difficult to detect in real time.In view of the important theoretical significance and significant practical value of real-time measurement of multiphase fluid parameters,the measurement of gas-liquid two-phase fluid parameters has been a hot research issue for decades,and many measurement methods have been developed.However,due to the complexity of the problem,there are not enough methods that can be really applied to the industrial field in the research achievements that have been achieved.On the basis of understanding and mastering existing methods and technologies,this paper aims to achieve the effectiveness requirements of parameter detection for gas-liquid two-phase flow in pipelines,such as CO2 gas-liquid two-phase flow involved in CCS processes and oil gas two-phase flow in petroleum industry processes.It constructs a discrete phase volume fraction direct measurement method with approximate linear input output characteristics and uniform field.To this end,a capacitive sensor has been developed,The main innovative work of this paper lies in:(1)A real-time measurement scheme for the volume fraction of gas-liquid twophase flow based on a coaxial cylindrical electrode array capacitive sensor for annular measurement space is proposed.On the process pipeline,install a circular non-metallic sensor pipeline with a flow area that is exactly the same as the cross-sectional area of the process pipeline.The circular space is composed of two coaxial inner and outer cylindrical surfaces,and four metal electrode plates with coverage angles close to 90°are embedded on the 360° circumference of the inner and outer cylindrical surfaces,forming four independent capacitive sensors.The four capacitive sensors divide the circular measurement space into four measurement subspaces,And the discrete phase volume fraction of gas-liquid two-phase flow in the corresponding subspace is converted into a capacitance signal output,achieving direct measurement of the discrete phase volume fraction of gas-liquid two-phase flow in the pipeline.(2)Using numerical simulation software,sensitivity field analysis was conducted on the annular measurement space created by the proposed coaxial cylindrical electrode array capacitive sensor.Compared with traditional capacitive sensors,the sensitivity and measurement field uniformity of this measurement device were significantly improved.(3)A static measurement experimental scheme was designed,and the correctness and effectiveness of the solution were verified using static experimental methods.