Study On Volume Fraction Detection Base On Magnetic Resonance For Gas-liquid Two-phase Flow

Gas-liquid two-phase flow phenomenon exists in people's life in large quantities,and its detection technology is widely used in many aspects such as medical treatment,energy,chemical industry,etc.In gas-liquid two-phase flow,the determination of volume fraction is very important because it's the basis for the description of the flow behavior and the predicting of the mass,momentum and energy transfer.So the determination of volume fraction is great significance in the detection of gas-liquid two-phase flow.In the earlier research,intrusive sensor measurement method was mainly used.However,the sensor probe is directly in contact with the measured two-phase flow,the sensor probe is easy to be corroded,the measurement stability of the detection system is poor.With the deepening of the study of two-phase flow,some researchers have proposed the electromagnetic induction method for volume fraction detection of gas-liquid two-phase flow based on the conductivity and magnetic permeability characteristics of two-phase flow.Since the measurement does not need to directly contact the measured two-phase flow,the stability of the detection system is better,which has become a hot spot of current research.However,the existing electromagnetic induction method for detecting the volume fraction of gas-liquid two-phase flow has some problems,such as poor measurement accuracy and low signal strength.A magnetic resonance method for volume fraction detection of gas-liquid two-phase flow is proposed in this paper.Firstly,the distance between the transmitting coil and the receiving coil is measured.Then,the influence of pipeline length on the measurement results is studied,and the measurement model is determined.Based on the measurement model,the relationship between the volume fraction of laminar flow and annular flow and the load voltage of the measurement system is studied,and a mathematical model for the calculation of gas-liquid two-phase flow is established,finally the impedance information of the two-phase flow is described in detail.Through mathematical calculation and numerical simulation,the detection signal strength and accuracy of magnetic resonance gas-liquid two-phase flow volume fraction detection technology are improved compared with the existing electromagnetic induction gas-liquid two-phase flow volume fraction detection method.Finally,a two-phase flow volume fraction test platform is built to verify the feasibility of the proposed method.