Research On Blood Flowmeter Based On Multi-electrode Electromagnetic Measurement

With the progress and development of technology,the application of electromagnetic flowmeter in the field of flow measurement has become more and more widely,and the research of multi-electrode electromagnetic flowmeter has opened up new fields for flow measurement.In this paper,based on the theory and method of multi-electrode electromagnetic measurement,it is applied to the monitoring of blood flow velocity,and the blood flow velocity information of the human body is obtained by picking up the induced voltage of the outer wall of the blood vessel.Firstly,the measurement principle of electromagnetic flowmeter is introduced,and the relevant theory of multi-electrode electromagnetic flowmeter developed from traditional two electrodes electromagnetic flowmeter is emphasized.Based on the Shercliff function,the concept of elemental weight function is introduced and it shows the contribution of the velocity in the measurement area to the induced voltage between different electrode pairs.By comparing the common excitation method and the characteristics of the excitation coil,the C-type coil is chosed as the excitation system.Secondly,the distribution of weight function for multi-electrode electromagnetic flow is simulated,which provides the basis for further research on the distribution of electrode arrays.Through the discussion of the stability of the weight function,it provides the theoretical basis for the reconstruction of the velocity of the multi-electrode electromagnetic flowmeter.Thirdly,the geometrical model of the multi-electrode electromagnetic blood flowmeter is constructed in the COMSOL Multiphysics software.The magnetic field induced intensity distribution of the C-shaped coil at the flow cross section is simulated as well as the induced voltage.According to the characteristics of blood flow velocity,the measurement cross section of blood flowmeter was divided,and the velocity distribution at the cross section is reconstructed by simulated induced voltage.Finally,the C-type coil is designed and fabricated by calculating the magnetic field strength at the air gap.According to the conductivity of human blood and tissue,as well as the characteristics of artery and vein,the measuring pipe of multi-electrode electromagnetic blood flowmeter is processed.