The Research Of Based On Rotating Magnetic Field Multi-electrode Electromagnetic Flow Measurement Method

Electromagnetic flowmeter has become a kind of mature flow measurement instrumentafter decades of development, which is widely used in engineering survey and experimentalstudy. However, the traditional electromagnetic flowmeter only measure average flowvelocity of axisymmetric flow, it will produce larger measurement errors in the asymmetricflow. The greater the error，the more serious asymmetric. However in modern industrial andexperimental study it is not only need to measure the fluid flow in various type of averageflow velocity, and hope to be able to realize the online velocity profile visualization. Thus,the multi-electrode electromagnetic flowmeter be introduced.This paper reviewed the electromagnetic flowmeter and tomography technologyresearch present situation and the development trend, and did theoretical analysis numericalcalculate for multielectrode electromagnetic flowmeter, and combination of rotating magneticfield and multielectrode put forward a flow measurement methods.This paper introduced the traditional electromagnetic flowmeter, multi-electrodeelectromagnetic flowmeter and tomographic imaging technology. this paper introduced themeasurement principle of traditional electromagnetic flowmeter, the measurement theory ofelectromagnetic flowmeter be detailed analysis on the basis of maxwell equations, it isconcluded that the electromagnetic flowmeter basic differential equation. Finally, this paperintroduced the working principle of the multi-electrode electromagnetic flowmeter, deducedthe weight function of multi-electrode electromagnetic flowmeter. The simulation graphicsshows as long as the electrode several is enough, sensitivity of electromagnetic flowmeter topattern can be eliminated, introduced each electromagnetic parameters of the excitationsystem in rotating magnetic field calculation in detailed, and by use of DDS technologies to produce three-phase sine wave excitation signal.By the matlab simulation software to simulate the distribution of rotating magnetic field,proved rotating magnetic field and multi-electrode electromagnetic flowmeter has notsensitive to flow model, and can achieve real-time reconstruction of flow velocity. This paperdid useful exploration on the asymmetric flow velocity measurement and the flow patternvisualization.