Alternative transient eddy-current flowmetering methods for liquid metals
| Autor: | Jānis Priede, Richard Looney |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Physics - Instrumentation and Detectors
media_common.quotation_subject 0207 environmental engineering Magnetic Reynolds number 02 engineering and technology 01 natural sciences Asymmetry Flow measurement law.invention 010309 optics Physics::Fluid Dynamics law 0103 physical sciences Fluid dynamics Eddy current Electrical and Electronic Engineering 020701 environmental engineering Instrumentation media_common Physics Mechanics Zero crossing Computer Science Applications Magnetic field Modeling and Simulation Transient (oscillation) |
| Popis: | We present a comprehensive numerical analysis of alternative transient eddy-current flowmetering methods for liquid metals. This type of flowmeter operates by tracking eddy-current markers excited by the magnetic field pulses in the flow of a conducting liquid. Using a simple mathematical model, where the fluid flow is replaced by a translating cylinder, a number possible alternative measurement schemes are considered. The velocity of the medium can be measured by tracking zero crossing points and spatial or temporal extrema of the electromotive force (emf) induced by transient eddy currents in the surrounding space. Zero crossing points and spatial extrema of the emf travel synchronously with the medium whereas temporal extrema experience an initial time delay which depends on the conductivity and velocity of the medium. Performance of transient eddy-current flowmetering depends crucially on the symmetry of system. Eddy current asymmetry of a few per cent makes the detection point drift with a velocity corresponding to a magnetic Reynolds number $Rm\sim 0.1.$ With this level of asymmetry transient eddy-current flowmetering can be reliably applicable only to flows with $Rm\gtrsim 0.1.$ A more accurate symmetry adjustment or calibration of flowmeters may be necessary at lower velocities. Comment: 16 pages, 9 figures (to appear in Flow Meas. Instrum.) |
| Databáze: | OpenAIRE |
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