A universal noncontact flowmeter for liquids

Wegfraß, Andre; Diethold, Christian; Werner, Michael; Fröhlich, Thomas; Halbedel, B.; Hilbrunner, Falko; Resagk, Christian; Thess, André

doi:10.1063/1.4714899

Cited by 30 publications

(42 citation statements)

References 17 publications

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“…First, there is a growing interest to extend the applicability of Lorentz force velocimetry to highly viscous fluids like glass melts. 46 Such flows are characterized by low Reynolds numbers. And second, the interaction of a dipole with a laminar flow represents a fundamental problem which is interesting in its own right.…”

Section: Discussionmentioning

confidence: 99%

Interaction of a small permanent magnet with a liquid metal duct flow

Heinicke

Tympel

Pulugundla

et al. 2012

Journal of Applied Physics

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If a permanent magnet is located near a liquid metal flow, the magnet experiences a Lorentz force, which depends on the velocity of the flow. This effect is embodied in a noncontact flow measurement technique called Lorentz force velocimetry (LFV). Although LFV is already under way for global flow measurement in metallurgy, the possibility of using LFV for local velocity measurement has not yet been explored. The present work is devoted to a comprehensive investigation of the Lorentz force acting upon a permanent magnet near a liquid metal flow in a square duct when the size of the magnet is sufficiently small to be influenced by only parts of the fluid flow. We employ a combination of laboratory experiments in the turbulent regime, direct numerical simulations of laminar and turbulent flows using a custom-made code, and Reynolds-averaged Navier-Stokes (RANS) simulations using a commercial code. We address three particular flow regimes, namely the kinematic regime where the back-reaction of the Lorentz force on the flow is negligible, the low-Reynolds number dynamic regime and the high-Reynolds number dynamic regime both being characterized by a significant modification of the flow by the Lorentz force. In all three regimes, the Lorentz force is characterized by a nondimensional electromagnetic drag coefficient CD, which depends on the dimensionless distance between the magnet and the duct h, the dimensionless size of the magnet d, the Reynolds number Re, and the Hartmann number Ha. We demonstrate that in the kinematic regime, CD displays a universal dependence on the distance parameter, expressed by the scaling laws CD ∼ h−2 for h ≪ 1 and CD ∼ h−7 for h ≫ 1. In the dynamic regime at low Re, the magnet acts as a magnetic obstacle and expels streamlines from its immediate vicinity. In the dynamic regime at high Re, we present experimental data on CD(Re) for 500 ≤ Re ≤ 104 and on CD(h) for 0.4 ≤ h ≤ 1 and demonstrate that they are in good agreement with numerical results obtained from RANS simulations for the same range of parameters.

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Section: Discussionmentioning

confidence: 99%

Interaction of a small permanent magnet with a liquid metal duct flow

Heinicke

Tympel

Pulugundla

et al. 2012

Journal of Applied Physics

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“…Here, we propose a type of contactless flow meter which overcomes those problems associated with uncertainties that are unavoidable while using gravimetric method discussed in papers reported by Wegfrass et al, 5,9 for flow metering or through frictional contact mechanics. 7,8 Moreover, performances of those methods become critical, whereas for gravimetric case tracking range plays a key role on accuracy of measurements, in frictional case measurements were performed on liquid metals by conductivity of 10 6 times higher than that of electrolytes we are focused here.…”

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confidence: 97%

“…Study presented here is based on the advancement in flow metering of electrolytes through measurements of the Lorentz force (LF), originally introduced by Wegfrass et al, 5 and later extended to the limits of the actual setup under considerations of its mechanical and electromagnetic characteristics. 9 In particular, this paper addresses a method for noncontact LF measurements by direct compensation of induced forces typically in the order of F $ 10 À6 N for electrolytes, which has r $2-20 S/m conductivity.…”

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confidence: 99%

“…A magnetohydrodynamic 1 (MHD) approach, besides of being widely popular in material processing, 2 flow casting, and metering, also garnered extensive attention by recent studies on flow rate measurement applications, particularly on developments of so called noncontact flowmeters. [3][4][5][6][7][8] An alternative noncontact and precise measurement technique for measuring flow rate of an electrically conducting medium required especially for cases when this medium, such as liquid metal or electrolyte solution, is hot, aggressive, or nontransparent.…”

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confidence: 99%

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Direct Lorentz force compensation flowmeter for electrolytes

Vasilyan

Froehlich

2014

Appl. Phys. Lett.

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“…LFV has been applied successfully to industrial type flows and to electrolytes in the laboratory [7][8][9]. All of these measurements have been volume flux measurement.…”

Section: Introductionmentioning

confidence: 99%

Contact-free measurement of the flow field of a liquid metal inside a closed container

Heinicke

2014

EPJ Web of Conferences

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Abstract. The measurement of flow velocities inside metal melts is particularly challenging. Due to the high temperatures of the melts it is impossible to employ measurement techniques that require either mechanical contact with the melt or are only adaptable to translucent fluids. In the past years a number of electromagnetic techniques have been developed that allows a contact-free measurement of volume flows. One of these techniques is the so-called Lorentz Force Velocimetry (LFV) in which the metal flow is exposed to an external, permanent magnetic field. The interaction between the metal and the magnet not only leads to a force on the fluid, but also on the magnet. The force can be measured and is proportional to the velocity of the melt. Moreover, by using a small permanent magnet it is possible to resolve spatial structures inside the flow. We will demonstrate this using a model experiment that has been investigated with different reference techniques previously. The experimental setup is a cylindrical vessel filled with a eutectic alloy which is liquid at room temperature. The liquid metal can be set into motion by means of a propeller at the top of the liquid. Depending on the direction of rotation of the propeller, the flow inside the vessel takes on different states. Beside the vessel, we place a Lorentz Force Flowmeter (LFF) equipped with a small permanent magnet. By measuring the force on the magnet at different positions and different rotation speeds, we demonstrate that we can qualitatively and quantitatively reconstruct the flow field inside the vessel.

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A universal noncontact flowmeter for liquids

Cited by 30 publications

References 17 publications

Interaction of a small permanent magnet with a liquid metal duct flow

Interaction of a small permanent magnet with a liquid metal duct flow

Direct Lorentz force compensation flowmeter for electrolytes

Contact-free measurement of the flow field of a liquid metal inside a closed container

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