Yuri Kolesnikov

Constrained flow around a magnetic obstacle

Many practical applications exploit an external local magnetic field -- magnetic obstacle -- as an essential part of their constructions. Recently, it has been demonstrated that the flow of an electrically conducting fluid influenced by an external field can show several kinds of recirculation. The present paper reports a 3D numerical study whose some results are compared with an experiment about such a flow in a rectangular duct.

Application of Lorentz Force Velocimetry to Open Channel Flow

Lorentz Force Velocimetry (LFV) is a noncontact method for flow measurement in electrically conducting fluid, especially in high temperature, opaque and aggressive molten metal. The principle is based on exposing the flow to a magnetic system and measuring the drag force acting upon it [1]. The aim of present paper is to study the application of LFV for open channel liquid metal flows, to numerically obtain the relationship between the measured Lorentz force and the flow rate. This provides the calibrating criterion of LFV. To this end, we firstly investigate a metal bar with different cross-section shapes passing through the magnetic system; Secondly, we study the relationship by a multiphysics numerical model fully coupling Navier-Stokes equations and Maxwell equations.

Vortex dynamics in the wake of a magnetic obstacle

We present an experimental study about the vortex dynamics in liquid metal flow under the influence of confined non-homogeneous magnetic field, so-called magnetic obstacle. A permanent magnet installed on a moving rail beneath a cell, filled with eutectic alloy GaInSn, moves with constant velocities with the corresponding Reynolds number from

Experimental investigation of the transient phase of the Lorentz force response to the time-dependent velocity at finite magnetic Reynolds number

Re = \text{125 to 2000}

Application of the ultrasonic velocity profile method to the mapping of liquid metal flows under the influence of a non-uniform magnetic field

Re=125 to 2000. The liquid metal flow patterns are recorded using a camera moving with the magnet. Small bubbles, which are a product of hydrochloric acid and GaInSn oxide reaction, illuminate the streamlines which are to be presented here. As the velocity and hence Reynolds number and interaction parameter change, complicated phenomena are visible inside the channel including formation of vortices or their suppression, symmetry breakdown, vortex duplication and vortex shedding. The vast number of instability-related phenomena present in the flow past a magnetic obstacle make it worth investigating. This leads to a better understanding of magnetic obstacle or even turbulence. Since it is impossible to present all the observed phenomena in detail in one paper, here we present only a few illustrative examples to provide an overall view of the phenomena occurring. We conclude with a discussion of the flow instabilities and comparison between the results of our experiments and the theoretical predictions of the reference literature.

Method and arrangement for the contactless inspection of moving electrically conductive substances

Measuring flow rates of liquid metal flows is of utmost importance in industrial applications such as metal casting, in order to ensure process efficiency and product quality. A non-contact method for flow rate control is described here. The method is known as time-of-flight Lorentz force velocimetry (LFV) and determines flow rate through measurement of Lorentz force that act on magnet systems that are placed close to the flow. In this method, a vortex generator is used to generate an eddy in the flow, with two magnet systems separated by a known distance placed downstream of the vortex generator. Each of the magnet systems has a force sensor attached to them which detects the passing of the eddy through its magnetic field as a significant perturbation in the force signal. The flow rate is estimated from the time span between the perturbations in the two force signals. In this paper, time-of-flight LFV technique is demonstrated experimentally for the case of liquid metal flow in a closed rectangular duct loop that is driven by an electromagnetic pump. A liquid metal alloy of gallium (Ga), indium (In) and tin (Sn)—GaInSn—is used as the working fluid. In contrast to prior works, for the first time, three-dimensional strain gauge force sensors were used for measuring Lorentz force to investigate the effect of flow disturbances in different directions for flow measurements by the time-of-flight LFV method. A prototype time-of-flight LFV flowmeter is developed, the operation of which in laboratory conditions is characterised by different experiments.

Electromagnetic stirring of glass melts using Lorentz forces: Experimental results

The working principle of Lorentz force velocimetry (LFV) is based on a linear dependence between measured force and velocity. We consider a case when a violation of that linear law takes place in order to take this effect into account for LFV. The response of the Lorentz force to a time-dependent velocity of solid conducting rods is experimentally studied. Solid conductors were chosen due to the fact that at a limited length of imposed magnetic field the end effects of secondary field generation are identical both in liquid and solid conductors. Thus one can simulate clearly a distortion of the imposed magnetic field in the case of non-stationary fluid flows. The magnetic Reynolds number based on advection time was of the order of unity. It is demonstrated that magnetic field advection effects lead to a Lorentz force difference in low- and finite- cases. The induced magnetic field measurements and experimental estimation of the eddy current density are reported.

Calibration of the Lorentz force flowmeter

Zusammenfassung In der Metallurgiebranche fehlen derzeit geeignete Verfahren zur präzisen Erfassung, Regelung und Dosierung der zwischen den einzelnen Produktionsstufen übertragenen Mengen an Metallschmelze. Durch den Einsatz des patentierten Verfahrens der Lorentzkraft-Anemometrie, bei dem der direkte Kontakt zur heißen Metallschmelze nicht erforderlich ist, lässt sich diese Aufgabe lösen und somit ein nachhaltiger Beitrag zu zukünftig energie- und kostenoptimierter Produktion leisten. Im vorliegenden Artikel werden das Prinzip des Verfahrens erläutert und die wissenschaftlich-technischen Wege zur Entwicklung, Prüfung und Kalibierung von entsprechenden Lorentzkraft-Anemometern vorgestellt. Desweiteren werden Beispiele aktueller Anwendungen der Lorentzkraft-Anemometrie in der Praxis diskutiert. Abstract