Magnetic obstacle: results from numerical reconstructions of experimental data. - In: Proceedings of the 10th PAMIR International Conference on Fundamental and Applied MHD, (2016), S. 574-578
We present results from numerical reconstructions of magnetic obstacle experiments in which a moving permanent magnet drives a free-surface flow in a container filled with liquid metal (GaInSn). The results cover different flow regimes, such as stationary (in the reference system of the moving magnet) so-called six vortex structures, as well as time-dependent flows. The numerical results show that - although the liquid metal layer is thin - the flow structure is highly three dimensional. We conclude that the experimental technique for streamline visualization (gas bubbles at the surface of the liquid metal) is insufficient to picture the occurring flow structure. To underpin our conclusion, we introduce a modified numerical model that aims to mimic the movement of the gas bubbles. The results of the modified model and the experiments are in excellent agreement. Furthermore, Lorentz forces obtained from simulations match well with those from the experiments.
Scaling of turbulent heat and momentum transfer for magnetoconvection in a vertical magnetic field. - In: Proceedings of the 10th PAMIR International Conference on Fundamental and Applied MHD, (2016), S. 532-536
Experimental study on bubble rising in liquid GaInSn using Local Lorentz Force Velocimetry (LLFV). - In: Proceedings of the 10th PAMIR International Conference on Fundamental and Applied MHD, (2016), S. 243-246
Numerical simulation of swirling flow in the pipe under non-uniform magnetic field. - In: Proceedings of the 10th PAMIR International Conference on Fundamental and Applied MHD, (2016), S. 234-237
The effects of axial magnetic field on turbulence in Taylor-Couette flow. - In: Proceedings of the 10th PAMIR International Conference on Fundamental and Applied MHD, (2016), S. 224-228
Dry calibration of a new generation local Lorentz force flowmeter. - In: Proceedings of the 10th PAMIR International Conference on Fundamental and Applied MHD, (2016), S. 198-202
DNS of natural convection in liquid metal with strong magnetic fields in rectangular enclosures. - In: Proceedings of the 10th PAMIR International Conference on Fundamental and Applied MHD, (2016), S. 67-71
New developments on Lorentz force velocimetry for weakly conducting fluids. - In: Proceedings of the 10th PAMIR International Conference on Fundamental and Applied MHD, (2016), S. 1-5
Local Lorentz force flowmeter at a continuous caster model using a new generation multicomponent force and torque sensor. - In: Measurement science and technology, ISSN 1361-6501, Bd. 27 (2016), 6, S. 065302, insges. 9 S.
Lorentz force velocimetry is a non-invasive velocity measurement technique for electrical conductive liquids like molten steel. In this technique, the metal flow interacts with a static magnetic field generating eddy currents which, in turn, produce flow-braking Lorentz forces within the fluid. These forces are proportional to the electrical conductivity and to the velocity of the melt. Due to Newton's third law, a counter force of the same magnitude acts on the source of the applied static magnetic field which is in our case a permanent magnet. In this paper we will present a new multicomponent sensor for the local Lorentz force flowmeter (L2F2) which is able to measure simultaneously all three components of the force as well as all three components of the torque. Therefore, this new sensor is capable of accessing all three velocity components at the same time in the region near the wall. In order to demonstrate the potential of this new sensor, it is used to identify the 3-dimensional velocity field near the wide face of the mold of a continuous caster model available at the Helmholtz-Zentrum Dresden-Rossendorf. As model melt, the eutectic alloy GaInSn is used.
http://dx.doi.org/10.1088/0957-0233/27/6/065302
An experimental prototype of an innovative fluid-driven electromagnetic stirring technique. - In: Journal of iron and steel research, international, ISSN 2210-3988, Bd. 23 (2016), 5, S. 422-427
A new electromagnetic stirring technique that is driven by hydrodynamic forces was presented. This technique offers the following advantages. First, the stirrer can be immersed in the liquid metal, thereby significantly increasing the penetration depth of the electromagnetic forces and significantly improving the stirring efficiency; thus, this technique is particularly suitable for large-scale liquid metal. Second, under certain conditions, this technique can overcome difficulties that are encountered with traditional stirrers, such as accessing regions that are difficult to reach in working spaces with complex or narrow shapes. This stirrer also has a simpler structure than a traditional stirrer; thus, the design can be easily modified, and no external power supply is required. An experimental prototype was also presented for controlling the fluid flow rate, thereby controlling the electromagnetic force and velocity field of the driven liquid metal. The velocity distribution in a liquid GaInSn alloy under fluid-driven electromagnetic stirring was quantitatively measured using ultrasonic Doppler velocimetry (UDV). The primary results show that a remarkable velocity field has been achieved and that fluid-driven electromagnetic stirring is an effective means of stirring liquid metal. Finally, the potential applications of this technique in industry, along with key challenges, were discussed.
http://dx.doi.org/10.1016/S1006-706X(16)30067-X