s. men, c. resagk, h. brauer, m. ziolkowski, m. kuilekov ilmenau university of technology 2d...
TRANSCRIPT
S. Men, C. Resagk, H. Brauer,
M. Ziolkowski, M. Kuilekov
Ilmenau University of Technology
2D Measurements of Magnetic Field near the Interface between Two Fluids Carrying
an Electrical Current
Motivation Theoretical Model Experimental Setup Results and Discussion Summary and outlook
Outline
MotivationSeveral MHD applications in processing of materials: Aluminum reduction, steel/iron making, glass melting, crystal growth, etc. require deep knowledge of behaviors of the surface/interface of electrically conducting fluids.
the use of probes is difficult or even impossible (limited access and hostile environment).
necessary to develop appropriate methods for cell diagnosis.
• Build up a magnetic sensor system to detect weak magnetic field (~nT);
• Develop optical techniques to observe interface displacement;
• Identify the main interface shape features by means of MFT.
Magnetic Field Tomography (MFT)
Construct a highly simplified aluminium reduction cell to investigate a MFT system
Theoretical Model
M
Mm
N
nmnmmn mrkJAr
1
cos,
V
o Vdrr
rrrJrB 34
Experimental Setup
CCD camera
Lightsheet laser
Two-fluid cell:KOH+GaInSn
Pneumaticshaker
Specifications:Measuring range: ±100µTOutput voltage: ±18.5mV/µTNoise: 30pT/HzBandwidth(-3dB): DC to 1.25kHzLinearity: 0.25%Orthogonality: 1°Operating temp: -40~+85°CZero drift: 100nT/KSupply voltage: 5V ±0.1V DCSupply current: 5mA effOutput impedance: <1kDimensions— sensor: 2mm15mm electronics: 26mm
2D fluxgate sensor-FXM 205
Optical measurement of interface oscillation
Results and discussion
Mode 11 : fshaker=7.2-7.6Hz
fshaker=7.3Hz, Idc=1.0A, A=10.17mm
Mode 21 : fshaker=9.3-9.6Hz
fshaker=9.4Hz, Idc=1.0A, A=8.28mm
electrolyteelectrolyte
liquid metalliquid metal
BBzz
BBrr
JJ00
Simulation of interface oscillation
mode 11, A=10mm
Simulation of interface oscillation
mode 21, A=8.0mm
Schematic of data acquisition and processing
Signals of eight Bz and Br at fshaker=7.3Hz, z=57.5mm
Magnetic field measurements
Peak at 3.65Hz Subharmonic at interface
Contour line of mode 11 at 1.0A, fshaker=7.3Hz
Forward calculationMeasurements
Bz Bz
Br Br
A=9.5-10.5mm A=10.0mm
Mode 21 at fshaker=9.4Hz, Idc=1.0A
Forward calculationMeasurement
A=7.5-8.5mm A=8.0mm
Interface modemn, A
FEM3DExtract current
density
Biot-Savartlaw
Magnetid flux densityIn sensor positions
Flow chart of interface reconstruction
Reconstructed interface
CF12% CF 16%
mode 21mode 11
%100
1
22
1
22
Nsensor
i
measri
measzi
Nsensor
i
measriri
measzizi
BB
BBBBCF
10
-10
1. A sensor ring consisting of eight 2D sensors is suitable to measure the magnetic field near the oscillating interface between two electrically conducting fluids for modes m2, n3.
2. Forward calculation by FEM3D based on the optical measurement is consistent well with the experimental results.
3. Evolutionary algorithm is effective for the magnetic field tomography to reconstruct a non-axisymmetric interface of a low mode.
4. Better experimental results (smaller reconstruction error) can be expected when more sensors in one ring and/or more sensor rings are applied.
5. A rectangular cell whose shape is similar to an aluminium reduction cell will be investigated a little later.
Summary and outlook
Thank you for your attention!