1 / 23

New possibilities for velocity measurements in metallic melts S. Eckert , G. Gerbeth, F. Stefani

New possibilities for velocity measurements in metallic melts S. Eckert , G. Gerbeth, F. Stefani Department Magnetohydrodynamics, Forschungszentrum Rossendorf P.O. Box 510119, D-01314 Dresden, Germany, http://www.fz-rossendorf.de/FWS/FWSH E-mail: s.eckert@fz-rossendorf.de.

tiger
Download Presentation

New possibilities for velocity measurements in metallic melts S. Eckert , G. Gerbeth, F. Stefani

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. New possibilities for velocity measurements in metallic melts S. Eckert, G. Gerbeth, F. Stefani Department Magnetohydrodynamics, Forschungszentrum Rossendorf P.O. Box 510119, D-01314 Dresden, Germany, http://www.fz-rossendorf.de/FWS/FWSH E-mail: s.eckert@fz-rossendorf.de Sino-German Workshop on Electromagnetic Processing of Materials Oct. 11-13, Shanghai, China

  2. Why do we need flow measurements in metallic melts ?  Knowledge about the flow field and the transport properties of the flow  Optimisation of products, technologies and facilities • better understanding of the process • validation of CFD models • on-line control and monitoring

  3. Current situation Commercial measuring techniques for liquid metal flows are almost not available ! Reasons • properties of the fluid (opaqueness, heat conductivity,..) • high temperatures • chemical reactivity • interfacial effects • external electromagnetic fields

  4. Goals • to develop measuring techniques for liquid metal flows at moderate temperatures  model experiments (T  300°C) • to extend the range of application towards higher temperatures

  5. Data of interest • flow rate • local velocity • fluctuations, turbulence level • flow pattern (velocity profiles, 3D-structure)

  6. List of measuring techniques • Local probes(invasive) • Electric Potential Probe (EPP, Vives Probe) • Mechano-Optical Probe (MOP) • Ultrasonic methods(non-invasive, but need contact) • Ultrasound Doppler Velocimetry (UDV) • Inductive methods(contact-less) • Inductive Flowmeter (IFM) • Contactless Inductive Flow Tomography (CIFT) • X-ray radioscopy • Local probes(invasive) • Electric Potential Probe (EPP, Vives Probe) • Mechano-Optical Probe (MOP) • Ultrasonic methods(non-invasive, but need contact) • Ultrasound Doppler Velocimetry (UDV) • Inductive methods(contact-less) • Inductive Flowmeter (IFM) • Contactless Inductive Flow Tomography (CIFT) • X-ray radioscopy

  7. Ultrasound Doppler Velocimetry (UDV) • Takeda (1987, 1991) • Commercial instrument • standard transducers (Tmax = 150°C) • Measurement of instantaneous velocity profiles

  8. UDV in liquid metals – problems • High temperature • Acoustic coupling • Transmission of ultrasonic energy through interfaces (channel walls) • Wetting conditions • Availability of reflecting particles

  9. Concept of an integrated probe I

  10. Concept of an integrated probe II • Collaboration with the University Nishni-Novgorod (Russia) • Piezoelectrictransducer coupled on an acoustic wave guide made of stainless steel • Stainless steel foil (0.1 mm) wrapped axially around a capillary tube: length 200 mm, outer diameter 7.5 mm

  11. UDV – Flows driven by RMF/TMF

  12. UDV – Flow driven by RMF Streamfunction Vertical velocity

  13. UDV – Flow driven by TMF Vertical velocity Streamfunction

  14. UDV – Flow driven by RMF/TMF

  15. UDV in CuSn/Al – Experimental Set-up • Rectangular alumina crucible (130  80 mm2) • melt depth 40 mm • inductive heater • melt temperature: 620°C (CuSn), 750°C (Al) • installation of the integrated sensor at the free surface of the melt • Doppler angle 35°

  16. UDV in CuSn/Al – Results Profiles obtained at two positions: • different signs • similarity of shape and amplitude Velocity signal obtained in liquid aluminium by up-and-down moving of the sensor by hand

  17. Contactless Inductive Flow Tomography (CIFT) • An existing flow field will modify an applied magnetic field: B=B0+b,b~Rm B0 (Rm=µLv) e.g. the magnetic field measured outside the melt contains information about the flow field • Rm ~ 10-3  b ~ O(T) Example: crystal growth configuration (Czochralski method)

  18. CIFT - Basics • Bio-Savart‘s law • inverse method to reconstruct the velocity field • additional requirements: • mass conservation (div u = 0) • Tichonov regularization (keeps the mean quadratic curvature of the velocity field finite)

  19. CIFT - Experiment • 48 Hall sensors (KSY44-Infineon, resolution 1 T) • Mechanical stirrer (2000rpm) max. velocity ~ 1 m/s • Cylinder filled with InGaSn (D = 180 mm , H = 180 mm) • Magnetic field: two pairs of Helmholtz coils 10mT

  20. CIFT - Experiment Lid with stirrer and motor Vessel, electronic equipment

  21. CIFT - Results Induced magnetic field for transverse primary field Induced magnetic field for axial primary field Reconstructed velocity field

  22. CIFT - Results

  23. Conclusions • Several measuring techniques exist to determine the velocity field in metallic melts • Successful investigations are under progress to extend the application range towards higher temperatures • Promising new developments: • Ultrasound Doppler Velocimetry (UDV) • Contactless Inductive Flow Tomography (CIFT)

More Related