89 research outputs found
Contactless Electromagnetic Phase-Shift Flowmeter for Liquid Metals
We present a concept and test results of an eddy-current flowmeter for liquid
metals. The flow rate is determined by applying a weak ac magnetic field to a
liquid metal flow and measuring the flow-induced phase disturbance in the
external electromagnetic field. The phase disturbance is found to be more
robust than that of the amplitude used in conventional eddy-current flowmeters.
The basic characteristics of this type of flowmeter are analysed using simple
theoretical models, where the flow is approximated by a solid body motion.
Design of such a flowmeter is presented and its test results reported.Comment: 19 pages, 13 figures, to appear in Meas. Sci. Technol (final version
Contactless inductive flow tomography
The three-dimensional velocity field of a propeller driven liquid metal flow
is reconstructed by a contactless inductive flow tomography (CIFT). The
underlying theory is presented within the framework of an integral equation
system that governs the magnetic field distribution in a moving electrically
conducting fluid. For small magnetic Reynolds numbers this integral equation
system can be cast into a linear inverse problem for the determination of the
velocity field from externally measured magnetic fields. A robust
reconstruction of the large scale velocity field is already achieved by
applying the external magnetic field alternately in two orthogonal directions
and measuring the corresponding sets of induced magnetic fields. Kelvin's
theorem is exploited to regularize the resulting velocity field by using the
kinetic energy of the flow as a regularizing functional. The results of the new
technique are shown to be in satisfactory agreement with ultrasonic
measurements.Comment: 9 Figures; to appear in Phys. Rev
Role of soft-iron impellers on the mode selection in the VKS dynamo experiment
A crucial point for the understanding of the von-K\'arm\'an-Sodium (VKS)
dynamo experiment is the influence of soft-iron impellers. We present numerical
simulations of a VKS-like dynamo with a localized permeability distribution
that resembles the shape of the flow driving impellers. It is shown that the
presence of soft-iron material essentially determines the dynamo process in the
VKS experiment. % An axisymmetric magnetic field mode can be explained by the
combined action of the soft-iron disk and a rather small -effect
parametrizing the induction effects of unresolved small scale flow
fluctuations
Annual Report 2010 - Institute of Safety Research
The Institute of Safety Research (ISR) was over the past 20 years one of the six Research Institutes of Forschungszentrum Dresden-Rossendorf e.V. (FZD), which in 2010 belonged to the Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz. Together with the Institutes of Radiochemistry and Radiation Physics, ISR implements the research programme âNuclear Safety Researchâ (NSR), which was during last years one of the three scientific programmes of FZD. NSR involves two main topics, i.e. âSafety Research for Radioactive Waste Disposalâ and âSafety Research for Nuclear Reactorsâ. The research of ISR aims at assessing and enhancing the safety of current and future reactors, the development of advanced simulation tools including their validation against experimental data, and the development of the appropriate measuring techniques for multi-phase flows and liquid metals
- âŠ