Contact

Dr. Thomas Wondrak
Magnetohydrodynamics
t.wondrakAthzdr.de
Phone: +49 351 260 2489
Fax: +49 351 260 12489

Transient Eddy Current Flow Meter (TEC-FM)

HZDR has been working on the development of calibration-free, inductive velocity sensors for liquid metals for several years now. This type of sensor is called Transient Eddy Current Flow Meter (TEC-FM). Initially an external TEC-FM was developed to measure the velocity at the fluid boundary from the outside, without direct contact with the liquid metal. This sensor is especially useful for small or shallow pipe flows. In order to perform local velocity measurements in large pipes or liquid metal pools, an immersed version of the sensor has been developed, which is called ITEC-FM. It can be used for ambient temperatures up to 700 °C. Contrary to the most inductive flow rate sensors, the TEC-FM yields results that are independent of the electrical conductivity or temperature of the liquid metal and therefore, no calibration of the sensor is necessary.

Functional Principle

Although there are some major differences in the structure of the external and immersed TEC-FM, they use the same physical principles. The primary coil or coils are used to imprint an eddy current system into the liquid metal which it then advected with the flow. With the help of the secondary coils, the position of a distinctive point like the zero crossing or the pole of the magnetic field of the eddy current system is tracked and recorded. The flow velocity can then be obtained from the progression of the distinctive point.

Figure 1: Basic structure of the TEC-FM

Figure 2: Basic structure of the immersed TECFM

Application

With the external sensor it is not only possible to perform contactless measurements of the flow velocity of liquid metals, it is also possible to measure the translational or rotational speed of metallic solids almost instantaneously. The immersed TEC-FM can be used for velocity measurements in large pipe flows or liquid metal pools, for example in liquid metal cooled reactors. The sensors have been tested successfully in Galinstan(GaInSn), sodium and with rotating copper- and aluminium disks.

Cooperation

  • Commissariat à l’énergie atomique et aux énergies alternatives (CEA, Frankreich)

Publications


Contact

Dr. Thomas Wondrak
Magnetohydrodynamics
t.wondrakAthzdr.de
Phone: +49 351 260 2489
Fax: +49 351 260 12489