Performance Prediction of Eddy Current Flowmeter for Sodium
Sodium is used as a coolant in Fast Breeder Reactors. Eddy Current Flowmeter (ECFM) is used for measurement of sodium flow in the primary pump and at the outlet of the subassemblies. Eddy Current Flowmeter (ECFM) works on the principle of change in the magnetic field profile due to induced eddy currents as a result of sodium flow. It consists of a central primary winding, energized from an A.C. source, flanked on either side by two identical secondary windings connected differentially. The two secondary windings are balanced so that the output is nominally zero when the flowmeter is immersed in static sodium. The flow of sodium distorts the external field so that the electromotive forces generated in two windings differ by a magnitude proportional to the sodium velocity. ECFM is having axi-symmetric structure so a 2-D Axi-symmetric model has been used. In order to have coupling between the electromagnetic field and the fluid flow, two modules namely- AC/DC Azimuthal Induction Currents and Fluid Mechanics- Incompressible Navier Stokes have been utilized. The model developed using COMSOL has been validated against experimental results and a close agreement has been found. The developed model can lead to reduction in experiments required for calibration of the sensor.