Approbation of an electromagnetic induction system for measuring the liquid metal velocity

Abstract

Two configurations of a transformer-based clamp-on induction system for velocity measurement were tested. One configuration provides information on the linear component of the liquid metal velocity, while the other – on the azimuthal component. The system was successfully tested on working media with different conductivities: solid duralumin, liquid gallium alloy, and liquid sodium. We studied the sensitivity and error of the measurement system as well as the effect of ambient temperature fluctuations and magnetic field drift on its transfer function. The achieved sensitivity is sufficient for signal recording by most modern digital voltmeters. Calibration of the clamp-on measurement system was carried out on the sodium test bench of the Scientific and Testing Center of Continuous Media Mechanics in the range of 0 – 4.42 m/s (0 – 120 m3/h). Magnetic field drift did not affect the linearity of the obtained calibration characteristic of the system. The final relative error was 6.5 % over the entire measurement range. The inline system is a virtually ready-to-use flowmeter for liquid metals. For industrial use, it only requires the addition of a protective thermal box with forced cooling. The clamp-on induction system for velocity measurement has proven effective and, in a rounded version, is already actively used, for example, in the ‘PIR’ correlation flowmeter.