Electromagnetic sensor for the detection of liquid and gas movement induced by ascending bubbles in liquid metal

The movement of opaque, electrically conducting liquids (here liquid metal), particulary in small diameter vertical tubes with gas injection (e. g. airlift pumps) has to be measured without sensors intruding into the tube's cross section. An electromagnetic velocity sensing setup using wall electrodes in a mercury column with rising argon bubbles is investigated. The bubble and the liquid metal movements (value and direction) are determined from the electrode voltage signal and the gas injection flow rate.