Experimental study of bubble detection in liquid metal

R. Guichou¹ - P. Tordjeman¹ - W. Bergez¹ - R. Zamansky¹ - K. Paumel²

¹ Institut de Mécanique des Fluides de Toulouse (IMFT), Université de Toulouse, CNRS-INPT-UPS, Toulouse, France
² CEA, DEN, Cadarache, STCP/LIET, F13108 St Paul lez Durance, France

Abstract
Bubble detection in liquid metal is an important issue for various technological applications. For instance, in the framework of Sodium Fast Reactors design, the presence of gas in the sodium flow of the primary and secondary loops is an issue of crucial importance for safety and reliability. Here, the two main gas measurement methods in sodium are ultrasonic testing and eddy-current testing; we investigate the second method in our study. In a first approach, we have performed experiments with liquid metal galinstan containing insulating spherical beads of millimeter size. The liquid metal is probed with an Eddy-current Flowmeter (ECFM) in order to detect the beads and characterize their diameter and position. Results show that the signal measured by the ECFM is correlated with the effect of these parameters. Finally, an analytical model is proposed and compared to the experimental results. Figs 9, Refs 6.