Experimental Study on Wave Propagation Behavior on Free Surface of Lithium Flow for IFMIF

Abstract

Velocity measurement of surface waves on high-speed liquid lithium (Li) flow was conducted by using the Li circulation loop at Osaka University to support target monitor and diagnostics applications for the International Fusion Materials Irradiation Facility (IFMIF). Free surface shapes were recorded with a high-speed video camera, and surface waves were tracked with the statistical correlations of image intensity patterns over a velocity range of 5 to 15 m/s. As a result, the velocity distribution of surface waves was measured. The development of surface velocity beyond the nozzle edge was clearly measured. The velocity measurement by this method might suffer from some influence from stationary waves, which were generated by a damaged nozzle edge. The measured velocity in a region free from stationary waves was seen to exceed the mean flow velocity, probably due to two-dimensional regular waves. For this case, the measured velocity may consist of the advection velocity of the Li flow and the phase velocity of the wave. For an irregular wave region, the measured velocity was shown to be approximately the same as the mean flow velocity. The present flow velocity measurement can be used in the high-velocity range where random waves are generated.