Characteristics of Cavitation and Erosion Phenomena in Sodium Flow

Abstract

This paper presents experimental data of cavitation experiments to determine the characteristics of cavitation and erosion in the flowing liquid sodium at 200–400°C. The test section is a venturi made from SUS316 since this material is used as the cladding material for SFR. The ID and OD of the venturi test section are 6.5 mm and 21.4 mm, respectively. The data show that the onset cavitation conditions (onset velocities) in liquid sodium are influenced by the change of the stagnant pressure at the expansion tank. Cavitation noise signals at developed cavitation conditions are not affected by the change of stagnant pressure and might be caused by choking of the sodium flow that restricts the formation of cavitation bubbles. For all the different stagnant pressures and temperatures, the onset cavitation coefficient K is around unity. Meanwhile, erosion experiment in the flowing liquid sodium for 600 hours at 200°C and cavitation coefficient value K of 0.59–0.51 (developed cavitation condition) reveals that cavity bubbles produce some micro pits at the outlet of the venturi test section. These pits indicate that erosion is occurred on the surface of the tested material and could be a major problem for the development of SFR if cavitation occurs inside the critical/important parts.