ICONE19-43535 COMPARISON OF THE WATER AND SODIUM CAVITATION PHENOMENA IN VENTURI

Abstract

The present paper described the comparison of onset cavitation coefficient and noise spectrum between water and sodium. The water experiment was conducted at 56°, 74° and 90℃. These temperatures corresponded to the same kinematic viscosity of sodium cavitation at 200°, 300° and 400℃. The test section used was a venturi with ID and OD of 6.5 mm and 21 mm, respectively. The results show that the onset of cavitation in water was influenced by dissolved oxygen (DO) concentration and temperature change. The increase of noise intensity in sodium was steeper as compared to water with higher DO, but it was relatively steep for lower DO. The onset cavitation coefficient of water was higher than in sodium, which could be caused by the relatively higher DO concentration due to higher solubility of air in water than argon in sodium. The dissolved air in water could increase the onset cavitation condition (coefficient) because gaseous cavitation was more dominance than vaporous cavitation. In both water and sodium, the increase of the noise spectrum in case of cavitation occurrences was higher for higher frequency region than at lower one which might be caused by the rapid formation and collapse of cavitation bubbles. From the numerical calculation, the results showed that temperature effect had large influence on the growth of the bubble.