Proceedings of The 20th Pacific Basin Nuclear Conference

Abstract

In this paper, cavitation phenomenon in the thin and long orifices were numerically studied. Thin and long orifices as a kind of throttling device have been widely applied in industrial production, especially as the letdown orifice in the RCV system of a nuclear power plant. First, the numerical model was established to simulate cavitation phenomenon in the orifice. Then, comparative analysis of different factors on the cavitation was carried out, including the influence of the back pressure, the inlet structure and the orifice length. Results show that cavitation in the orifices first occurs at the inlet of the orifice and then the cavitation area expands to the outlet with the decrease of the back pressure of the orifice. Changing the inlet structure from sharp edge to round edge and increasing the orifice length, can suppress the occurrence of the cavitation in the orifice.