부산대학교 도서관

Butterfly valves are widely used in water supply systems, sewage treatment plants, chemical processes, and the natural gas industry to control and regulate the flow of fluids. When the liquid medium flows through a butterfly valve, the local pressure decreases rapidly because of the sudden change in the flow channel area, which leads to the cavitation generated at the downstream of butterfly valve if the local pressure is lower than saturated vapor pressure. This cavitation negatively affects the performance of the valve, causing severe vibration and noise. In some cases, this may affect the sealing performance and lifetime of the valve and could even lead to accidents. This paper mainly carried out experimental studies on the cavitation phenomenon inside butterfly valves. The cavitation evolution was recorded inside the butterfly valve at different opening degrees and pressure conditions by a high-speed camera, and the pressure was monitored at upstream and downstream of valve plate. The influences of valve opening degree and total pressure on dynamic evolution and distribution of cavitation was revealed. By comparing the distribution of vortices and cavitation bubbles in the flow field, it was found that vortices led to the aggregation of cavitation bubbles and changed the distribution of these bubbles in the flow field. We also analyzed the interaction between the cavitation and the surface of the butterfly plate. The shedding of the attached cavitation was mainly caused by a reentrant jet. [ABSTRACT FROM AUTHOR]