Dam outlet works using a link-sleeve valve with air aspiration

Abstract

Air entrainment of a water discharge from a link-sleeve valve (LSV) was investigated with its application to the dam outlet works in mind. For large head discharge in order to prevent cavitation erosion, vibration, and noise, air must be injected into the downstream pipe to recover the pressure. However, the appropriate rate of air injection is certain only for the jet flow gate valves (JFG) now widely in use. We investigated experimentally the air suction characteristics of an LSV and found that there is a close analogy with a jet pump or an ejector. Present findings could be useful for improving the potential use of LSV as a more low-maintenance alternative to the JFG.