Hydraulic Characteristics of Multistage Orifice Tunnels
Publication: Journal of Hydraulic Engineering
Volume 127, Issue 8
Abstract
In China many large-scale hydraulic projects have been designed with multistage orifice tunnels to dissipate a large amount of energy at the design discharge and water level. Based on two hydraulic-model tests and theoretical analysis about multistage orifice tunnels, this study further examined orifice geometry to meet energy-dissipation requirements and to minimize cavitation risk, as well as to systematically investigate factors influencing the energy dissipation and cavitation coefficients of the multistage orifices. The results indicate that measures, such as enlarging the tunnel diameter, decreasing the tunnel outlet area, and lowering the design water level of the reservoir, could be taken into consideration to increase the orifice cavitation coefficient σ for a given orifice geometry when the incipient cavitation coefficient σi of the orifice is large. For the same orifice contraction ratio β, the values of orifice dissipation coefficient k and σi are closely related to orifice geometry, especially to the radius r at the top edge of the orifice and to the ring fixed in front of the orifice plate.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 127 • Issue 8 • August 2001
Pages: 663 - 668
History
Received: Mar 9, 2000
Published online: Aug 1, 2001
Published in print: Aug 2001
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