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.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Ball, J. W. (1962). “Sudden enlargements in pipelines.”J. Power Div., ASCE, 98(4), 15–27.
2.
Ha, H. W., Wang, H. F., and Li, S. H. (1989). “Prototype experiment on two-stage orifice tunnel discharging water flow with sediments.”J. Hydr. Engrg., 7, 21–27 (in Chinese).
3.
Li, Z. Y. ( 1992). “A study on the orifice tunnel of Xiao Langdi Reservoir.” Res. Rep. No. HR(E)92-015, China Institute of Water Resources and Hydropower, Beijing (in Chinese).
4.
Tullis, J. P., and Govindarajan, R. (1973). “Cavitation and size scale effects for orifices.”J. Hydr. Div., ASCE, 99(3), 417–430.
5.
Wu, C. G. ( 1982). Hydraulics, People's Education Press, Beijing, 187–197 (in Chinese).
6.
Xu, F. S., Yu, M. X., and Liu, S. J. ( 1988). “Cavitation and fluctuating pressure of multi-stage orifices.” Adv. in Hydrodynamics, 3(3), 68–75 (in Chinese).
7.
Zhan, K. X. ( 1987). “Experimental study on orifice geometry and arrangement in a tunnel.” Discharge Engrg. and High Speed Flow, 2, 24–29 (in Chinese).
8.
Zhang, Z., and Cai, J. (1999). “Compromise orifice geometry to minimize pressure drop.”J. Hydr. Engrg., ASCE, 125(11), 1150–1153.
9.
Zhao, H. Q. ( 1993). “An experiment study on the energy dissipating coefficients of multi-stage orifices.” Water Resour. and Hydropower, 6, 24–33 (in Chinese).
Information & Authors
Information
Published In
History
Received: Mar 9, 2000
Published online: Aug 1, 2001
Published in print: Aug 2001
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.