This study quantifies the influence of debris cages on critical submergence at vertical intakes in reservoir configurations. Four model debris cages were constructed of light panel material. A vertical intake protruding one pipe diameter above the floor of a model reservoir was tested in six configurations: open intake pipe, a debris grate placed directly over the intake pipe, and debris cages representing widths of 1.5*d and 2*d and heights of 1.5*c and 2*c, where d is diameter of the intake and c is height of intake above reservoir floor. A selection of top grating configurations and a submerged raft configuration were also tested for comparison.
Testing of the model debris cages indicates that the roof or top grate of a debris cage dominates the influence a debris cage has on the reduction of critical submergence of air-core vortices. The side grates of a debris cage have some influence on the formation of vortices. The spacing of bars in the top grate has an influence on air-core vortex development.
The presence of a debris cage at vertical intakes in still-water reservoirs reduces the critical submergence required to avoid air-core vortices and completely eliminates the air-core vortex for cases where the water surface elevation remains above the top grate of the debris cage. The potential exists for designing debris cages to fulfill a secondary function of air-core vortex suppression.
| Identifer | oai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-1119 |
| Date | 01 December 2008 |
| Creators | Allen, Skyler D |
| Publisher | DigitalCommons@USU |
| Source Sets | Utah State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | All Graduate Theses and Dissertations |
| Rights | Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact Andrew Wesolek (andrew.wesolek@usu.edu). |
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