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Table 4.7.3
Summary of Forced Air Turbine Venting
Characteristic
Description
Targets
Low DO levels of the release waters commonly
associated with hydropower generation during strati-
fied periods and anoxic conditions.
Mode of action
Blowers or compressors are used to force air into
turbine water flow through passages to increase the
DO levels of the release waters.
Effectiveness
Large DO uptake values can be obtained by this
technique but are limited by TDG supersaturation.
Longevity
Based on the life of the turbine; years.
Negative features
Maintenance requirements for rotating machinery,
Power and space requirements in the powerhouse.
Reduction in turbine generating efficiency during
aeration and, consequently, the related revenues.
Possible nitrogen supersaturation.
Costs
Moderate depending on the complexity and size of the
forced air system.
Applicability to reservoirs
Applicable to hydropower projects that do not meet
objectives with turbine venting.
4.7.5 REFERENCES
Almquist, C. W., P. N. Hopping, and P. A. March, "Energy Losses Due to Air Admission in
Hydroturbines," Proceedings of the ASCE National Hydraulic Engineering Conference, Nashville,
TN, August 1991.
Bohac, C. E., Boyd, J. W., Harshbarger, E. D., and Lewis, A. R. 1983. "Techniques for Reaeration
of Hydropower Releases," Technical Report E-83-5, US Army Engineer Waterways Experiment
Station, Vicksburg, MS.
Buck, C. L., D. E. Miller, and A. R. Sheppard, "Prediction of Oxygen Uptake Capabilities in
Hydraulic Turbines Utilizing Draft Tube Aeration Systems," Research Paper, Alabama Power
Company, Environmental and Research Services, 1980.
4.7-10
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