Model Investigation of Intake-Shoaling and Pump-Vibration Problems: Iowa Generation Council Bluffs Unit 3 Circulating-Water Intake

摘要

Iowa Generation's Council Bluffs Unit-3 cooling-water pump-intake structure, located along the concave bank of the Missouri River bend near Council Bluffs, Iowa, has been experiencing two chronic problems: (1) heavy sediment deposition outside the trash racks as well as within the intake bays; and (2) severe pump-vibration problems and accelerated wear of pump bearings. On the basis of the diagnostic field data collected, two hydraulic models were constructed and used to resolve the shoaling and pump-vibration problems. A 1:36-scale, undistorted, movable-bed model was utilized to investigate the effectiveness of turning vanes in producing a scour trench in front of the intake. A 1:12-scale, undistorted, rigid-boundary model then was used to achieve improvements in the pump-approach-flow distributions and elimination of free-surface and boundary-attached vortices by means of baffle walls, flow-turning vanes, horizontal gratings, and vortex splitters.