Author(s): By John S. Gulliver; John Groeneveld; Guy E. Paul

Linked Author(s): John S. Gulliver

Keywords: No Keywords

Abstract: Spillway discharge at the Cabinet Gorge Hydroelectric Development has been shown to produce high total dissolved gas (TDG) concentrations in the tailwater of the spillway and the river reach downstream. As a part of their license renewal, Avista Corporation considered a Bypass Tunnel Project to pass the most frequent discharges that are currently passing over the spillway and avoid the most frequent high TDG concentrations in the tailwater. One challenge is that the rate of air entrainment has not been studied for this type of spillway or a large tunnel discharge. Our approach has been to take advantage of the pool below the spillway and tunnel, and assume that the air entrained into the pool by the spillway and tunnel is sufficient to develop a steady state concentration of TDG, such that additional air entrainment would not alter this concentration. The location of entrained air bubbles has been simulated with a computational fluid dynamics code. Gas transfer across the bubbles was then simulated with source/sink algorithms developed by the authors and applied to the bubbles. This paper will describe an assessment of the potential to reduce TDG concentrations through using the tunnels to bypass flows that otherwise would pass over the spillway.

DOI:

Year: 2009