Author(s): K. D. Nielsen; A. L. Davis
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Keywords: No Keywords
Abstract: The Four Dam Pool Power Agency operates a hydroelectric facility at Terror Lake which is located in a remote region near the City of Kodiak, Alaska. After some tunnel modifications, a 30 inch vent pipe located adjacent to the gatehouse at Terror Lake was observed spouting a mixture of air and water high into the air. According to observers, the geyser spouted for approximately 30 seconds followed by approximately 45 seconds with no air/water exhaust. The cyclic action was repeated several times before dying out. Damage from these events was limited to road erosion but there were concerns regarding the future effects of the violent air releases on the gatehouse structure and tunnel vent. A study was commissioned in 2004 to identify mechanisms that produced the geyser and to propose either operational or structural changes that would eliminate or minimize the problem. The study included the review of available air migration mechanisms and application of several predictive equations for air migration. In addition, a Computational Fluid Dynamics (CFD) model was developed to determine detailed hydraulics and perform air migration simulations. This paper presents a summary of the air migration mechanics, provides a comparison of air migration predictive equations, and illustrates the use of CFD simulations for analysis of air migration in closed conduit systems.
Year: 2009