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Title: Turbulent Flow Effects on the Biological Performance of Hydro-Turbines

Abstract

The hydro-turbine industry uses Computational Fluid Dynamics (CFD) tools to predict the flow conditions as part of the design process for new and rehabilitated turbine units. Typically the hydraulic design process uses steady-state simulations based on Reynolds-Averaged Navier-Stokes (RANS) formulations for turbulence modeling because these methods are computationally efficient and work well to predict averaged hydraulic performance, e.g. power output, efficiency, etc. However, in view of the increasing emphasis on environmental concerns, such as fish passage, the consideration of the biological performance of hydro-turbines is also required in addition to hydraulic performance. This leads to the need to assess whether more realistic simulations of the turbine hydraulic environment -those that resolve unsteady turbulent eddies not captured in steady-state RANS computations- are needed to better predict the occurrence and extent of extreme flow conditions that could be important in the evaluation of fish injury and mortality risks. In the present work, we conduct unsteady, eddy-resolving CFD simulations on a Kaplan hydro-turbine at a normal operational discharge. The goal is to quantify the impact of turbulence conditions on both the hydraulic and biological performance of the unit. In order to achieve a high resolution of the incoming turbulent flow, Detached Eddy Simulationmore » (DES) turbulence model is used. These transient simulations are compared to RANS simulations to evaluate whether extreme hydraulic conditions are better captured with advanced eddy-resolving turbulence modeling techniques. The transient simulations of key quantities such as pressure and hydraulic shear flow that arise near the various components (e.g. wicket gates, stay vanes, runner blades) are then further analyzed to evaluate their impact on the statistics for the lowest absolute pressure (nadir pressures) and for the frequency of collisions that are known to cause mortal injury in fish passing through hydro-turbines.« less

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1156998
Report Number(s):
PNNL-SA-104873
WC0100000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Conference
Resource Relation:
Conference: HydroVision 2014:Energizing Innovation, July 22-24, 2014, Nashville, TN
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; hydropower; CFD; turbine; fish

Citation Formats

Richmond, Marshall C., and Romero Gomez, Pedro DJ. Turbulent Flow Effects on the Biological Performance of Hydro-Turbines. United States: N. p., 2014. Web.
Richmond, Marshall C., & Romero Gomez, Pedro DJ. Turbulent Flow Effects on the Biological Performance of Hydro-Turbines. United States.
Richmond, Marshall C., and Romero Gomez, Pedro DJ. 2014. "Turbulent Flow Effects on the Biological Performance of Hydro-Turbines". United States.
@article{osti_1156998,
title = {Turbulent Flow Effects on the Biological Performance of Hydro-Turbines},
author = {Richmond, Marshall C. and Romero Gomez, Pedro DJ},
abstractNote = {The hydro-turbine industry uses Computational Fluid Dynamics (CFD) tools to predict the flow conditions as part of the design process for new and rehabilitated turbine units. Typically the hydraulic design process uses steady-state simulations based on Reynolds-Averaged Navier-Stokes (RANS) formulations for turbulence modeling because these methods are computationally efficient and work well to predict averaged hydraulic performance, e.g. power output, efficiency, etc. However, in view of the increasing emphasis on environmental concerns, such as fish passage, the consideration of the biological performance of hydro-turbines is also required in addition to hydraulic performance. This leads to the need to assess whether more realistic simulations of the turbine hydraulic environment -those that resolve unsteady turbulent eddies not captured in steady-state RANS computations- are needed to better predict the occurrence and extent of extreme flow conditions that could be important in the evaluation of fish injury and mortality risks. In the present work, we conduct unsteady, eddy-resolving CFD simulations on a Kaplan hydro-turbine at a normal operational discharge. The goal is to quantify the impact of turbulence conditions on both the hydraulic and biological performance of the unit. In order to achieve a high resolution of the incoming turbulent flow, Detached Eddy Simulation (DES) turbulence model is used. These transient simulations are compared to RANS simulations to evaluate whether extreme hydraulic conditions are better captured with advanced eddy-resolving turbulence modeling techniques. The transient simulations of key quantities such as pressure and hydraulic shear flow that arise near the various components (e.g. wicket gates, stay vanes, runner blades) are then further analyzed to evaluate their impact on the statistics for the lowest absolute pressure (nadir pressures) and for the frequency of collisions that are known to cause mortal injury in fish passing through hydro-turbines.},
doi = {},
url = {https://www.osti.gov/biblio/1156998}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Aug 25 00:00:00 EDT 2014},
month = {Mon Aug 25 00:00:00 EDT 2014}
}

Conference:
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