Rehabilitation of Francis Turbines of Power Plants With Computational Methods

Abstract

Rehabilitation of existing hydroelectric power plants (HEPP) by redesigning the hydraulicturbines is usually more elaborate than designing a tailor-made turbine for a new plant.Some of the parts are buried and the space is limited with the size of the old turbine; therefore,this increases the number of constraints imposed on the design. This article presents aComputational Fluid Dynamics (CFD) based rehabilitation procedure involving the stateof the art redesign of the turbine of a hydroelectric power plant for better performance atdesign and off-design conditions of several head and flow rates. Runner and guide vanes ofthe Francis turbine are designed per the design head and flow rates available for the turbineat the site. The simulations for the designed parts are performed both separately and usingall turbine parts as full turbine analyses. Both the design and off-design conditions aresimulated for the newly designed and existing turbines for comparison purposes. Cavitationperformance of the new design is also determined. The proposed methodology is applicableto any Francis type turbine and any HEPP that needs rehabilitation.