Aial Flow turbine development for Ultra Low Head ….ppt

Recent approach to refurbishments of small hydro projects based on numerical flow analysis Virtual hydraulic laboratory, developed in collaboration with turbine manufacturer Why would older turbines need to be upgraded – would classical design methods be a reason ? Design based on CFD verification Practical methodology for an upgrade * byJacek SwiderskiSwiderski Engineering, Ottawa, Canada Study and analysis of the results allow developing an upgrade strategy Selected practical applications of Computational Fluid Dynamics (CFD) based on commercial CFX-TASCflow software package. Computational Fluid Dynamics (CFD) already established its strong presence in the hydropower industry as trusted engineering tool. (a)?Aerodynamics theories adequate for a very limited range of water turbines (compressibility) (b)??Existence of 3rd dimension component of the flow within the blade-to-blade space of a turbine runner (c) The upstream influence no classical, published design method takes it into account. ? Major design strategies exercised by the industry: ? A)? Classical design approach: (i) model tests– modifications (loop: lab-shop) (ii) CFD analysis-model tests–modifications (loop:CFD-lab-shop) B)??Newer approach – generic algorithms: model generation – CFD analysis – decision on shape modification (loop: CFD - Decision Program - CFD) ? C) Attempts to solve reverse problem: should there be a strict mathematical solution to the N-S equations, finding a shape of flow channel to achieve certain effect would be possible. 1)???? Numerical model – full geometry of the turbine including -????????? Intake -????????? Spiral casing -????????? Distributor (all stay vanes and wicket gates) -????????? Runner -????????? Draft tube 2)???? Tune-up of the numerical model -????????? Grid quality: verification and refinement. Based on couple of runs of the flow