Numerical study of the flow dynamics at no-load operation for a high head Francis turbine at model scale

[摘要] No-load operation is among the most damaging operating conditions. Since no energy is extracted by the turbine during this operation, the fluid energy is dissipated by highly energetic and turbulent flow phenomena causing high pressure and strain fluctuations on the turbine components. These highly turbulent flows are complex and, until now, poorly understood. This paper presents preliminary three-dimensional simulations of no-load turbulent flow within a high head Francis turbine at model scale using Computational Fluid Dynamics and the SAS-SST turbulence model. The numerical results are compared with unsteady experimental pressure data acquired on the runner blades of a model turbine. A preliminary study of the numerical results reveals some specific flow behaviors present at no-load operation.

[发布机构] LAMH, Mechanical Engineering Department, 1065 avenue de la médecine, Université Laval; QC; G1V 0A6, Canada^1;Andritz Hydro Canada Inc., 6100 Transcanada Highway, Pointe-Claire; QC; H9R 1B9, Canada^2

[关键词] Flow behaviors;Flow dynamics;No-load operations;Numerical results;Operating condition;SST turbulence models;Strain fluctuations;Three dimensional simulations