Modelování proudění v hydrodynamickém čerpadle

Abstract

This thesis deals with numerical modelling of the flow inside the hydrodynamic pump with low specific speed. The geometry of the hydraulic parts was defined according to pump with the impeller that was designed at the Victor Kaplan Department of Fluid Engineering, Energy Institute, Technical University Brno. The main objective was to determine pump performance characteristics (variation of head, power consumption and efficiency on the flow rate) as well as radial and axial forces using computational fluid dynamics. Two approaches to rotor stator interaction were applied: Moving Reference Frame and Moving Mesh. The method MRF provides only stationary solution of values, but the Moving Mesh approach shows time variation of them and enables to account for interaction of impeller and volute. Different turbulence models and solution parameters were tested. The entire operating range from Q = 0 to Qmax considered in the design was investigated. Most of the calculation was performed on simplified geometry consisting only of three parts: intake, impeller and volute. In case of axial thrust prediction the geometry including also the pump casing was applied. The obtained results were compared with the experimental data and the theoretical assumptions. Both advantages and limitations of the numerical modelling are presented. The applied methods can be utilized as an appropriate approach to treat complex turbulent flow encountered in hydraulic machines.