Vyšetřování parametrů hydraulických strojů s využitím numerických metod

Abstract

This PhD thesis is focused on numerical modelling of the flow in hydrodynamic pump. In the introduction the state of the art is described and the equations describing a flow are given. Two different geometries of 40-NED-250-9 hydrodynamic pump were created. The first geometry contains only hydraulically active parts, like suction, impeller and volute. The second geometry contains also stator parts with sealing rings. With numerical modelling, the main characteristics of the pump were set and results were compared for both geometries with measured data. Both steady and unsteady flow in a pump was solved. These two approaches greatly differ one from another. From this reason the next comparison was done for these results. The amplitude and direction of the radial force was investigated using numerical modelling. The basic theory about radial forces is described. The results obtained with numerical modelling were compared with results calculated by means of empirical formulas that are presented in literature. Influence of the partial wettability of selected hydraulic parts on the pump performance was investigated. For this purpose, wall boundary condition was modified through the user defined function to account for partial surface wettability by means of adhesion coefficient k. This boundary condition was applied on selected pars of hydrodynamic pump for investigation of changes in pump parameters.