Computer support of design activities within precision devices speeds up achieving proper technical solutions, makes documentation to be developed more easily and reduces risk of making errors. Computer simulation of operation of devices being designed plays a significant role in this process. Besides performance characteristics of the device determined this way it also seems to be important to predict analytically other kinds of product characteristics i.e. reliability and availability. A concept of modelling of electrical drive systems for precision devices, verified along the years there is presented in the paper. It seems to be convenient from the point of view of designer. A proposal to utilise simulation results for better prediction of the device reliability is added. and Obsahuje seznam literatury
The paper deals with a modeling of a flow in hydraulic parts of a turbo machine operating in a pump and in a turbine mode. The results are Q-H (Q-Y) performance characteristics of the pump operating in both modes. An important piece of knowledge is a shift of the pump‘s and turbine‘s BEP and the change of specific speeds of the turbo machine in a pump and in a turbine mode, which emerges from it. The goal of this paper was to find a shift of pump‘s and turbine‘s BEP and to obtain information about hydraulic efficiency of the pump operating in a pump and turbine mode. Anyway the aim of CFD simulation is to evaluate Q-H (Q-Y) characteristic from the point of view of a stability of Q-H curve. The analysis of flow patterns in the impeller and in the vane diffuser in a pump and turbine mode is a valuable contribution to the topic of a hydraulic interaction between an impeller and a vane diffuser. and Obsahuje seznam literatury