DESIGN OF HIGH HEAD RUNNERS OF FRANSIC TURBINES

The energy characteristics of the hydroturbine, reflecting the total effect of the interaction of the flow with the working bodies, allow us to judge the operation of the machine as a whole. Information about the energy qualities of individual elements of the flow space is provided by the energy balance. Using the data of the energy balance, it is possible to identify the most favorable conditions for the joint operation of the elements of the flow space, that is, to achieve their agreement to increase the level of efficiency – the most important energy indicator of the hydroturbine. In order to improve the energy performance of the designed hydroturbine, various analyzes are conducted, that is, the dependence of the kinematic and energy characteristics of the hydroturbine on its geometric parameters is investigated. Such an analysis is carried out to find the most rational options for the flow space. The paper presents the design of the flow space of the high head hydroturbine FR400, performed with the help of programs developed at the department "Hydraulic machines named after G. F. Proskura". The method of energy characteristics analysis, based on the application of dimensionless parameters, is described. To improve the energy indicators at the preliminary stage of the hydro turbine design, multivariate calculations of the influence of the geometric indicators of the runner on the formation of the energy indicators of the hydroturbine are carried out. To substantiate and analyze the results, a predictive universal characteristic of the hydroturbine is built. To analyze the formation of energy characteristics of hydroturbines, the general kinematic properties of spatial lattices, as well as the general regularities of the interaction of the fluid flow with the runner, were used. The analysis of energy losses in the flow space of the high head turbine Francis: the spiral case, the guide vane, the runner and the draft tube at the optimal operating mode of the hydroturbine, as well as the analysis of the effect of the geometric elements of the runner on the changes in energy losses in the flow space, was performed. The given results of the calculation study confirm that in order to increase the level of efficiency, while maintaining the indicators of the optimal mode, it is necessary to change both the position of the starting edge of the impeller and the law of the distribution of angles along it.