Using mathematical modeling for determination the optimal geometric parameters of a pump-turbine water passage

Abstract

In this work, the method of non-dimension averaged parameters is applied. It allows to choose the optimal geometry of the elements of the water passage at the initial stages of designing a new reversible hydraulic machine or modernizing an existing one. This method has proved positive in the numerical study of high-head reversible hydraulic machines at pressures of 200 and 500 m. Using the method of non-dimension averaged parameters in calculation it is necessary to have geometric parameters only in the specific cross-sections of the water passage. This is very effective in terms of saving time and computational resources. In the course of the work, three variants of the water passage of the high-head low-speed reversible ORO500 hydraulic machine were investigated. As a result, it was determined that the geometry of the water passage's elements significantly effects the hydraulic machine's parameters. The highest losses value (62 %) is in the inlet (spiral casing with stator and wicket gate). Therefore, the parameters of these elements were changed. Hydraulic efficiency increased by 1.16 % results from changing the parameters of the spiral casing (increasing the average flow angle by 100). Changing the geometry of the wicket gate leads to additional increasing of efficiency by 0.84 %.