EFFECT OF GEOMETRICAL PARAMETERS OF PUMP-TURBINE RUNNERS ON ENERGY CHARACTERISTICS

The paper presents the results of design, numerical, and experimental studies of models of pump-turbine flow passages for heads up to 200 m. The task was to improve the performance of the ORO170/5217 pump-turbine, which is successfully operated at 1-4 power units of the Dniester PSP. Using the software developed at IPMach, a series of runners was designed to determine the effect of the number of blades on the power characteristics in turbine and pump modes. Using the proprietary IPMFlow software package developed at IPMach, preliminary numerical studies of the flow process in the turbine mode were carried out. Numerical modeling of the incompressible viscous fluid flow was performed by numerical integration of the Reynolds-averaged Navier-Stokes equations using artificial compressibility. The equations of fluid motion were supplemented by the differential two-parameter Menter SST model. The equations were integrated using the implicit quasi-monotonic Godunov scheme with second order approximation in space and time. The flow structure and energy performance of the new runners were compared with those of R5217. Selective experimental studies of pump-turbine models were carried out on the ECS-30 hydrodynamic test rig at IPMach. The test rig has no analogues in Ukraine, it is equipped with state-of-the-art devices and a set of measuring instruments, the performance of which meets the requirements of the international energy standard IEC 60193. In order to significantly reduce the research cost and time, the runner blades were manufactured using 3D printing technology from PLA plastic. The energy characteristics in turbine and pump modes were obtained. It was determined that in the turbine mode, the model with 7 blades is the most efficient in almost the entire range of operation at the plant – at the nominal head, its maximum efficiency is more than 2.5% higher than that of the original version. The geometric data of this runner was transferred to JSC “UKRENERGYMACHINES” for implementation in the project for the development of 5-7 hydraulic units of the Dniester PSP.