Experimental research of francis pump-turbines with splitters in a pump mode

The pathways of efficiency increase of pump-turbines are considered. It is revealed that one of the perspective ways is to use runners with additional shortened blades - splitters. The description and characteristics of the test stand in the laboratory of hydromachines of the A. Pidgorny Institute of mechanical engineering problems of the NAS of Ukraine (IPMash) and their compliance with the requirements of the International Standard for conducting research of hydraulic machines is presented. The description of methods of design and manufacture of four variants of runners with splitters with different lengths: 50, 65, 80 and 100% relative to the main blade is presented. For all variants of flow parts, experimental characteristics in pump mode were obtained and plotted. The influence of the splitter geometrical parameters on the values of maximum efficiency and the parameters of the optimum mode are revealed. The dependences of efficiency and head on the flow rate for all variants of runners with splitters at different values of the guide vane opening are given. The effect of splitter length on the energy characteristics of the pump-turbine in the pump mode is revealed. The comparison of energy and pressure characteristics of flow parts with seven- and eight-blade runners is given.