Automation of the design of the impeller of a radial-axial hydraulic turbine

Abstract

The article describes approaches to the design of a vane system of radial-axial hydraulic turbines based on an automated design system developed at SPbPU using the Python programming language. The specified system currently includes the following modules: selection of the main parameters of the hydraulic turbine, construction of the meridional projection of the impeller, calculation of the potential flow and construction of the blade system of the radial-axial hydraulic turbine. The choice of the main parameters of the hydraulic turbine is based on the technique generally accepted in hydraulic turbine engineering, which has been digitized and introduced into the software package. The paper considers and analyzes different approaches to the design of the meridional bypasses of the flow path in the area of the impeller of a radial-axial hydraulic turbine, a comparison of the results of their construction using different methods is given. A technique that is most suitable for algorithmization in the software package based on the results of the analysis was selected. The construction of streamlines and the calculation of velocities along them are presented on the basis of the calculation of the potential flow in the meridian section. The design of the blade system of the hydraulic turbine was carried out by the method of solving the direct axisymmetric problem of the theory of hydraulic machines. As an example, a blade system of a radial-axial hydraulic turbine was designed for a head up to 75 meters, the initial parameters of which correspond to hydraulic turbines-analogues of similar speed. The designed hydro turbine was calculated in Ansys, and the results confirmed its excellent energy properties. It is planned to further develop the software package in terms of automatic construction of 3-dimensional solid models of the flow path, which can later be calculated by the methods of computational fluid dynamics and optimized to obtain hydraulic turbines with parameters corresponding to the current state of the art.