@article{Vasko_2021, title={APPROXIMATION OF UNIVERSAL CHARACTERISTICS OF HYDROTURBINES BY ENGINEERING GEOMETRY METHODS}, url={https://ve.org.ua/index.php/journal/article/view/310}, DOI={10.36296/1819-8058.2021.3(66).62-71}, abstractNote={<p><em>The application of engineering geometry methods for approximation of functional two-parameter dependences of universal characteristics of hydroturbines, which are a set of open and closed lines on the plane, which characterize the results of experimental studies of physical models of turbines, is tested.</em> <em>Universal characteristics are given in the nomenclature of hydroturbines and serve as initial information for a choice of parameters of full-scale samples and definition of modes of their effective operation.</em> <em>They allow you to calculate the diameter of the impeller to obtain a given power; nominal turbine speed; values coefficient of performance</em> <em>and allowable suction heights at all pressures and capacities; opening of the directing device for any loading of the turbine. Conducting multivariate computational research requires digital processing of the original graphical information and its further use, so the issues of approximation of curves and surfaces by cubic spline functions, graphical determination of surface maxima, graphical determination of surface cross section were considered. Methodical provisions for determining the energy-efficient mode of operation of propeller and radial-axial hydraulic turbines at variable water flow rates and speed have been developed. The provisions are based on the application of engineering geometry methods to approximate the universal characteristics of the turbine in the form of the surface of a three-dimensional geometric body and determine the surface maxima, which characterizes the optimal functional relationship between the opening of the guide and speed and provides maximum energy turbines. An algorithm for calculating the coefficients of approximation cubic spline functions of the universal characteristic of a hydroturbine for determining and implementing the laws of control of energy-efficient modes of operation of hydraulic units with simultaneous change of two control parameters is proposed. The algorithm consists in approximating the initial universal characteristic of the hydroturbine to a uniform grid of control parameters with the subsequent direct calculation of coefficients of spline functions on recurrent relations. </em><em>Bibl.</em><em>. 17, fig. 7.</em></p>}, number={3(66)}, journal={Vidnovluvana energetika}, author={Vasko, P.}, year={2021}, month={Sep.}, pages={62-71} }