Design of a Kaplan hydraulic turbine Report

Pagina 1

Design of a Kaplan hydraulic turbine 1 Contents 1 Introduction 3 2 Initial data 3 3 Wicket gates design 5 4 Rotor design 7 5 Losses 9 5.1 Rotor losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.2 Wicket gates-rotor passage loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.3 Draft tube loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6 Cavitation check 10 2 1 Introduction The aim of the project is to design a Kaplan Turbine for a small hydro-power plant. In particular we start to design the wicket gates, and later we pass to the rotor study. We’ll compute the losses in the whole plant: radial gap between stator and rotor, runner, draft tube losses and kinetic energy lost. At the end it’s evaluated an overall estimation of the efficiency. 2 Initial data The starting design data are defined by the characterics of the plant which are listed in the following table: Hm [m] Q [m3/s] Pole pair [-] n [RPM] ws [-] η [%] 12 10 14 215 2.1 86 Table 1: data input The number of poles is selected to have a reasonable value of the specific speed on the Baljieu diagram and to obtain a reasonable distribution of the velocity triangles. Figure 1: Banjle diagram Once the initial data have been selected is possible to determine some geometric features of the machine throughout the help of statistical diagram. In particular it is possible to estimate the power produced by the efficiency introduced before: P =ρgHmQη (1) and converting the power from W to Hp is possible to derive the characteristic speed: nc =n √ P Hm 5/4 (2) By knowing this parameters is possible then to obtain the height of the wicket gates and the internal diameter of the runner. The geometric ratio B/D1e and DM/D1e are found. 3 Figure…