Hydraulic turbines

Overview

ABSTRACT

The various hydraulic turbines meet various functions which can serve as a basis for classification. The Pelton turbines are adapted to falls of more than 100 meters, with a maximum power of 350 MW. The Francis turbines are adapted to average falls of between 20 and 900 meters, with a maximum power of 1,000 MW. The Kaplan and propeller turbines operate under low falls of under 80 meters, with a maximum power of 400 MW. The bulb group turbines are adapted to low falls which are on average lower than for the Kaplan turbines and the bulb group turbines equip the pump storage power plants.

Read this article from a comprehensive knowledge base, updated and supplemented with articles reviewed by scientific committees.

Read the article

AUTHORS

Lucien MEGNINT: Arts et Manufactures engineer - Former Assistant Technical Director of Neyrpic
Georges VERDURAND: Arts et Manufactures engineer - Former Technical Director of Ateliers Bouvier (now Bouvier Hydro-Grenoble)
Robert REY: Arts et Métiers engineer - Professor, École Nationale Supérieure d'Arts et Métiers – CER Paris - This article has been revised and expanded by the last author.

INTRODUCTION

Except in special cases, a hydraulic turbine comprises the three characteristic components of turbomachinery: a distributor, the rotor and, if necessary, a diffuser.

It should be noted, however, that while action turbines have no diffuser, jet turbines do. It is used to recover a fraction of the kinetic energy at the impeller outlet and the geometric height between this outlet and the downstream level of the layout. By virtue of its function, it creates a vacuum at the impeller outlet and is therefore often referred to as an aspirator or suction pipe.

The different types of water turbines fulfil relatively precise functions, which can serve as a basis for a brief classification. Here are a few examples:

Pelton turbines suitable for falls of over 100 m, with a maximum possible power of 350 MW;
Francis turbines suitable for medium heads of between 20 and 900 m, with a maximum possible output of 1,000 MW;
Kaplan and propeller turbines operating at low heads, normally below 80 m, with a maximum possible output of 400 MW;
bulbous units, fully submerged, also suitable for low falls, but on average lower than Kaplan turbines (around 20 m maximum);
Turbine-pump units, reversible machines used in pumped storage power plants.