Conception et construction des turbomachines hydrauliques de grandes dimensions

The Francis Turbine: Analysis of Its Evolution

“…In a hydraulic machine, the flux which has interchanged energy does not change its density (and volume) when it is processed by the machine, in comparison to a thermal machine in which there is variation. This characterisation helps to classify machines, because the compressibility of the solid, liquid or gas will produce an equivalence in terms of thermal or hydraulic machines 4 .…”

“…This correlation is reinforced by previous researchers [2,3] Other studies have analysed this issue by focusing on turbine production during the latter half of the 20 th century, and have concluded that specific speeds (Ns) incur measurable changes at higher falls but not at low falls. In this regard, previous researchers [4,6] analysed the Francis Turbine and the progress of specific speed. According to previous and current analyses , during the forties, the component H-Ns was high in low drop waterfall harnesses.…”

“…Since then, efficiency has not varied greatly, and improvements have been relatively small. In 1920, Francis Turbines 4 When the flux is incompressible it will be referred to another machine 5 See [8] for the role played by the condenser in the Combe steam engine. 6 There were further modifications, which took place mainly in factories where it was possible to reproduce them on a larger scale.…”

“…Previous studies have focused on the evolution of the turbine from the perspective of specific speed (N s ), as this was a key factor in the understanding of turbine performance. Other analyses have focused on the MPMI [4,5,6,7] by examination of how N s has co-evolved with the turbine industry. In order to understand the structure of technological changes in products, such as hydraulic machines, it must be determined whether such a change occurred as a result of the design process or whether the evolution of turbines as induced by changes in the MPMI itself.…”