Wasser in Pumpen und Turbinen
If one wants to approach the question of whether and in what way water is damaged by passing through turbines or pumps, one has first to get a clear and detailed picture of the flow conditions in these machines. This is what the present contribution intends to provide by comparing the water movements in hydraulic turbines and centrifugal pumps to those in a natural water course. It is shown that in the latter there is a great variety of different movements and rhythms with relatively small changes in the velocities and pressures. The movements in the turbines and pumps, however, are found to be extremely monotonous and rhythmless, but with strong variations of velocities, pressures and shear stresses concentrated in the runner of the machines. The water is here subject to movements based on purely technical and economic reasoning and it is to be expected that this reduces or even destroys its life supporting capabilities. This should to be investigated in a next step.