Height of fall (hydraulic engineering)

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The term drop height from hydraulic engineering refers to the difference between the upper and lower water levels of a drop , specifically for example a weir , a lock or a hydroelectric power station . In technical terms, it is the vertical height difference between the reference horizons that is important for the use of hydropower, regardless of the type.

Height of fall of the Rothensee lock , recognizable by the lock wall

Fall height of a ship lock

In the case of ship locks , the height of fall denotes the mean value of the difference in height between the upper water above sea ​​level and the lower water level of the lock above sea level.

Construction head

The design head designates the original height difference for which a turbine was designed. This is the smallest head at which the expansion flow can just be processed. A turbine is designed for a certain absorption capacity and a certain head. These values ​​can be found in the data sheet of the turbine. However, it can also be operated under different head conditions within certain limits.
In general usage, the height of fall is the raw or gross head of fall . This results from the difference in height between the upper and lower water level in the case of overpressure turbines or the mean value of the contact points between the jet axes and the jet circle diameter in the case of Pelton turbines . The resulting useful head or net head, on the other hand, forms the difference in energy levels between the inlet and outlet cross-sections of the turbine.
The net head thus takes into account the friction and shape losses in the penstock lines of high pressure systems as well as the inlet losses at the penstock intake.
Since the energy yield of a hydropower plant essentially depends on the inflow and the net head, the term head has a special meaning.
The term slope is also often used for height of fall .

See also

literature

  • DIN 4047-5 Agricultural water, terms, development and maintenance of waters, March 1989
  • DIN 4048-2 Hydraulic engineering, terms, hydropower plants, July 1994

Individual evidence

  1. ↑ DIN 4054 hydraulic engineering, terms, September 1977.
  2. ↑ Water management and general hydraulic engineering. (PDF) In: iwhw.boku.ac.at. P. 5 , accessed on October 9, 2016 .
  3. ^ J. Giesecke, E. Mosonyi: Hydropower plants, planning, construction and operation. Springer-Verlag, Berlin / Heidelberg / New York 2005, ISBN 3-540-25505-2 .
  4. ^ A b T. Strobl, F. Zunic: Hydraulic engineering, current basics-new developments. Springer-Verlag, Berlin / Heidelberg / New York 2006, ISBN 3-540-22300-2 .