Kort nozzle

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Flow conditions at a Kort nozzle (schematic)

A Kort nozzle is a conically tapered, airfoil- like profile FOURTH ring the propeller of a ship surrounding and in the 1930s by the Italian aeronautical engineer Luigi Stipa and the German shipbuilding engineer Ludwig Kort was developed. In contrast, a ducted propeller has a cylindrical jacket and is mainly used on aircraft .

By using a Kort nozzle, the flow losses at the ends of the propeller blades are reduced and a higher mass flow is generated. This leads to an increase in efficiency . Due to the calmer wake, the banks and beds of inland waters are less affected.

Kort nozzles are often used on tugs and barges . They can be rotated and thus used directly as oars . In recreational boating, Kort nozzles are often used to protect the propeller against damage from floating debris . In these cases the hydrodynamic effect is only slightly pronounced.

gallery

  • Kort nozzle at the stern of a tractor (propeller dismantled)

  • Rigid Kort nozzle

See also

literature

  • W. Beitz, K.-H. Küttner: Dubbel paperback for mechanical engineering . Springer Verlag, 1990. ISBN 3-540-52381-2