Turbulent life of fish in turbines passages

How fish-friendly turbines work « Power Generation

That’s
why new fish-friendly turbine designs are a vital part of hydro’s
future. The U.S. Department of Energy’s Advanced Hydropower Turbine
System program has identified specific injury mechanisms, which include:

  • Turbulent
    flows or cavitation in turbine water passages resulting from
    low-efficiency designs or plant operating strategies where extremely
    low water pressures cause the formation of vapor bubbles, which
    subsequently collapse violently.
  • Turbulent
    flows and the trapping and cutting of fish in the zone of flow passing
    near the turbine hub when large gaps between blade and hub exist
    (characterizing the lower-output operation of Kaplan turbines).
  • Strike
    of fish by turbine blades or impact of fish on structures including
    runner blades, stay vanes, wicket gates, and draft tube piers.
  • Shear
    stress when two bodies of water of different velocities collide across
    a fish’s body. The highest values of shear stress are found close to
    the interface between the flow and solid objects it speeds by, such as
    the blade leading edges, vanes, and gates.
  • Rapid
    and extreme pressure changes (water pressures within the turbine may
    increase to several times atmospheric pressure, then drop to
    sub-atmospheric pressure, all in a matter of seconds).
  • Abrasion
    and grinding: Abrasion occurs with the rubbing action of a fish against
    rough turbine surfaces by flow turbulence and is dependent on flow
    discharge and velocity, number and spacing of turbine blades, and the
    geometry of flow passages. Grinding injury can occur when a fish is
    drawn into small clearances (gaps of sizes close to that of the fish)
    within the turbine system.

Cross-post from http://powergen.wordpress.com/2008/06/24/how-fish-friendly-turbines-work/

Maybe we could be of some help? Let’s find somebody interested in ‘fish-turbulence’ interactions.

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