Hydrodynamic Design of Francis Turbine Runner

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Hydrodynamic Design of Francis Turbine Runner

• P M V Subbarao
• Professor
• Mechanical Engineering Department

Provision of Features to Efficient Benign
Muscle.
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Environment Friendly Runner

• The issue of safe fish passage dominating the
  decision of whether a new generation turbine
  design concept is environmentally friendly.
• Fish passage is an important issue to many
  hydroelectric plants operations.
• Biological design criteria are needed to assist
  in establishing allowable limits of hydraulic
  parameters that may contribute to fish mortality
  and plant operation.
• Injury and mortality mechanisms are dependent on
  the zone which the fish takes to pass through the
  turbine system.
• At Wanapum Dam in Washington, fish that passed
  through a zone near the turbine hub experienced
  5 higher mortality than fish that passed through
  the zone in the middle of the runner.

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• Injuries caused by pressure appear to be related
  to the difference between the acclimation
  pressure upstream of the turbine and the exit
  pressure within the draft tube zone.
• A threshold value of the shear stress indicator
  was identified as 135 m/s/m.
• Values above this rate are believed to cause
  mortality .
• Turbines can be designed to operate cavitation
  free while increasing power production. Proper
  turbine operation at cavitation-free conditions
  will reduce maintenance costs and fish mortality
  that is believed to be related to cavitation.
• Tests at Wanapum Dam showed that peak fish
  survival did not coincide with peak efficiency

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Fish Injury Mechanisms
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Fish Friendly Runner
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Shape of Francis Channel Meridional Plan
Rr1e
Rr2i
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Real values of Radii
The real value of the outlet tip radius
The real value of the intlet root radius
Rr2e and Rr1i are only fix two points of the
leading and trailing edges and the rest of these
curves should be drawn to lead to better
efficiency of runner.
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Determination of Inlet exit edges runner
The form of these edges is two parabolic curves.
1i
Define the non-dimensional specific speed
1e
2i
For
2e
the leading edge form is a parabolic arc with the
peak in the point by radius of 2.Rr1i-Rr2iwhich
passes through the points 1i and 2i,
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1i
and for specific speeds between
1e
its form is also a parabolic arc but with the
minimum point in the 1i and the axis is parallel
to runner axis.
2i
2e
In the exit area, trailing edge is a parabolic
curve which has a minimum point in 1e and also
passes through a point such as 2i with a radius
of Rr1i/3.
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Dimensions of Runner Channel Meridional Plan

• The BOVET well known relations give the geometry
  of hub and shroud curves in the runner blade
  zone.
• The form of limit curves is defined by equation

Rr1e
Rr2i
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Location of Runner Vane in Runner Channel
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Variation of Flow Velocity
Vf
s
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Perpendicular Plan Conservation of Rothalpy