Francis Turbines
Noelle Fillo, Kimberly Fridsma, Callen
Hecker
History
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Developed by James B. Francis in
Lowell, Massachusetts
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Founded ASCE
Locks and Canals company
1848
The first Francis turbine was
housed in the Pawtucket
Gatehouse in Lowell, MA.
He based his designs off of other
turbines that were designed around
that time.
Pawtucket Gatehouse
http://iopscience.iop.org/article/10.1088/1755-1315/22/1/012020/pdf, https://en.wikipedia.org/wiki/Francis_turbine
History
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Design based off of Benoit Foureyron’s outwardflow turbine and Jean-Victor Poncelet’s inwardflow turbine.
Can be used in a variety of hydraulic heads and
flow levels
Francis Turbines are a reaction turbine
First hydraulic turbine with radial inflow
https://en.wikipedia.org/wiki/Francis_turbine, http://turbinegenerator.org/hydro/hydropower-types/francis-turbine,
http://www.brighthubengineering.com/fluid-mechanics-hydraulics/27407-hydraulic-turbines-francis-turbine/,
History
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Many different design changes
over the years from 1848 to
1920.
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First stock turbine
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Newer designs included
adjustable guide vanes
http://iopscience.iop.org/article/10.1088/1755-1315/22/1/012020/pdf
Elevation and Plan View of a Francis turbine
http://hopshop.net/tours/electricutility/images/francis-turbine.jpg
http://www.bflhydro.com/img/img-modal-francis.jpg
The Physics of a Francis Turbine
https://www.youtube.com/watch?v=3BCiFeykRzo
Physics Cont.
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Water flows through spiral
casing, runners, guide
vanes and exits out turbine
eye
Pressure differences
caused by blade shape
allow for rotation and
draws water towards
center
Guide vane angles are
manipulated to optimize
flow
CFD images showing high velocities near
eye and blade edges
http://www.cfdsupport.com/water-turbine-cfdmanual/francis-turbine-cfd-openfoam-rotorresults-velocity-1.png
http://www.e3k.com/images/CFDfrancis02.png
Preventing Cavitation
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Pressure differences caused by flow create
vortices that damage surfaces
Indicated by a popping noise
Static pressure must not go below vapor
pressure
Flow separation at turbine exit must be
avoided to avoid draft tube damage
Must control for:
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Pressure head
Flow rate
Exit Pressure
Advantages of Francis Turbines
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Francis turbines work best for medium to
high range heads
Easily controlled operating head
Francis turbines operate over the largest
range for both flow and head parameters
Large range in size to meet different
power requirements
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Range from 0.25 MW to 1000 MW
High efficiency
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Generally around 94%
Operative ranges of different turbines
http://www.gunt.
de/networks/gunt/sites/s1/mmcontent/produktbilder/07036531/Datenblatt/07036531%202.
pdf
Advantages
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Francis turbines are mixed flow designs
Francis turbines have the highest
maximum power for turbines
Francis vs. Pelton
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Smaller and more economical than a
Pelton wheel capable of the same
power generation
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More resistant to wear than the
Pelton wheel
○ Francis turbines have higher levels
of efficiency
http://www.gunt.
de/networks/gunt/sites/s1/mmcontent/produktbilder/07036531/Datenblatt/07036531%202.
pdf
Disadvantages
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Unclean water can cause rapid wear in
Francis turbines
Cavitation is always a possibility
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Runner erosion
Losses in efficiency
Effects of cavitation on runner
http://authors.library.caltech.edu/25019/1/chap6.htm
Difficult to maintain and clean
Low acceptance of head variation
Constant adjustment of guide vanes and
runners
Francis turbines are generally limited to
large hydroelectric systems
Possible cavitation areas on the runner
http://www.diva-portal.org/smash/get/diva2:741702/FULLTEXT01.pdf
Disadvantages
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Francis turbine efficiency significantly
decreases with turbine flow rates below
40%
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Decreased flow also greatly increases
cavitation risk
Water hammer effect can cause harmful
effects
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Occurs when runners are forced from high
speed to stopping
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Build up of overpressures can cause
catastrophic results
http://www.esru.strath.ac.uk/EandE/Web_sites/01-02/RE_transmission/index.htm
http://www.plumbingmart.com/water-hammer-information.html
Calculations/Relevant Equations
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Blade Velocity
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Guide vane angle
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Power Generated
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Specific Speed
Example
A Francis turbine is to be operated at a speed of 600 rpm and with a discharge of
4.0 m3/s. If r1 = 0.60 m, β1 = 110⁰, and the blade height B is 10 cm, what should
be the guide vane angle α1 for a nonseparating flow condition at the runner
entrance?
Case Study I- Itaipu Dam in Brazil/Paraguay
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Located on the Parana River between
Brazil and Paraguay
One of the Seven Wonders of the Modern
World
Second largest hydroelectric power plant
87.8 TWh generated in 2014
118m of hydraulic head
20 Francis turbines
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700 MW each
16 m diameter
Average reservoir capacity
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19x109 m3
http://www.solar.coppe.ufrj.br/itaipu.html
Case Study II- Guri Hydroelectric Power
Plant in Orinoco, Venezuela
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On the Caroni River in Necuima
Canyon in Orioco, Venezuela
Installed capacity of 10,200 MW
and provides 12,900 GW/h to the
country
Ten 730MW Francis Turbines
Third largest power plant in the
world
http://www.power-technology.com/projects/gurihydroelectric/, http://www.industcards.com/hydro-venezuela.htm,
Case Study III- Vertical Twin Turbines in
Australian Irrigation Dams
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Used in Wyangala, Copeton and
Burrendong irrigation dams
Smaller turbines, but useful for
privately developed hydro schemes
Desirable when head is too high for
a Kaplan turbine
Ideal when:
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13 MW
45 m head
High efficiency and low prices
http://www.bryanleyland.co.
nz/uploads/2/9/7/1/29710909/twinfrancisturbines
.pdf
Fish-Friendly Francis Turbine Design
Do not allow cavitation to occur
Direct migratory fish away from
turbines
● Low number of blades with thick
edges
● Wide wicket gate-runner gaps,
● Wicket gates aligned with stay vanes
● Smooth surfaces provided
● Use advanced control system and
monitor speeds
● Minimize pressure changes
experienced by fish
http://www1.eere.energy.
http://www.westcoast.fisheries.noaa.
gov/wind/pdfs/doewater-13741.
gov/images/hydropower/newandoldturbinedesign_102313.gif
pdf
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Conclusions
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Francis turbines are one of the
most widely used turbines of our
time
Extremely high efficiency at
specific flows
Come in many sizes and are very
versatile
Large range of power outputs
Wanted when dealing with
relatively medium head and high
flows
https://i.ytimg.com/vi/0-sfeSq1IWs/maxresdefault.jpg