Second Oxford Tidal stream Workshop 2013 Are Nearly all Tidal Stream Turbines Designs Wrong? Stephen...
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Second Oxford Tidal stream Workshop 2013 Are Nearly all Tidal Stream Turbines Designs Wrong? Stephen Salter Institute for Energy Systems University of Edinburgh [email protected] www.see.ed.ac.uk/~shs [email protected] .uk [email protected] .uk
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Transcript of Second Oxford Tidal stream Workshop 2013 Are Nearly all Tidal Stream Turbines Designs Wrong? Stephen...
Second Oxford Tidal stream Workshop 2013
Are Nearly all Tidal Stream Turbines Designs Wrong?
Stephen Salter
Institute for Energy Systems
University of Edinburgh
www.see.ed.ac.uk/~shs
[email protected]@ed.ac.uk
No names, no pack [email protected]
. . . just like wind turbines but under water.
Pmax1
2 A U
316
27
Frederick Lanchester 1868-1946 Albert Betz 1885-1968
Unswept flow passage ≡ leaky pipes
≡ Vortex wake pollution
≡ Ignorance of flow angles
O’Doherty DM. Mason-Jones A, Morris C, O’DohertyT, Bryne C, Pricket PW, Grosvenor RI.
Interaction of marine turbines in close proximity.
EWTEC 2011
2.75
3.35
3
0.55
O’Doherty DM. Mason-Jones, Morris, O’DohertyT, Bryne, Pricket, Grosvenor. Interaction of Marine Turbines in Close Proximity. EWTEC 2011
R.A. McAdam, G.T. Houlsby, M.L.G Oldfield. Structural and Hydrodynamic Model Testing of the Transverse Horizontal Axis Water Turbine. EWTEC 2011
R.A. McAdam , G.T. Houlsby , M.L.G. OldfieldStructural and Hydrodynamic Model Testing of the Transverse
Horizontal Axis Water Turbine EWTEC 2011
Pow1
2 A U
316
27 Pow g A H U
.296 U3 g H U
Open flow field Duct
Bending moment atblade root
http://www.google.co.uk/search?q=Tidal+stream+turbine+Alstom&hl=en&client=safari&rls=en&tbm=isch&tbo=u&source=u
niv&sa=X&ei=BOBOUbPSJY6o0wXh2ICIBw&ved=0CEIQsAQ&biw=1042&bih=1505
GOOGLE IMAGES
NASA
Edinburgh vertical-axis, variable-pitch with rim power take off.
EWTEC Patras 1998
Pitch variation gives control of rotor forces
Contra-rotation cancels cross force and torque reaction in wake
70 60 50 40 30 20 10 0 10 20 30 40 50 60 700
0.2
0.4
0.6
0.8
1
1.2Downstream force on a 140 diameter rotor as a fraction of ideal
1.2
0
fdsi 4
FDSi 4
DR
2
DR2
Xi
Work goes through restricted passage to congested generation space
Second Oxford Tidal stream Workshop 2013
Are Nearly all Tidal Stream Turbines Designs Wrong?
Stephen Salter
Institute for Energy Systems
University of Edinburgh
www.see.ed.ac.uk/~shs
Google images
Speed up x 30Range up x 6000
Payload up x 20,000Cost per ton-mile down ÷ 100
Google images
Something for the simpletons
Laminaria Hyperborea (kelp) are found along the
edges of the Pentland Firth at depths up to 30 m.
Length can reach 3.5 metres.
Cf = ?
Google images.
Pentland bed stills. P Hayes. Fisheries Research Aberdeen 2006-8
68 mm bob
Friction coefficients for Fshear = 0.5 ρ U2 Cf
6.165 TW x 0.04 = 247 GW
Edinburgh vertical-axis, variable-pitch with rim power take off.
EWTEC Patras 1998
