A cross-flow device with an oval blade path: predictions and

Report
Hydrodynamics of tidal stream energy
devices with two rows of blades
Peter Johnson
PhD student, UCL Mechanical engineering, and
Lecturer, Nazarbayev University School of Engineering
?
with Adam Wojcik and Kevin Drake, UCL Mechanical Engineering
Hydrodynamics of tidal stream energy
devices with two rows of blades
Peter Johnson
PhD student, UCL Mechanical engineering, and
Lecturer, Nazarbayev University School of Engineering
with Adam Wojcik and Kevin Drake, UCL Mechanical Engineering
Support
Column
Guy cable
cable
Sea Bed
Guy cable
cable
cable
water speed
relative
speed
Generator
cable
blade
speed
lift
drag
Guy cable
Guy cable
Ft
N Fn
Fn
sin 
Ft
Fn
θ
N Fn
sin 
0.5 m
blade chain
2m
shaft
Aluminium
plate
wheel
shaft
Slider
track
Predictions
Definitions
Clockwise:
Θ = 0.5
Ft
Fn
M
2R
R
y
Clockwise:
Θ=0
x

W
2D vortex model results
Power coefficient
2D point vortex model using empirical blade data
Blade speed
o – Moonraker,
+ – Darrieus
chain
Attachment link
wheel
Blade
(carbon fibre)
S/steel
shaft
Nylon pads
(rapid prototyped)
Aluminium plates
Video
PII_001.wmv
Blade instrumentation concepts
Distributed load
Blade
(hollow carbon fibre shell)
Bending
member
Tracks
Blade
(hollow carbon fibre shell)
Strain gauges
Blade
How to record the signal from the strain gauge?
Tracks
61 mm
Carbon
fibre
blade
9 mm
Microlog
filter circuit
(inside blade)
Microlog
bluetooth
transceiver
Microlog
main PCB
Terminals
Microlog
main PCB
Dual
strain
gauge
18 mm
Polished
surfaces for
strain gauges
Holes for
cables
Microlog PCBs
Nano batteries
Charging circuit
Epoxy
escape
holes
Bending member
Filled with Silicone
Dowel pins
Filled with epoxy
Flush dowel pins
QinetiQ Plc.,
Naval testing facilities,
Haslar, near Portsmouth, UK
Results: Fourier fitting
Recap: definitions
Clockwise:
Θ = 0.5
Ft
Fn
M
2R
R
y
Clockwise:
Θ=0
x

W
Normal force
Normal force
Normal force
Summary of results for force normal to blade’s motion, Fn
Data here is for results with 3 blades
Tangential force; 6 blades
Tangential force; 6 blades
6 blades
x – experiment
o – vortex model (infinite blades)
– vortex model (finite blades)
for 6 blades
Tangential force; 3 blades
3 blades
carriage
Track
practical
tangent
tangent
wheels
ideal
Track
Cable-tie
(slack)
Cable-tie connects trailing
edge of blade to chain, to
limit pitching during corners
Tie clip
(tight)
Centrifugal
force
Cable-tie
extended
Centrifugal
force
3 blades
Many thanks to …
Kevin Drake,
Adam Wojcik,
Neil Collins,
Richard Winn,
Dan Fone,
Peter Kelly,
Sinan Hasan,
Savvas Achilleos,
Ian Eames,
Christian Klettner,
Andre Nicolle,
Christian Jonsson,
Tim McDonald,
Tristan Smith,
Ben Tompsen,
Chris Pyke,
Mike Johnson,
Joachim Baumgaertner,
And support from QinetiQ Plc., Norwin Electrics, Ashley
Power Ltd., JRD Ltd. , NCGE, NESTA, EPSRC, UCL.
Thank you… and questions
www.londonmarinepower.co.uk
(from Kaz: www.londonmarinepower.co.uk.nyud.net )
Results: Fourier fitting

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