po.id development of shrouded wind turbines ......microsoft powerpoint -...
TRANSCRIPT
Next generation wind lens have been developed. This
version has shorter diffuser to reduce structural weight
and narrower brim to reduce wind loads. This can be
an advantage for the application to larger wind turbines.
Performances of wind lenses with different length:
Field test result of 5kW Cii-type Wind-Lens turbine:
Further optimization of the wind-lens shape (Ci):
Also an optimization study of the shape of wind lens
has been done. The newest type has cycloid cross
section.
1) Two-five time increase in output power
compared to conventional wind turbines
2) Brim-based yaw control
3) Significant reduction in wind turbine
noise due to suppression of tip vortices
4) Improved safety
5) Possible reduction in Doppler radar
interference
Numerical simulation by DNS for original and new
wind lens (Ci):Abstract Field Experiment for a 500W Wind-lens
Ongoing and future wind farm projects
Objectives
Remarkable merits of the Wind Lens
EWEA 2011, Brussels, Belgium: Europe’s Premier Wind Energy EventEWEA 2011, Brussels, Belgium: Europe’s Premier Wind Energy Event
This study presents an innovation related to wind
power enhancement technology named “Wind Lens”.
Wind power generation is proportional to the third
power of the wind speed. If we can increase the wind
speed, specifically by capturing and concentrating the
wind energy locally, the output power of a wind turbine
can be increased substantially. To embody the
scenario, we have devised a simple shroud structure
which intentionally creates vortices behind it to draw
more mass flow into the wind turbine. The structure has
been named “Wind Lens”.
The wind lens has a compact diffuser shroud with a
broad-ring rim at the exit periphery. Our wind turbine
system consists of the wind lens and a turbine inside.
This system has demonstrated power augmentation for
a given turbine diameter and wind speed by a factor of
about 2-3 compared with a bare wind turbine.
Next generation diffusers have been developed and
the details are given in this study also. The significant
features of the wind-lens technology include, improved
safety, reduction of acoustic noise and Doppler radar
interference. We believe the wind lens can be quite
suitable for installation in a variety of sites, even in well-
populated areas. This study also discusses the latest
development on 100kW scale wind-lens turbine system.
Development of highly efficient
small-type wind turbine
Concentration of wind energy
Wind turbine +
WIND LENS
collection and acceleration
device for wind
Brimmed Diffuser - Wind Lens
A “Brim” is attached to a diffuser shroud to improve
wind collection and acceleration. The idea is to induce
formation of strong vortices.
A wind turbine with the wind lens
The mechanism:The strong vortices created by the diffuser and the brim
produce low pressure region behind the turbine. This increased
pressure difference helps the wind to flow more into the wind
lens.
WIND LENS
A collection-acceleration
device
(Inlet shroud + Diffuser +
Brim)
Result of 500W wind-lens turbine field test:
The result shows a significant increase of power output
as much as 400% compared to conventional turbine.
However, for larger turbines, reduction of the mass of
the wind lens, and the size of the brim is important.
Short brimmed wind lens
Cw
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
2 3 4 5 6 7
通常型(つば高さ5%)
延長型(つば高さ
5%)通常型(つば高さ
10%)延長型(つば高さ
10%)
Old WL 5%
New WL 5%
Old WL 10%
New WL 10%
λλλλComparison between original WL and new WL
Original wind lens has curved
diffuser and straight brim. Two
parts are assembled together.
The new version of the WL has
continuous structure and has
Cycloid shape cross section.
Original (old) diffuser shroud with brimOriginal (old) diffuser shroud with brimOriginal (old) diffuser shroud with brimOriginal (old) diffuser shroud with brim of 10% heightof 10% heightof 10% heightof 10% height
Unified (new) diffuser shroud with cycloid sectionUnified (new) diffuser shroud with cycloid sectionUnified (new) diffuser shroud with cycloid sectionUnified (new) diffuser shroud with cycloid section
streamlinesstreamlinesstreamlinesstreamlinespressurepressurepressurepressurevorticity
Wind Energy Utilization Project in Fukuoka city:
Hundred kW Wind Lens turbine at Kyushu-U:
Ocean Energy Farm project:
Development of combined energy farm on the ocean
surface is currently ongoing at Kyushu University. The
project begins with building an experimental wind farm
on a floating structure on the ocean surface.
5kW Wind-lens turbines on the seashore of Fukuoka, Japan
Wind-lens
turbines
Wind-lens
turbine
Numerical Simulation of Airflow around Numerical Simulation of Airflow around
Urban Area by the RIAMUrban Area by the RIAM--COMPACTCOMPACT®® CFDCFD
Hakata bayHakata bayFlowFlow
Hakata bayHakata bay
streamlinesstreamlinesstreamlinesstreamlinespressurepressurepressurepressurevorticity
Brim
0
50
100
150
200
250
300
350
0 2 4 6 8 10
Wind Speed [m/s]
Ou
tpu
t P
ow
er [
W]
Power Curve of Cw=1.4
Field Data (10min. ave.)
W.T. only
four times increase
conventional wind turbine
Power coefficient
Cw=P/0.5ρU∞3A
P: Power output
A: Rotor swept area
0.0
0.2
0.4
0.6
0.8
1.0
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0rω/U0
Cw
C0
Cⅰ
Cⅱ
Cⅲ
W.T. only
λ: Tip speed ratioC0C0C0C0
CCCCⅰⅰⅰⅰ
CCCCⅱⅱⅱⅱ
CCCCⅲⅲⅲⅲ
Performance Curves for C-type diffusers with different length (h=0.1D, Uo=8m/s)
0
500
1,000
1,500
2,000
2,500
3,000
3,500
0.0 2.0 4.0 6.0 8.0 10.0 12.0
m/s
WField Data (1min. average)
Cw=1.0 (Wind-lens Turbine)
Cw=0.4 (Conventional Wind Turbine)
Conventional
Wind Turbine
Wind-lens
turbine
2.5 timesincrease
Cw*=0.54based on the lens diameter
DEVELOPMENT OF SHROUDED WIND TURBINES
WITH WIND-LENS TECHNOLOGYYuji Ohya1, Takashi Karasudani1, Tomoyuki Nagai1, Chris Takashi Matsuura2,3, Hugh Griffiths2
1) Research Institute for Applied Mechanics, Kyushu University, Fukuoka, Japan
2) University College London, London, UK, 3) ENGRID ltd, London, UK
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