This document summarizes a student project to design and fabricate a brimmed diffuser for a wind turbine. The brimmed diffuser is intended to increase the efficiency and power output of the wind turbine. The design of the brimmed diffuser is presented, including dimensions calculated based on the turbine diameter. Testing showed that the brimmed diffuser increased wind velocity and the power output of the turbine. The project demonstrates the potential for brimmed diffusers to improve wind turbine performance and power generation.

1. DESIGN AND FABRICATION OF
BRIMMED DIFFUSER IN WIND
TURBINE BY
S. MARIMUTHU @ MATHAVAN
(953211114027)
P. PON RAJESH KUMAR
(953211114032)
R. SIVAGAMINATHAN
(953211114049)
M. VIGNESH
(953211114055)
GUIDED BY
Mr. N. SANKARESWARAN, M.E., (Ph.D)
ANNA UNIVERSITY – TUTICORIN CAMPUS
DEPARTMENT OF MECHANICAL ENGINEERING
III YEAR

2. ABSTRACT
 This project work involves in the fabrication of BRIMMED DIFFUSER IN
WIND TURBINE.
To obtain a higher power output of the shrouded wind turbine, a shrouded
wind turbine equipped with a flanged diffuser has been developed, and
demonstrated power augmentation for a given turbine diameter and wind
speed
The flanged-diffuser shroud plays a role of a device for collecting and
accelerating the approaching wind.

3. PROBLEM DEFINITION
Efficiency of conventional wind turbine is low.
Conventional wind turbine produce more noise.
Separate yawing system is required.
Power production for a specific area is low.
Cut in velocity of conventional wind turbine is high.
In order to overcome the drawbacks in conventional wind turbine a brimmed
diffuser is used.

4. INTRODUCTION
 Today, one of the most important problem facing by our nation is the
shortage in power. The production in power is less and the need is increasing
day by day.
 So rather than implementing new ideas, working out for modifications in
the already existing ideas makes the investment in energy sources lesser.
 In India, investments in energy sources are major on wind farms.
 A special attachment to wind turbines, Wind Lens i.e. (BRIMMED
DIFFUSER) increases the efficiency of wind turbines.

5. Indirect form of Solar energy
In Wind Turbines
Kinetic energy of wind Mechanical energy Electrical energy
(rotor blades) (rotating shaft) (generator)
The movement of wind turbine blades explained by Bernoulli’s theorem
SOME BASICS OF WIND ENERGY

6. WIND-LENS CONCEPT
The Power developed (P) in the wind turbine is given by the
relation
P = Cp ρA (V)3
Where,
Cp = Power Coefficient
ρ = Density of air
A = Wind receiving area
V = Upstream velocity of wind
P ∝ V3
If one can accelerate the local wind speed by capturing and
concentrating the wind with some mechanism, there appears hope for
utilizing the wind power in a more efficient way.

7. Brim
WORKING
•The inlet shroud, a diffuser and a brim results in a low pressure area
behind the turbine which draws in more air creating even more power.
•As a result of the low pressure behind the diffuser , the air from the
surrounding which is in high pressure moves towards the low pressure
region.
•This in turns produces an vortex which increases the velocity of the wind
thereby increasing the efficiency of the turbine.

8. EFFECT OFBRIMMED DIFFUSER ON WIND TURBINE

9. Components of Wind Turbine with Brimmed Diffuser
Components Material
Blade PVC Pipe
Diffuser Aluminium Sheet
Truss Tower Steel
Nacelle Aluminium
Generator Commutated DC Motor
Hub Aluminium Plate

10. METHODOLOGY
Start ---------
Problem identification To increase the efficiency of the Wind
turbine.
Design of Shrouded wind turbine with
brimmed diffuser
Design proposed with brimmed diffuser.
Detailed design drawings Detailed drawings are drawn.
Purchase of materials Purchase of DC Motor and raw
materials.
Manufacturing process Manufacturing of truss tower, PVC
blades, DC motor shaft, DC motor coil,
Housing, Brimmed Diffuser and hub.
Assembly of Brimmed diffuser in wind
turbine as per proposed design
Assembly of truss tower, PVC blades,
Housing, Brimmed Diffuser, DC Motor
and hub.
Working model Wind turbine with brimmed diffuser
working
End -----------

11. DESIGN OF A BRIMMED DIFFUSER
Design Procedure for Brimmed Diffuser
Diameter of the rotor, D = 1010mm
Diameter of the hub, Dh
Dh / D = 0.2
Dh= 0.2x1010
Dh= 202mm
Length of the diffuser, L
L / D = 0.225
L = 0.225 x 1010
L = 228mm
Height of the Brim, H
H / D = 0.1
H = 0.1 x 1010
H = 101mm

12. Tip Clearance, Ht
Ht/ D = 1.5%
Ht= 0.015 x 1010
Ht= 15mm
Inclination angle of Diffuser, ɸ
tan ɸ = (Do - Di) / 2L
where, Do– Outer diameter of diffuser
Di - Inner diameter of diffuser
tan ɸ = (1140 – 1040) / (2x228)
tan ɸ = 0.219
ɸ = 12.370

13. Without Diffuser,
The velocity of wind V = 5m/s
Power, P = Cp x ρ x A x (V)3
= 0.5x1.522x(п/4) x(1.01)2x(5)3
P = 87.9 W
Velocity, V = п x D x N / 60
Speed, N = 5x60 / пx1.01
N = 94.55 rpm
Torque, T = P x 60 / 2 x п x N

14. = 87.9x60 / 2xпx94.55
Torque, T = 11040.01 N-mm
Torque, T = п x Ʈ x d3 / 16
Ʈ = 11040.01 x 16 / пx(12)3
Ʈ = 26.53 N/mm2
Shear stress Ʈ = 26.53 N/mm2

15. With Diffuser,
The velocity of wind V = 6m/s
Power, P = Cp x ρ x A x (V)3
= 0.5x1.522xп/4(1.01)2x(6)3
P = 131 W
Velocity, V = п x D x N / 60
Speed, N = 6x60 / пx1.01
N = 113.45 rpm
Torque, T = P x 60 / 2 x п x N
= 131x60 / 2xпx113.45

16. Torque, T = 11026.5 N-mm
Torque, T = п x Ʈ x d3 / 16
Ʈ = 11026.5x16 / пx(12)3
Ʈ = 32.498 N/mm2
From Design data Book, Pg. No: 1.12
Yield stress for C-45 Steel = 380 N/mm2
Allowable stress = 380/2 =190 N/mm2
Design stress < Allowable stress
Design is safe

17. RESULT
Without Diffuser
Power = 87.9 W
With Diffuser
Power = 131 W

18. ADVANTAGES
• Brim-based yaw control
• Significant reduction in wind turbine noise
• Improved safety
• Improved cut-in velocity
• Increase in output power as compared to conventional wind turbines

19. PHOTOGRAPHY

21. CONCLUSION
This prototype is simple, and the main advantages are increasing the
functionality of wind velocity and increasing over all power
generation without increasing the area of the rotor. Implementation of
this project increases the efficiency of wind turbine. It is used to
increase the power generation with brimmed diffuser. The application
areas are in wind turbine, ocean water turbines etc.
This “BRIMMED DIFFUSER IN WIND TURBINE” leads
to future device, which are helpful for mankind such as high efficiency
wind turbines.

22. REFERENCES
1. Kazuhiko Toshimitsu, Hironori Kikugawa, Kohei Sato, Takuya Sato.
Experimental Investigation of Performance of the Wind Turbine with
the Flanged-Diffuser Shroud in Sinusoidally Oscillating and
Fluctuating Velocity Flows. . J. Wind Eng. Ind. Aerodyn.
2. Kothari, D.P., Umashankar, S.,2014. Wind Energy Systems And
Applications. Narosa Publications.
3. Ohya, Y.; Karasudani, T.; Sakurai, A.; Abe, K.; Inoue, M. Development
of a shrouded wind turbine with a flanged diffuser. J. Wind Eng. Ind.
Aerodyn. 2008
4.
5. Ohya, Y.; Karasudani, T. A Shrouded Wind Turbine Generating High
Output Power with Wind-lens Technology. J. Wind Eng. Ind. Aerodyn.
6. Faculty of Mechanical Engineering, PSG College of Engineering.
(2011) ‘Design Data’, Kalaikathir Achchagam.