1. Anatomy of Wind Turbines
P M V Subbarao
Professor
Mechanical Engineering Department
I I T Delhi
Argons of a Machine to Generate Maximum Action …..

2. Learnings from Betz Theory
A Rotor (energy converter) which can generate an axial induction factor greater than zero is capable of extracting the mechanical power from a free-stream wind.
The extractable mechanical power increases with the third power of the wind velocity.
The power increases linearly with the cross-sectional area of the (rotor) converter.
Even with an ideal airflow and lossless conversion, the ratio of extractable mechanical work to the power contained in the wind is limited to a value of
When the ideal power coefficient achieves its maximum value cP = 0.593, the wind velocity in the plane of flow of the converter amounts to two thirds of the undisturbed wind velocity and is reduced to one third far behind the (rotor) converter.

3. The Power Extraction Analysis for Wind Turbines

4. Classification of Wind Machines
The adjectives horizontal or vertical attached to the two major classes of wind machine.
This classification refers to the geometrical aspect of the driving shaft on which the rotor/wheel is mounted.
An oldtime wooden machine with four sails (a type typified by the term Dutch windmill) is now called a horizontal-axis wind turbine (HAWT).
Past usage terms it as a vertical windmill, because the path of a point on a moving blade lies in a vertical plane.
A machine with a central vertical axis and a number of straight or bent vanes arranged in a direction more or less parallel to the shaft is today called a vertical-axis wind turbine (VAWT).
In past times this was called as a horizontal windmill.

5. Blade type, Number of Blades and Speed of Rotor
Runs at high Speed
Used for driving Generators
Runs at Low Speed
Used for driving Reciprocating Pumps

6. Speed of A Wind Turbine
A rotor rotating at low speed will allow the wind to pass unperturbed through the gaps between the blades.
A rotor rotating rapidly will appear as a solid wall to the wind.
It is a challenge to design the blades of the rotor to make the rotor to run at an optimal blade speed to angular speed to extract highest power.
This ratio is determined by the tangential velocity of the rotor blades in relation to the undisturbed axial airflow, the wind velocity.
This is called as the Tip Speed Ratio λ, commonly referenced to the tangential velocity of the rotor blade tip.

7. My Exposure to Development of A Realtime Turbo-machine
IIT Experience Vs Rural Invention…..

9. Samantara akSha-rekhA Jhal Chakra

10. Analysis of the Mangal Singh’s Design
Diameter of the wheel : 4m.
Speed of the wheel: 13 RPM.
24 blades !
Huge Diameter !
Very Low Speed!
Weighing more than a ton!
Huge material cost!
The speed of A common pump or Generator is 1500 RPM.
A gear box is required to Increase the speed 120 times!
Very costly gear box.

11. Scientific Model of The TurbineRp w Re 2j 1D
hj, Vj 1A 1C 1B

12. Minimum Number of Buckets
tj : Time taken bye the jet to travel lj
tb: Time taken by first bucket to travel y q y Rp Re d
hj, Vj lj w
For better working tj < tb

13. Analysis of the Problem
Water is falling form a height H, called Head.
The velocity of the stream when reaches down most point is:
Newton’s Second Law applied for present problem:
Any Obstacle, which changes the direction of the stream (of given mass flow rate) will experience a force.
If the agent is fixed to a shaft, it can generate a torque.
The product of torque and speed of the agent is Power.

14. The Concept

15. Blade Geometry Blade Cross Section Kinematics of Blade & Jet
Outlet Jet
Inlet jet

17. Proposed Civil Construction Layout

18. Design of Barrier and Spillway

19. Scientific Model of The TurbineRp w Re 2j 1D
hj, Vj 1A 1C 1B

20. The New Design Blades and Assembly

21. The New Design of Wheel

22. IIT Delhi Design & Mangal’s Make

23. IIT Delhi Model

24. Design II : Krishi Vigyan Kendra ,Jagdishpur, Sonipat
5KW design with 3.7KW Irrigation Pump

25. Comparative study on development of Micro hydro water wheel
$400
$320
$2700
Cost of gear box
$170
$160
$1800
Cost of wheel
impulse
Principle 15 14 24
No. of blades
86%[t] 76%[p]
72%[t] 68%[p]
40%[t] 20%[p]
Efficiency
22l/s
22 l/s
Pump discharge
450l/s
400l/s
1800l/s
Water Consumption
run
5kw
6kw
Power developed 1
1.5
Head at site in m
1.26 4
Diameter in m
New Design II
(KVK, Sonipat)
Haryana
New Design I
(Semera Village)
Lalitpur,UP
Farmer ’
s version
Bhailoni Village
Specification

26. Uttaranchal A Land for Traditional Harvest of Hydro Power

27. Vertical Axis Over Shot Water Wheels
Source of power in Rural Uttaranchal

28. Layouts for Uttaranchal Units : HESCO
Penstock
Water Wheel
Main Shaft
Bush Bearing
Wooden Base
Grinder adjusting lever
Grinding Wheel
10” Pulley
12” Pulley
Gear Box
Generator
Canal
Forbay
New Design

29. Specification of upgraded wheel for Garwhal area

30. Intersection of Wind & Blade

31. The Art of Time Scale Analysis
There exist at least two important time scales in any fluid flow problem.
Time taken for any given blade to move into the position occupied by its predecessor, tb.
Time take for the disturbed wind to re-establish itself to natural state, tw.

32. The Skill of Group Co-ordination

33. Capacity Vs Number of Blades
For a given efficiency , a wind turbine with large capacity will run at lower speed.
What is the lowest RPM (Revolution Per Minute) a single bladed turbine can make without loosing its efficiency drastically?
It is 60 RPM or one revolution per second. Why?
Because it should sweep whole rotor area in one second.
If turbine rotates slower than this, it will miss some air particles and it's output power will be low.
However if it rotates faster than one revolution per second it will produce more power which is better.
But faster rotating blades create more stresses on overall structure.
Therefore one bladed turbine should run at highest possible safe rpm.

34. Low Speed for Higher Number of Blades
A two bladed turbine can run at lower speed with high efficiency.
This is because while one blade sweeping one half of the circle area, the other blade is sweeping the other half.
By using same analogy a three bladed turbine can run much lower speeds with high efficiency.
Low speed turbine increase the cost of electrical equipment.
Higher number of large blades will increase wind turbine and civil structure costs.
A techno-economically viable option is essential.

35. An Ultimate Art of Wind Turbine Design

36. Common Industrial Practice

37. Performing Under Highly Uncertain Conditions

38. Instantaneous Direction of Wind
Rotor Plane
(t) V0