CHAPTER 1

INTRODUCTION

1.1 INTRODUCTION

Wind turbine has become popular in Malaysia but the product must be designed to

suit atmospheric condition in Malaysia. It also can give benefit for all users to reduce

the cost and also can generate the energy. Wind turbines are systems that attach the

kinetic energy of the wind for useful power. Overall, the weight and cost of the

blades are the keys in manufacture wind energy competitive with other sources of

power. Thus, based on cost alone, reducing the weight of the blade is an important

issue worthy of research. Another factor that plays a very important role is the

operational life of the machine, but the main factor is the blades. As the requirements

for improved stiffness, fatigue life, reliability and efficiency increase, so do the

challenges of developing innovative design solutions.

However, if change the design and material the blade can be generated at the certain

high level and Malaysia has the potential to generated wind turbine blade. In fact, by

using composite material and redesign the blades can improve the energy, save cost

and long term for user.

For home user usually used blade made from composite especially in Malaysia

because this material is light weight. It also, can change it to existing wind turbine

blade.

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1.2 BACKGROUND OF STUDY

Wind turbine is a device to convert the kinetic energy in the wind into mechanical

power. It also called wind energy, into mechanical energy. This wind flow, or motion

energy can be used to generate electricity from wind turbine and also can reduce the

cost. This wind turbine focuses to generated energy for home owner. For example, a

wind turbine can be used to drive machinery, for grinding grain or pumping water. In

many applications, a wind turbine is coupled to an electrical generator. Smaller wind

turbines are used for applications such as battery charging or auxiliary power on

sailing boats.

Wind turbine has two basic groups for example the horizontal axis variety, and the

vertical axis design. A horizontal Axis Wind Turbine is the most common wind

turbine design. In addition to being parallel to the ground, the axis of blade rotation is

parallel to the wind flow. Although vertical axis wind turbines have existed for

centuries, they are not as common as their horizontal counterparts. The main reason

for this is that they do not take advantage of the higher wind speeds at higher

elevations above the ground as well as horizontal axis turbines.

Due to irregular wind and lower wind speed velocity, Malaysia is unsuitable for large

scale wind turbine. However, if design new blades and change the material can be

generated at the certain high level. The larger, 2.0 metre diameter rotor will sweep

across more wind, and therefore it can produce more power, in a given windspeed.

The smaller, three bladed rotors will have a slower tip speed, but will run more

smoothly because it has three blades.

Wind turbine blades are the main criteria for high speed to generate energy. Even

though, wind turbine is the new technology in Malaysia, there are ways to improve

the energy capture.

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1.3 PROBLEM STATEMENT

Global warming is the recent problem to the whole world. Governments and various

organizations of all developed and developing countries are trying to reduce it. In

this era human life is highly dependent upon electrical energy, even we can’t think

about life without electricity. But today most of electrical demand is met by

conventional energy sources. Now the electricity prices and global temperature is

increasing. Wind turbine is one of the solutions one of them, but is not suitable for

Malaysia meteorological conditions, for example insufficient wind speed. The

existing product of low speed wind turbine has some problems on the important part

such as the blades. Existing blades also less aerodynamic and heavy weight. Another

problem is excessive noise and high vibration. The hub also is distorted and low

speed to generate the energy. For this case the best solution to improve the design

and find the best material for blades. The most important thing is the blade can rotate

or spin even if in low wind speed.

1.4 PROJECT OBJECTIVES

The main objectives of the project are as listed below:

To design and fabricate an aerodynamic composite wind turbine blades to

improve the rotation of turbine and catalyst more electric charge.

To improve hub function on blade to increase blade rotation

1.5 PROJECT SCOPES

This project is limited to the following issues:

1. To study and compare various shape of blades.

2. To find the best dimension of blade and hub.

3. Come out with result stress analysis and blade deformation analysis.

4. Come out with result Computational Fluid Dynamics analysis using Ansys.

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1.6 PRELIMINARY MARKET RESEARCH

Market research was done by searched through internet, report and books about wind

turbine blades. All of the information about the wind turbine blades that our group

gathers finds that the wind turbine blades is better use the fiber glass material to

fabricate the blades.

In order to get a more precise information about the wind turbine blades, our group

must study hard about the criteria of blade and the other part for example the hub,

casing for generator and tail wind turbine.

1. .Efficient wind turbine blade design made from composite materials.

Figure 1.1 The winners of the state wide competition (Wire, 2009).

Gov. John Baldacci from Sumner Memorial High School won the competition to

build an efficient wind turbine blade from composite materials at the University of

Maine. The blade is especially designed for maximum wattage keeping in mind the

overall lightness and aerodynamics. This student teams sent a composite materials to

design a prototype blade. This blade should be no longer than 18 inches and the

turbines could be no greater than 42 inches in diameter. The teams also wrapped their

blades with a fibreglass cloth and infused them with a resin that hardened the blades.

The overall aim was to design a blade that would generate the most wattage.

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2.

Figure 1.2 Advantages of composite material (Shed, 2010).

Fibre glass has advantage for example higher strength to weight ratio as compared to

other materials. Besides that this material is light weight components are easier to

install, requiring less equipment, time, and manpower costs.

3.

Figure 1.3 High efficiency 3 blade turbines (Woofenden & Piggott, 2012)

The ratio between the speed of the blade tips and the speed of the wind is called tip

speed ratio. High efficiency 3-blade-turbines have tip speed/wind speed ratios of 6 to

7. Modern wind turbines are designed to spin at varying speeds (a consequence of

their generator design, see above). Use of aluminium and composite materials in

their blades has contributed to low rotational inertia, which means that newer wind

turbines can accelerate quickly if the winds pick up, keeping the tip speed ratio more

nearly constant. Operating closer to their optimal tip speed ratio during energetic

gusts of wind allows wind turbines to improve energy capture from sudden gusts that

are typical in urban settings.

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1.7 CURRENT SCENARIO

1. Wind turbines as RE source

Figure 1.4 Excellent situation at Sabah (Lee, 2012).

This article focus at Sabah’s a good potential in harnessing energy from wind by

putting up wind turbines offshore on its northern tip. Sabah also could be the

beneficiary of its RE initiative in testing the viability of vertical wind turbine power

generator.

Sabah has the right geographic factors and excellent situation to generate enough

wind for wind turbine projects. One of the RE industry solutions offered by Pernec is

wind turbine. Pernec claims that its wind turbine emits low noise and can generate

between 300W and 25kW; most suited for windy and coastal areas or islands.

2.

Figure 1.5 Pulau Perhentian Kecil now powered by wind (Radhika, 2007).

Pulau Perhentian Kecil in Terengganu have energy generating system to provides

electricity. This energy system which features a wind turbine and hybrid solar

generator and battery its debut at the tourist paradise island Perhentian Kecil

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recently. With this first-of-its-kind energy system in Asia, tourists can look forward

to more environment-friendly excursions compared to previously when diesel-

powered generators supplied power to this tiny island off the coast of Terengganu.

Besides that, Mentri Besar Datuk Seri Idris Jusoh launched the system at a traditional

fishing village on the island.

3.

Figure 1.6 Commercial wind energy generation may be possible after all

(Shaharuddin, 2012).

Dr Chong Wen Tong from Universiti Malaya say, who has always been interested in

finding a reliable wind source for energy generation, may have found the answer.

Around three years ago, he developed a wind energy recovery system from air

exhaust outlet those great fans usually located on top of commercial buildings for air

conditioning.

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4.

Figure 1.7 UPM First Wind Turbine Hybrid with Solar Panel (kiki,

2010).

Recently, Our Malaysia local university-University Putra Malaysia (UPM) had kick

start the Renewable Energy (RE) Initiative by installing few units of stylish wind

turbines and solar panels in UPM-Serdang main campus.

5. Performance of Wind Turbine Based on Wind Speed in Kangar, Northern

Malaysia

Figure 1.8 Performance Wind turbine at Kangar (Daut, Irwanto, & Irwan,

2011).

Nowadays, wind energy is crucial for electricity companies as it is renewable and

free resource. Malaysia has a good prospective in wind energy and have decided to

opt for the wind energy to replace the fossil fuel which is non-renewable energy.

Malaysia faces the four seasons such as southeast monsoon, northeast monsoon and

two shorter periods of inter monsoon seasons. Hence, wind over in Malaysia is

generally light with the speed less than 8 m/s.

6. Blade Material

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Figure 1.9 Fibre glass commonly used for Wind Turbine Blade (Austin,

2011).

Composite materials, such as fiberglass, are currently the most commonly used

materials in wind turbine construction. Fiberglass is generally only used for small,

domestic applications, because fiberglass inclines to be more fragile than other fibre

based materials. That makes fiberglass a liability for commercial purposes.

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CHAPTER 2

LITERATURE REVIEW

2.1 WIND ENERGY

Wind energy was start development since the early 1980’s. Wind energy system has

own advantages between the other renewable energy. The rotor must have design of

aerodynamic device, for example the wing or rotor blade with an aerodynamic shape,

to be able to rotate smoothly. Today nearly all wind turbines have three blades

because the stability better than using two blades. Besides that, the high noise can

reduce if usage three blades (Brondsted, Lilholt, & Lystrup, 2005).

2.2 WIND TURBINE BLADES

2.2.1 Design of Wind Turbine Blades

Design of blades is the most important part to conduct the wind turbine system.

Thus, blades also must have special design to capture the maximum wind. Blade

design for the small horizontal axis wind turbine is not difficult because there have

various designs announce on the internet. But then, for the vertical axis wind turbine

is really a difficult to design because there have no common model blades design yet.

Blade design also starts with air foil shapes. Air foil sections also take serious for this

schem (Blanton & Preston, 2012). It is anticipated that the aero-elastic blade will

passively adapt its shape to the wind direction and speed leading to improve

aerodynamic blade characteristic, reduce loads, and improved performance Airfoil

with increased lift coefficient (Sunara, 2012). Design of blades can improve the

length to capture more wind at low speed, and then can retract to operate safely and

efficiently at high wind speeds (Richardson, 2009).

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Table 2.1 The two mechanisms of propulsion compared (Schubel & Crossley, 2012).

Propulsion Drag Lift

Diagram

Relative WindVelocity

= Wind velocity - Blade velocity ¿√ 2

3Wind Velocity2+BladeVelocity (dr )

Table 2.2 Main features of the two rotor designs (ITDG, Fernando, & Piggott, 2001).

Country of

origin DesignerPeru Teodoro Sanchez Sri Lanka Sunith Fernando

Blade section NACA 4412 K2

Diameter 1.7metres 2.0metres

Tip speed ratio 5 6

Number of

blades3 2

Design

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Table 2.3 Various types of blades design for horizontal and vertical axis wind

turbine blades (Meyers, 2012).

NoHorizontal Axis Wind

Turbine

Vertical Axis Wind Turbine

i.

ii.

iii.

iv.

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v.

vi.

vii.

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Table 2.4 Comparison Lift-based and drag based Wind Turbines (Bagiorgas,

Assimakopoulos, & Theharopoulos, 2006).

Lift-based Wind Turbines Drag-based wind turbine

More energy can be extracted from

wind using lift rather than drag, but

this requires specially shaped airfoil

surfaces. The airfoil shape is designed

to create a differential pressure

between the upper and lower surfaces,

leading to a net force in the direction

perpendicular to the wind direction.

In drag-based wind turbines, the force of

the wind pushes against a surface, like an

open sail. The Savonius rotor is a simple

drag-based windmill that you can make at

home. It works because the drag of the

open, or concave, face of the cylinder is

greater than the drag on the closed or

convex section.

2.2.2 Material for the wind turbine blades

Wind turbine blades have many types to manufacture. Besides that, wind turbine

blades can be improve from better designs, material, manufacturing, analysis, and

testing. The material of blades must be low weight and rotating inertia to increase the

energy capture.

The blades must also high rigidity because this is important case for stability wind

turbine blades. Therefore, resistance to fatigue and wear also must take serious. Each

material has differemce advantages and disadvantages in the manufacture of blades

design. Today nearly, all large horizontal-axis wind turbine blades are usually made

from composite materials to reduce the weight while attaining a reasonable strength

to weight ratio (Chena, Gaub, & Chena, 2011). Composite material has many

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advantages for example very stiff and strong, and yet lightweight fibres of glass

(Walczyk, 2010).

a) Materials Requirements

These operational parameters and conditions lead to the following requirements

focused on stiffness, density, and long-time fatigue:

High material stiffness is needed to maintain optimal aerodynamic

performance.

Low density is needed to reduce gravity forces.

Long fatigue life is needed to reduce material degradation.

2.2.3 Difference material used for Wind Turbine Blades

The description of difference material as below:

i. Fibre glass Blades is the popular wind turbine blades material for

both large and small wind turbines. Fibre glass materials are ideal for

producing wind turbine blades because of their strength, light weight

and ability to be tailored to provide the precise mechanical properties

needed for any blade design. Fiberglass also has many positive

comments between other material from the article and in website

forum (Richardson, 2009).

Figure 2.1 Fiber glass blades (Richardson, 2009).

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Table 2.5 Advantages and disadvantage of Fiber glass wind turbine blades (Brondsted et al., 2005).

Advantages Disadvantages

Resin/catalyst levels and the resin

content in the fiber are accurately

set by the materials manufacturer.

High fiber volumes can be safely

achieved.

Materials cost is higher.

The materials have excellent health

and safety characteristics and are

clean to work with.

Autoclaves are usually required to

cure the component. These are

expensive, slow to operate and

limited in size.

Fiber cost is minimized in

unidirectional tapes since there is no

secondary process to convert fiber

into fabric prior to use.

Tooling needs to be able to

withstand the process temperatures

and pressures involved.

Resin chemistry can be optimized for

mechanical and thermal

performance, with the high viscosity

resins being impregnable due to the

manufacturing process.

Core materials need to be able to

withstand the process temperatures

and pressure.

The extended working times means

that structurally optimized, complex

lay‐ups can be readily achieved.

Difficult to make.

Potential for automation and labor saving.

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ii. Woods blades usually used in simple wind turbine and small wind

turbine. It’s easy to design, easy to fabricate and also easy to

destroyed. It also not long term used. And then about the cost for

manufacture is cheapest.

Wood is another common material for small and homemade. While it

is a readily available, inexpensive material, wood poses several

problems for the home. If it is not correctly treated, wood is extremely

at risk to weather, warping with moisture or becoming brittle in the

sun. In addition, wood is not very tough under lateral stress, so heavy

winds can snap a wooden blade with little difficulty.

Figure 2.2 Wood blades (Richardson, 2009).

iii. Polyvinyl Chloride blades (PVC) only applied in small wind turbine.

It’s have lightweight characteristic and easy to install. About the cost

also same with the woods blades.

PVC blades are an inexpensive blade option commonly used by does

it yourself turbine manufacturers. One advantage of the material is the

ease with which the manufacturer can shape it individually. It is also

comparatively inexpensive, which makes it attractive to budget

constrained operations. However, when exposed to the elements, PVC

constantly weakens until it becomes very brittle and forms tiny

hairline cracks on the surface. The result is that an errant breeze could

crack the blade and shut down the turbine.

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Figure 2.3 PVC blades (Richardson, 2009).

iv. Aluminium alloy blades in some countries, this type of blades are

used for 1kW-5kW wind turbine.

Many manufacturers offer precision built aluminium blades. While

most large scale generators do not use these blades, they are an

excellent material for small turbines. While they are relatively heavy

compared to plastics, aluminium blades are weather resistant, resilient

and available from many suppliers. The down side is that they are

more expensive than other options. Furthermore, the maximum rotor

diameter is strictly limited by the material's weight.

Figure 2.4 Aluminium alloy blades (Richardson, 2009).

2.2.4 Fiber Glass Material

Fiberglass is a lightweight, extremely strong, and robust material. Even if strength

properties are somewhat lower than carbon fiber and it is less stiff, the material is

typically far less brittle, and the raw materials are much less expensive. Its greater

part strength and weight properties are also very favorable when compared to metals,

and it can be easily formed using molding processes. Glass fibers for composites

have a good combination to manufacture the small wind turbine blades (Brondsted et

al., 2005).

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Figure 2.5 Different physical forms, fine ground, chopped or woven (Harris, 1999).

Table 2.5 Advantages and disadvantages for fiber glass material (Harris, 1999).

No. Advantages Disadvantages

1 Lower density (20 to 40%) Not often environmentally

friendly.

2 Higher directional mechanical properties Low recyclability

3 Higher Fatigue endurance Cost can fluctuate

4 Higher toughness than ceramics and glasses. Can be damaged.

5 Versatility and tailoring by design Anisotropic properties.

6 Easy to machine Matrix degrades.

7 Can combine other properties (damping,

corrosion).

Low reusability.

8 Cost.

2.2.5 Composite Material

Composites can be divided into laminates and sandwiches;

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a. Laminates – layers of composite materials bonded together (Walczyk, 2010).

b. Sandwiches – multiple layer composite structure consisting of a low‐density

core between thin faces (skins) of composite materials (Walczyk, 2010).

Figure 2.6 Diagram showing the stiffness composite is better than between

other material (Brondsted et al., 2005).

2.3 AERODYNAMIC

Aerodynamic performance is major for efficient rotor design. If don’t have

aerodynamic the blades high possibility can’t operate. Aerodynamics is a very

important aspect of wind turbines. There are still some fundamental concepts that

apply to all turbines. The aerodynamics of a horizontal axis wind turbine (HAWT) is

not straight forward. The air flow at the blades is not the same as the airflow further

away from the turbine. A resistant drag force which clash with the motion of the

blade is also generated by friction which must be reduced (Ph. Devinant, 2002).

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2.3.1 Number of Blades

For large marketable machines, the upwind, three bladed rotor is the industry

accepted the configurations. The three bladed also have advantages over by using the

two bladed configurations. For the blade number choice is then a balance among

blade stiffness for tower clearance, aerodynamic efficiency, and tower shadow

impulsive noise (Sunara, 2012). The three bladed rotor configurations appear to

provide the best balance.

Another consideration the three blades is a more dynamically balanced rotor. In

calculation, two-bladed rotors are more sensitive to one per rev, rotor mass also

imbalance vibration. For more rotor dynamics of a three bladed rotor tend to result in

lower operating and maintenance cost (Tangler, 2000).

The main reason why the two blade rotor can work at higher tip speed ratio is that it

only has two blades. The smaller, three bladed rotors will have a slower tip speed,

but will run more smoothly because it has three blades. If use larger than 2.0 metre

diameter rotor the blades will sweep across more wind, and can increase the power,

in a given wind speed (ITDG et al., 2001).

2.3.2 Structural for Blades

As the Wind Energy Market has matured the optimization of blade design has

become critical as blade lengths and weights have increased. As a consequence the

one core fits all approach is no longer relevant for a modern wind turbine blade.

Structural core is used in both the structural shell and shear webs of a standard

infusion blade design. The material requirements for a structural core can vary

considerably from shell to shear web and also from one area of a shell to another.

Therefore, to optimize the design, weight and performance of a blade the blade

designer may make use of a number of core products.

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Figure 2.7 Structural of blades(Walczyk, 2010).

a) Structural and Materials information (Valencia, 2004):

Materials used in the construction of the blade.

Engineering properties of the materials: Young’s modulus,

Poisson’s ratio, failure strains.

Materials lay-up and orientation of the layers.

Materials used in the construction of shear webs and dimensions and positions relative to the air foil geometries.

2.3.3 Structural Blade Regions

The modern blade can be divided into three main areas classified by aerodynamic

and structural function

Figure 2.8 The three blade regions (Schubel & Crossley, 2012).

i. The blade root

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This section is first aerofoil and have carries the highest loads to support the blade.

It’s also low relative wind velocity is due to the relatively small rotor radius. The low

wind velocity leads to reduced aerodynamic lift leading to large chord lengths.

Therefore the root region of the blade will typically consist of thick aerofoil profiles

with low aerodynamic efficiency.

ii. The mid span

Aerodynamically significant the lift to drag ratio will be maximised. Therefore

utilising the thinnest possible aerofoil section that structural considerations will

allow.

iii. The tip

Aerodynamically critical the lift to drag ratio will be maximised. Therefore using

slender aerofoils and specially designed tip geometries to reduce noise and losses.

Such tip geometries are as yet unproven in the field, in any case they are still used by

some manufacturers.

2.3.4 Blade Geometry

Blade Geometry Minimum cost of energy is the criterion now used to optimize blade

geometry rather than maximum annual energy production. To optimize on minimum

cost of energy requires a multi-disciplinary method that includes an aerodynamic

model, a structural model for the blades, along with cost models for the blades and

all the major wind turbine components. Minimum cost of energy also benefits from

higher rotor speeds, which are constrained by noise considerations (ITDG et al.,

2001).

Geometric information (Valencia, 2004):

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Aerofoil geometry at known stations from the root.

Length of the blade.

Twist angle of the blade at several aerofoil stations.

Chord length.

The distance from the nose of a station to the blade generator line. (X-offset).

Shear web dimensions and positions relative to the aerofoil geometries

previously defined.

2.3.5 Blade Element

In blades element have two key assumptions (Ingram, 2011):

There are no aerodynamic interactions between different blade elements

The forces on the blade elements are solely determined by the lift and drag

coefficients

Figure 2.9 Rotating Annular Stream tube notation (Ingram, 2011).

Figure 2.10 The Blade Element Model (Ingram, 2011).

The forces on the blade element are shown in Figure 4, note that by definition the lift

and drag forces are perpendicular and parallel to the incoming flow (Ingram, 2011).

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Figure 2.11 Forces on the turbine blade (Ingram, 2011).

2.3.6 Angle of attack

To become the best performance in wind turbine system angle of attack also can

apply. The blade is deformed due to wind, when a blade is rotate. This deformation

makes the angle of attack at the tip portion of the wind turbine blade larger than a

design value, thus increasing noise (Hayashi, Hosoya, & Karikomi, 2010).

After the angle of attack increases to approximately 18 to 20 degrees, the air can no

longer flow smoothly over the top wing surface, because the airflow cannot make

such a great change in direction so quickly, it becomes impossible for the air to

follow the contour of the wing.

Figure 2.12 Angle of attack on blade wind turbine (F.L Ponta, 2006).

25

Figure 2.13 Angle of attack (F.L Ponta, 2006).

2.3.7 Aerofoil Section

Aerofoil sections also take serious for this system to find the best design.

Conventional aircraft aerofoil design must have been used for wind turbine blades. If

blades condition is clean, the aerofoils result in too much power in high winds, and

the generator maybe can burned out. To avoid this problem, blades have been

inclined more toward stall to reduce peak power which results in reduced rotor power

to thrust ratios and high wind-farm array losses (Somers & Tangler, 1999).

Figure 2.14 Aerofoil sections the turbine blade (Somers & Tangler, 1999).

2.3.8 Aerodynamic noise

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Factor aerodynamic noise depends on design and site parameters for example:

The rotational speed.

The inflow characteristics.

The blade tip geometry.

The tower.

The blade geometry.

These entire factors affect the overall performance of the wind turbine. To become

the good wind turbine can be choose design variables of optimisation procedures

aiming at achieving satisfactory compromise among noise control, power production

and costs, so as to make wind energy quieter and cheaper (Hansen, 2008).

2.4 BLADE PLAN SHAPE AND QUANTITY

The ideal strategy form of a HAWT rotor blade is defined using the BEM method by

manipulative the chord length according to Betz limit, local air velocities and

aerofoil lift. Several theories exist for calculating the optimum chord length which

range in complexity. For blades with tip speed ratios of six to nine utilising aerofoil

sections with negligible drag and tip losses, Betz’s momentum theory gives a good

approximation. In instances of low tip speeds, high drag aerofoil sections and blade

sections around the hub, this method could be considered inaccurate. The Betz

method gives the basic shape of the modern wind turbine blade.

Figure 2.15 However, in practice more advanced methods of optimization are often

used (Schubel & Crossley, 2012).

2.5 ANGLE OF TWIST

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The lift generated by an aerofoil section is a function of the angle of attack to the

inflowing air stream. The inflow angle of the air stream is dependent on the

rotational speed and wind speed velocity at a specified radius. The angle of twist

required is dependent upon tip speed ratio and desired aerofoil angle of attack.

Generally the aerofoil section at the hub is angled into the wind due to the high ratio

of wind speed to blade radial velocity. In contrast the blade tip is likely to be almost

normal to the wind (Valencia, 2004).

The total angle of twist in a blade maybe reduced simplifying the blade shape to cut

manufacturing costs. However, this may force aerofoils to operate at less than

optimum angles of attack where lift to drag ratio is reduced. Such simplifications

must be well justified considering the overall loss in turbine performance.

2.6 WINGS AND LIFT

When a blade as a passes through air, the leading edge of the wing the airflow is

divides. Certain air goes over the top of the wings the rest goes underneath.

The air passing under the wing continues on more or less a straight line. This is

because the lower surface of the wing is almost flat. However, the air flowing over

the wing has farther to go, because the upper surface is curved. To keep up with the

air underneath, the air on top has to move faster. But by Bernoulli's principle, higher

speed means lower pressure. As a result, the air on top of the wing must press less

strongly against the wing than does the air underneath.

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Figure 2.16 The high and low high pressure on blade can provide the LIFT

(Darling, 2000).

Since the downward pressure on the top of the moving wing is less than the upward

pressure on the bottom of the wing, there is an overall upward force. This upward

force is called LIFT.

2.7 WIND SPEED

The wind speed data was taken and been analyze at the certain place in Malaysia

such as at Kudat, Labuan (Sabah) and Petaling Jaya (Selangor). The data was taken

from 2006 to 2008 and the crucial outcomes from this analysis are (M.R. Islama,

2011).

The monthly and yearly highest mean wind speeds were 4.76 m/s at

Kudat and 3.39 m/s at Labuan respectively.

The maximum wind power density was found to be 67.40 W/m2 at

Kudat for the year 2008.

The maximum wind energy density was found to be 590.40 kWh/m2/

year at Kudat in 2008.

The highest most probable wind speed and wind speed carrying

maximum energy were estimated 2.44 m/s at Labuan in 2007 and 6.02

m/s at Kudat in 2007.

The maximum deviation, at wind speed more than 2 m/s

29

Small scale wind energy can be generated at the turbine height of 100 m. At very low

wind speeds the turbine produces too little torque to overcome friction. Once the

wind speed is sufficient to allow the turbine to rotate, the output power is

approximately proportional to the cube of the wind speed. This remains true up to the

rated speed. Above this speed the power production levels off, and with stall

regulated turbines actually drops as wind speeds are increased. Finally at an even

higher wind speed, the furling speed, the turbine is shut down to avoid damage to the

machine (Othman, 2010).

During this time, the total wind speed can reach until 12m/s. The electricity

generation needs at least 4 to 4.5 m/s or 9 to 10.2 mph of total wind speed. Generally,

Malaysia wind is relatively calm for almost 30% to 50% of the year (Yusoff, 2006).

At this time the highest mean daily wind speed 3.8 m/s recorded Mersing, Johor. For

highest maximum wind speed 41.7 m/s is recorded at Kuching, Sarawak on 15

September 1992. This data collected from Ministry of Science, Technology and

Innovation (MOSTI).

Figure 2.17 Peninsula of Malaysia

2.8 ALUMINIUM BLADE

Aluminium is a silvery white metal with a density about a third that of steel.

Aluminum was only implemented in testing situations because it was found to have a

lower fatigue level than steel. Aluminium is ductile and good heat conductor.

Aluminium is a low price metal but it has good reliability and has a low tensile

strength. Aluminum is lightweight, but weaker and less stiff than steel.

30

Properties of Aluminium has a unique and unbeatable combination of properties that

make it into a versatile, highly usable and attractive construction material.

Aluminium is light with a density one third that of steel, 2.700 kg/m3. This material

also strong with a tensile strength of 70 to 700 MPa depending on the alloy and

manufacturing process. Extrusions of the right alloy and design are as strong as

structural steel. The Young’s modulus for aluminium is a third that of steel (E =

70,000 MPa). This means that the moment of inertia has to be three times as great for

an aluminium extrusion to achieve the same deflection as a steel profile.

Aluminium blades have many advantages over other blade materials:

Improved strength and rigidity.

Better sheer strength at mounting points.

Not UV affected, long life compared to PVC or wood.

Easier and cheaper to paint, could be used unpainted with leading edge

tape.

More uniform aerofoil.

End caps are held with 4 small screws.

By using small rod in the C channel in the ends allows easy balancing.

Slightly lighter than PVC.

100% aluminium, recyclable.

31

CHAPTER 3

METHODOLOGY

3.1 INTRODUCTION

For this chapter to explain about methodology and the development of process.

Before starts this project, student should know and identify the method of project

methodology. This chapter must include in report because to identify step by step on

how the flow or progress of the project will be too successful. A lot of journal,

books, report, newspaper, website and the other to determine about wind turbine that

currently use in worldwide we can refer. If use the wind turbine we should know

about the wind, because the wind must has high wind speed velocity, but in Malaysia

is country that have low wind speed velocity. Therefore, the student has a create

ideas and brainstorming to design and find the best material blades wind turbine due

to uncertainty wind speed in Malaysia.

3.2 DESIGN PROCESS

In design process to show the steps that need to follow from start until end steps.

Starting the design brief about wind turbine blades, it show a little defect or lack and

need to be improving in order to give successful product. More idea and

brainstorming required to get the solution for the problem. This process also can be

identifying the problem design. To know what material and design for suitable, an

analyzed must was done. Modification or refinement can be made to the concept

while certain steps are common in the development of most product design..

32

Design brief

Identify the criteria

Solve the solution

Generate idea

Brainstorming

Conceptual design

Concept (drawing)

Refine the design

Select the best design

Detail design

Detail product

Detail manufacture

Manufacturing instruction

Figure 3.1 Design Process

33

3.3 DEVELOPMENT METHODOLOGY

This flow representation can give a stage explanation to a given problem. The arrows

connecting them represent flow/direction of flow of data. In figure 3.2 below shows

flowchart that was used to complete the design and development project.

Figure 3.2 Mechanism and analysis proces flow chart

34

Brainstorming

Research

Literature review

Problem statement

Customer requirement

Technical requirement

Generate product concept

Design

Conceptual designMaterial selction

Design approva

l

Analysis

Prototype

Testing

Final product

Troubleshoot/

Rework

Specification

YES

NO

Establish target specification

3.4 GANTT CHART

This Gantt chart is basically plan to control and helps student to follow the

prescribed task without wasting time unnecessarily. It also management for each task

and make a fabrication process going smoothly. In the other words, project schedule

can make a task going systematically and also can avoid mistake throughout the

process.

35

Figure 3.3 Gantt Char

37

3.5 CUSTOMER REQUIREMENT

Before the concept to be developed, the list of customer needs is made with group

discussion and also interviews to get customer need about the product to be

developed. The needs of the identify customer is for largely independent of any

particular product and not specification to the concepts of the choose product. Other

terms is including customer attributes and customer requirement. Its helps and guide

a designer to create a product using criteria needed.

3.5.1 Identifying Customer Needs

Method used in this research is:

i. Library research/Internet

ii. Questionnaire

iii. Focus group

Customer Requirements RankingsGS

Aerodynamic 5

Easy to operate 3

Smooth and silent 3

Lightweight 4

Stability 4

Durable 5

Attractive 3

Easy to install 3

Quality 4

Minimize vibration 3

Improve energy capture 5

Figure 3.4 Customer Needs

38

Rankings:

1. Feature is undesirable, a product/ process with this feature should not be

considered.

2. Feature is not important, but would be ok to have.

3. Feature would be nice to have, but is not necessary.

4. Feature is highly desirable, a product/ process without it should be

considered.

5. Feature is critical, a product/ process without this feature should not be

considered.

3.5.2 Research Methodology for Establish Specification

Method used in this research is:

i. Quality Function Deployment (QFD)

ii. Product Design Specification (PDS)

a) Quality Function Deployment (QFD)

Quality Function Deployment (QFD) is a customer driven planning process

to guide the design, manufacturing, and marketing of goods. Through QFD,

every design, manufacturing, and control decision is made to meet the

expressed needs of customers. It uses a type of matrix diagram to present data

and information. Under QFD, all operations of a company are driven by the

voices of the customer, rather than by edicts of top management or the

opinions or desires of design engineers.

39

Strong (9) Medium (4) Weak (1)

Figure 3.5 Quality Function Deployment (QFD)

b) Product Design Specification (PDS Diagram)

A product design specification (PDS Diagram) is a statement of what a not

yet designed product is intended to do. Its aim is to ensure that the subsequent

design and development of a product meets the needs of the user. The PDS

Diagram acts as an initial boundary in the development of products.

40

Figure 3.6 PDS Diagram

c) Sketching Product Concept

For these steps, a sketch is a rapidly executed freehand drawing that is not intended

as a finished work. Figure below shows the sketching done by the student for blade

and hub design of wind turbine.

Concept 1 Concept 2

Concept 3 Concept 4

Concept 5

Figure 3.7 Concepts of Blades Design

42

Concept 1 Concept 2

Concept 3 Concept 4

Concept 5

Figure 3.8 Concepts of Hub Design

3.6 CONCEPT SELECTION

43

3.6.1 Introduction

Concept selection is the process of evaluating concepts with respect to customer

needs and other criteria, comparing the relative strengths and weakness of the

concepts, and selecting one or more concepts for further investigation, testing, or

development.

Concept selection is an iterative process closely related to concept generation and

testing. The concept screening and scoring methods help the team refine and improve

the concepts, leading to one or more promising concepts upon which further testing

and development activities will be focused. In concepts selection involves two-stage

methodology is a:

i. Concepts screening

ii. Concept scoring

3.6.2 Concept Screening

The purpose of this stage are to narrow the number of concepts quickly and to

improve the concepts. To complete this stage, must have five step:

1) Prepare the selection matrix

2) Rate the concept

3) Rank the concept

4) Combine and improve the concept

5) Select one or more concept

44

Figure 3.9 Concept Screening

3.6.3 Concept Scoring

Concept scoring is used when increased resolution will better differentiate among

competiting concept. In this stage, our team weight the relative importance of the

selection criteria and focuses on more refined comparisons wtih respect to each

criterion. The concept scores are determined by the weighted sum of the ratings.

Table 5.2 illustrates the scoring matrix used in this stage. In describing the concept

process, we focus on differences relative to concept scoring.

45

Figure 3.10 Concept Scoring

3.7 RESULT ANALYSIS FOR BLADE

3.7.1 Catia Drawing

In this process, catia is the method for doing a detail drawing. Each parts in blade

design for small scale wind turbine was drawn and final secifications was

determined. The model of wind turbine blades of different thickness by using

mechanical packages (CATIA). Blade design are devided into two parts which are:

i. Blade

ii. Hub

Figure 3.11 Concept 5 drawing (Blade)

46

3.7.2 Properties of Fiber Glass and Aluminium

Table 3.1 Properties of Fiber Glass and Aluminium.

Material PropertiesF

iber

Gla

ss

Modulus of Elasticity 45 GPa

Modulus of elasticity -

Mass Density 2080 kg/m3

Specific Weight 18.5 kN/m3

Poisson’s Ratio 0.22

Yield Stress 54.4 MPa

Ultimate Stress 80.9 MPa

Alu

min

ium

Modulus of Elasticity 70 GPa

Modulus of elasticity 10 psi

Mass Density 2710 kg/m3

Specific Weight 26.6 kN/m3

Poisson’s Ratio 0.35

Yield Stress 20 MPa

Ultimate Stress 70 MPa

47

3.7.3 Wind turbine blade design and performance analysis

The research activities in this area aim to provide the guidance for the design

optimization of wind turbine blades through investigating the design methods and

analysing the performance of the blades.

Figure 3.12 Analysis by using Hypermesh

For project analysis, HyperMesh software has been used. This software is to

determine stress, strain and displacement of blade. Have two type materials for

blades and two forces different to analyzed.

Most modern wind turbine blades are made from glass-fibre reinforced polymer

(GRP) composites due to their light weight and good mechanical properties. Once

the geometric shape of the wind turbine blade is determined, the mechanical

performance of the blade is mainly determined by the lay-up scheme, which includes

the thickness distribution and fibre direction of the composites. Through stress-strain

analysis of different lay-up structures using HyperMesh software.

48

Figure 3.13 Force 2 newton and constraint apply on blade.

Table 3.2 Result displacement and stress when apply force 2N on blade.

Forces 2N

MaterialThickness

(mm)

Displacements

(mm)

Yield

Stress

(N/mm2)

Stress

(N/mm2)

Fib

er G

lass 3 Max =1.114 ×101

54.4

Max =1.381×101

4 Max = 4.733 Max = 7.411

5 Max = 2.442 Max = 4.740

Alu

min

ium

3 Max =7.135 ×10−3

20

Max = 1.430 ×101

4 Max =3.03 ×10−3 Max = 7.603

5 Max =1.566 ×10−3 Max = 4.818

49

Figure 3.14 Force 5 newton and constraint apply on blade.

Table 3.3 Result displacement and stress when apply force 5N on blade.

Forces 5N

MaterialThickness

(mm)

Displacements

(mm)

Yield

Stress

(N/mm2)

Stress

(N/mm2)

Fib

er G

lass

3 Max =2.749 ×101

54.4

Max =3.431 ×101

4 Max =1.168 ×101 Max =1.842×101

5 Max = 6.029 Max =1.178 ×101

Alu

min

ium

3 Max =1.756 ×101

20

Max =3.631 ×101

4 Max = 7.471 Max =1.927 ×101

5 Max = 3.858 Max =1.213 ×101

50

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54

55

APPENDIX A

1. Do you think the wind turbine help lower your energy problem?

Yes

No

2. What part you want to improve for generate more energy?

Blades

Generator

3. What do you expect from wind turbine blades?

Attractive

Good aerodynamic

Material selection

Other:

. .

4. What type material of wind turbine blades that you need?

Wood

Composite

Alluminium

5. What is the most important criteria of that wind turbine blade should have?

Lightweight

Smooth and silent

Cost

Durable

Easy to install

6. What is your suggestion to improve the energy capture of wind turbine?

56