Major project report part ii

1 | P a g e

A

Major Project report

on

“Generation of electricity from exhaust hot gases”

Submitted for partial fulfillment of award of

Of

BACHELOR OF TECHNOLOGY

Degree

In

Mechanical Engineering

Under the Supervision of

Mr. Bhupendra Gahlot

By

Sonu Choudhary (K10201)

Pradeep Kumar Mahato(K10458)

Nandan Yadav (K10230)

Harsh Wardhan Kumar (K10016)

To

Career Point University, Kota

May 2016

2 | P a g e

CERTIFICATE

This is to certify that report entitled “Electricity generation from exhaust hot

gases”which is submitted by Sonu Choudhary(K10201), Pradeep Kumar Mahato

(K10458), Nandan Yadav (K10230), Harsh Wardhan Kumar (K10016) in partial

fulfillment of the requirement for the award of degree B.Tech in Mechanical Engineering

to Career Point University, Kota is a record of the candidates’ own work carried out by

them under my supervision. The matter embodied in this report is original and has not

been submitted for the award of any other degree anywhere else.

Date: Supervisor

3 | P a g e

ACKNOWLEDGEMENT

We would like to express our heartfelt gratitude to our guide Mr. Bhupendra Gahlot,

Assistant Professor Department of Mechanical Engineering for his valuable time and

guidance that made the project work a success. He has inspired us with such a spirit of

devotion, precision and unbiased observation, which is essentially a corner stone of

technical study. We are highly grateful to Professor Dr. Sudhakar Rawat (DEAN OF

CAREER POINT UNIVERSITY, KOTA) for their kind support for the project work. We

thank all our friends and all those who have helped us carrying out this work directly or

indirectly without whom completion of this project work was not possible.

We would also like to sincerely thank Vice-chancellor, Dr. Mithilesh Dixit of Career

Point University, and Kota for giving us a platform to carry out the project.

Yours Sincerely,

SONU CHOUDHARY(K10201)

PRADEEP MAHATO(K10458)

NANDAN YADAV(K10230)

HARSH WARDHAN(K10016)

4 | P a g e

TABLE OF CONTENTS

Title……………………………………………………….Pg. No.

List of Figures……………………………………………………………………... 6

Abstract……………………………………………………………………………..8

1.Introduction……………………………………………………………………. 9

2.Engines and Exhaust System …………………………………………………11

2.1 Engine working and Types…………………………………………………....11

2.2 Exhaust Systems……………………………………………………………….12

2.3 Project Modifying Exhaust System …………………………………… .13

3. Reaction Turbine………………………….................................................14

3.1 Operation Theory of Reaction Turbine ………………………………………16

3.2 Comparison of Reaction and Impluse turbine…………………………………19

3.3 Project Modifying Turbine ………………………………………………… 20

4. Backward Curved Turbine…………………………………………………....21

4.1 Backward Turbine Working………………………………………………..… 21

4.2 Backward Curved Turbine Fan and Design…………………………………... 22

4.3 Project Modifying Turbine …………………………………………………... 25

5 | P a g e

5.Mechanical Shaft, Bearings and casing……………………………………26

5.1 Mechanical Shaft…………………………………………………………...26

5.1.1 Shaft Designing Process………………………………………………... 27

5.2 Bearings ……………………………………………………………….…. 30

5.2.1 Fixing of bearings………………………………………………………..30

5.2.2 Bearing fitting dimensions ……………………………………………….31

5.3 Casing……………………………………………………………………...34

5.3.1 Casing Design ……………………………………………………………35

6. Electricity Generator……………………………………………………….35

6.1 Electricity Generator Working……………………………………………. 36

6.2 Specification of Used Electricity Generator……………………………… 38

7. Flywheel…………………………………………………………………… 38

7.1 Flywheel Design……………………………………………………………39

8. Summary………………………………………………………………..… 42

9.References…………………………………………………………..…….. .43

6 | P a g e

LIST OF FIGURES

S. No. Fig. No. Description Pg. No.

1. Fig -1 Total Fuel Energy Content in I. C. Engine 10

2. Fig-2 Internal Combustion Engine 11

3. Fig-3 Exhaust Manifold (chrome plated) on a Car Engine 12

4. Fig-4 Various Type of Bike Exhaust Mufflers 13

5. Fig-5 Layout of Exhaust System with Electrical Generator 13

6. Fig-6 Reaction Turbine 15

7. Fig-7 Reaction Turbine Cross Section View 16

8. Fig-8 Reaction Turbine with Curved Blades 16

9. Fig-9 Axial Flow Fan Rotor Wheel 21

10. Fig-10 Axial Flow Fan Direction of Air Flow 21

11. Fig-11 Centrifugal Fan Impeller Wheel 22

12. Fig-12 Centrifugal Fan Direction of Airflow 22

13. Fig-13 Impeller Vector Diagrams 23

14. Fig-14 Forward Curved Impeller Wheel 23

15. Fig-15 Backward Curved Impeller Wheel 23

16. Fig-16 Characteristic Performance Curve of a Backward Curved

Centrifugal Fan 24

17. Fig-17 Mechanical shaft for Exhaust system 26

18. Fig-18 Dimensioning of Bearing 32

19. Fig-19 Bearing Mounting spacer 33

20. Fig-20 Thrust bearings and fitting 34

21. Fig-21 Roller bearing and Fitting 34

22. Fig-22 Outer Casing design 35

23. Fig-23 Configurations of Electricity generators 37

24. Fig-24 DC Generator 38

25. Fig-25 Automotive Flywheel 39

26. Fig-26 Two dimensional representation of shaft with Flywheel 39

27. Fig-27 Flywheel Geometry 40

7 | P a g e

LIST OF TABLE

S. No. Table Description Pg. No.

1. Table No.-1 Various Engine and There Output 10

2 Table No.-2 Comparison between Reaction and Impulse

turbine

20

3 Table No.-3 General Bearing Fixing Method 31

4 Table No.-4 Fixing methods for bearings with tapered

bores

31

5 Table No.-5 Fillet Radius and abutment height 32

6 Table No.-6 Relief dimensions for ground shaft 33

7 Table No.-7 Shaft and housing accuracy 34

8 | P a g e

ABSTRACT

A novel concept for an air pressure-driven micro-turbine is proposed in this paper.

Turbine and generator are embedded in one single component, thus eliminating coupling

losses and misalignment issues, and improving compactness, reliability and lifetime.The

machine is a multi-stage axial reaction turbine with a backward curved turbine for high

discharge rate. Two prototypes of the micro-turbine were built. The first one was a not

fully optimized prototype for concept proofing while the second one was designed to

optimize the fluid dynamic efficiency minimizing the air consumption. In the second

prototype the air flow can reach speeds up to 100000 rpm (with 2.4 bar of supply

absolute pressure) and produces, when coupled to a small generator, a maximum

electrical power of 13W. The maximum total efficiency is around 4% in the optimal

condition while the maximum turbine efficiency is around 50% It will improve engine

performance and fuel economy by outlet pressure drop. If the discharge rate will be high

then engine can breathe quickly and easily so good breathing will come out as

performance, fuel economy and long life engine with low maintenance. This mechanism

will be installed in exhaust system. It will be a mechanism of axial high pressure turbine

and backward curved turbine with an electrical generator. The air will strike on high

pressure reaction turbine and the pressure energy will convert into mechanical energy.

This shaft will also be rotate backward curved turbine that will increase the discharge

rate. The electrical generator will rotated by the same shaft and the electricity will be

produce by generator.

9 | P a g e

1. INTRODUCTION

We are having a very wide industry of Automobile sector. Recent trend about the best

ways of using the deployable sources of energy in to useful work in order to reduce the

rate of consumption of fossil fuel as well as pollution. Out of all the available sources, the

internal combustion engines are the major consumer of fossil fuel around the globe. Out

of the total heat supplied to the engine in the form of fuel, approximately, 30 to 40% is

converted into useful mechanical work. The remaining heat is expelled to the

environment through exhaust gases and engine cooling systems, resulting in to entropy

rise and serious environmental pollution, so it is required to utilized waste heat into

useful work. The recovery and utilization of waste heat not only conserves fuel, usually

fossil fuel but also reduces the amount of waste heat and greenhouse gases damped to

environment. It is imperative that serious and concrete effort should be launched for

conserving this energy through exhaust heat recovery techniques. Such a waste heat

recovery would ultimately reduce the overall energy requirement and also the impact on

global warming.

The Internal Combustion Engine has been a primary power source for automobiles and

automotives over the past century. Presently, high fuel costs and concerns about foreign

oil dependence have resulted in increasingly complex engine designs to decrease fuel

consumption For example, engine manufacturers have implemented techniques such as

enhanced fuel-air mixing, turbo-charging, and variable valve timing in order to increase

thermal efficiency.

However, around 60-70% of the fuel energy is still lost as waste heat through the coolant or the

exhaust. Moreover, increasingly stringent emissions regulations are causing engine

manufacturers to limit combustion temperatures and pressures lowering potential efficiency gains

[1]. As the most widely used source of primary power for machinery critical to the

transportation, construction and agricultural sectors, engine has consumed more than 60% of

fossil oil. On the other hand, legislation of exhaust emission levels has focused on carbon

monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and particulate matter (PM).

conversion efficiency for reducing both the fuel consumption and emissions of engine, scientists

10 | P a g e

and engineers have done lots of successful research aimed to improve engine thermal efficiency,

including supercharge, lean mixture combustion, etc. However, in all the energy saving

technologies studied. Engine exhaust heat recovery is considered to be one of the most effective.

Many researchers recognize that Waste Heat Recovery from engine exhaust has the potential to

decrease fuel consumption without increasing emissions, and recent technological advancements

have made these systems viable and cost effective [3]. This paper gives a comprehensive review

of the waste heat from internal combustion engine, waste heat recovery system and methods of

waste heat recovery system[1].

Fig -1 Total Fuel Energy Content in I. C. Engine

Table No.-1 Various Engine and There Output

11 | P a g e

2. ENGINE AND EXHAUST SYSTEM

2.1 Engine Working and Types

The internal combustion engine is an engine in which the combustion of fuel and an

oxidizer (typically air) occurs in a confined space called a combustion chamber. This

exothermic reaction creates gases at high temperature and pressure, which are permitted

to expand. Internal combustion engines are defined by the useful work that is performed

by the expanding hot gases acting directly to cause the movement of solid parts of the

engine.The term Internal Combustion Engine (ICE) is often used to refer to an engine in

which combustion is intermittent, such as a Wankel engine or a reciprocating piston

engine in which there is controlled movement of pistons, cranks, cams, or rods. However,

continuous combustion engines such as jet engines, most rockets, and many gas turbines

are also classified as types of internal combustion engines. This contrasts with external

combustion engines such as steam engines and Stirling engines that use a separate

combustion chamber to heat a separate working fluid—which then in turn does work, for

example, by moving a piston or a turbine[2].

Fig-2 – Internal Combustion Engine

12 | P a g e

A huge number of different designs for internal combustion engines exist, each with

different strengths and weaknesses. Although they're used for many different purposes,

internal combustion engines particularly see use in mobile applications such as cars,

aircraft, and even handheld applications.

2. 2 Exhaust System

An exhaust system is usually piping used to guide reaction exhaust gases away from a

controlled combustion inside an engine or stove. The entire system conveys burnt gases

from the engine and includes one or more exhaust pipes. Depending on the overall

system design, the exhaust gas may flow through one or more of:

Cylinder head and exhaust manifold

A turbocharger to increase engine power.

A catalytic converter to reduce air pollution.

A muffler (North America) / silencer (Europe), to reduce noise [2]

Fig -3 Exhaust Manifold (chrome plated) on a Car Engine

13 | P a g e

Fig-4 Various Type of Bike Exhaust Mufflers

2.3 Project Modifying Exhaust System

The exhaust system design plays very important role in heat removing process. The

exhaust designed in such a way that it can remove maximum heat at maximum discharge

rate with lower sound. The exhaust system also clogged with a circular plate so the

pressure can be increase and air will strike only the turbine blades and we can get

maximum output from the system.

Fig -5 Layout of Exhaust System with Electrical Generator

14 | P a g e

3. Reaction Turbine

Reaction turbines are those turbines which operate under hydraulic pressure energy and

part of kinetic energy. In this case, the water reacts with the vanes as it moves through the

vanes and transfers its pressure energy to the vanes so that the vanes move in turn

rotating the runner on which they are mounted.

The main types of reaction turbines are as following

1. Radially outward flow reaction turbine: This reaction turbine consist a cylindrical

disc mounted on a shaft and provided with vanes around the perimeter. At inlet the water

flows into the wheel at the center and then glides through radially provided fixed guide

vanes and then flows over the moving vanes. The function of the guide vanes is to direct

or guide the water into the moving vanes in the correct direction and also regulate the

amount of water striking the vanes. The water as it flows along the moving vanes will

exert a thrust and hence a torque on the wheel thereby rotating the wheel. The water

leaves the moving vanes at the outer edge. The wheel is enclosed by a water-tight casing.

The water is then taken to draft tube [3].

2. Radially inward flow reaction turbine: The constitutional details of this turbine are

similar to the outward flow turbine but for the fact that the guide vanes surround the

moving vanes. This is preferred to the outward flow turbine as this turbine does not

develop racing. The centrifugal force on the inward moving body of water decreases the

relative velocity and thus the speed of the turbine can be controlled easily.

The main component parts of a reaction turbine are:

(a) Casing, (b) Guide vanes (c) Runner with vanes (d) Draft tube

a) Casing: This is a tube of decreasing cross -sectional area with the axis of the tube

being of geometric shape of volute or a spiral. The water first fills the casing and then

enters the guide vanes from all sides radially inwards. The decreasing cross -sectional

area helps the

velocity of the entering water from all sides being kept equal. The geometric shape helps

the entering water avoiding or preventing the creation of eddies.

b) Guide vanes: Already mentioned in the above sections.

15 | P a g e

c) Runner with vanes: The runner is mounted on a shaft and the blades are fixed on the

runner at equal distances. The vanes are so shaped that the water reacting with the m will

pass through them thereby passing their pressure energy to make it rotate the runner.

d) Draft tube: This is a divergent tube fixed at the end of the outlet of the turbine and the

other end is submerged under the water level in the tail race. The water after working on

the turbine, transfers the pressure energy there by losing all its pressure and falling below

atmospheric pressure. The draft tube accepts this water at the upper end and increases its

pressure as the water flows through the tube and increases more than atmospheric

pressure before it reaches the tailrace.

3. Mixed flow reaction turbine: This is a turbine wherein it is similar to inward flow

reaction turbine except that when it leaves the moving vane, the direction of water is

turned from radial at entry to axial at outlet. The rest of the parts and functioning is same

as that of the inward flow reaction turbines.

4. Axial flow reaction turbine: This is a reaction turbine in which the water flows

parallel to the axis of rotation. The shaft of the turbine may be either vertical or

horizontal. The lower end of the shaft is made larger to form the boss or the hub. A

number of vanes are fixed to the boss. When the vanes are composite with the boss the

turbine is called propeller turbine. When the vanes are adjustable the turbine is called a

Kaplan turbine[3].

Fig-6 Reaction Turbine

16 | P a g e

Fig-7 Reaction Turbine Cross Section View

3.1 Operation Theory of Reaction Turbine

A working fluid contains potential energy (pressure head) and kinetic energy (velocity

head). The fluid may be compressible or non-compressible. Several physical principles

are employed by turbines to collect this energy. Silicon nitride turbine wheel for use in

small turbo generators. Impulse turbines change the direction of flow of a high velocity

fluid jet [4].

Fig-8 Reaction Turbine with Curved Blades

17 | P a g e

The resulting impulse spins the turbine and leaves the fluid flow with diminished kinetic

energy. There is no pressure change of the fluid in the turbine rotor blades. Before

reaching the turbine the fluid's Pressure head is changed to velocity head by accelerating

the fluid with a nozzle. Pelton wheels and de Laval turbines use this process exclusively.

Impulse turbines do not require a pressure casement around the runner since the fluid jet

is prepared by a nozzle prior to reaching turbine. Newton’s second law describes the

transfer of energy for impulse turbines. Reaction turbines develop torque by reacting to

the fluid's pressure or weight.

The pressure of the fluid changes as it passes through the turbine rotor blades. A pressure

casement is needed to contain the working fluid as it acts on the turbine stage(s) or the

turbine must be fully immersed in the fluid flow (wind turbines). The casing contains and

directs the working fluid and, for water turbines, maintains the suction imparted by the

draft tube. Francis turbines and most steam turbines use this concept. For compressible

working fluids, multiple turbine stages may be used to efficiently harness the expanding

gas. Newton’s third law describes the transfer of energy for reaction turbines [4].

Turbine designs will use both these concepts to varying degrees whenever possible. Wind

turbines use a foil to generate lift from the moving fluid and impart it to the rotor (this is

a form of reaction), they also gain some energy from the impulse of the wind, by

deflecting it at an angle. Cross flow turbines are designed as an impulse machine, with a

nozzle, but in low head applications maintain some efficiency through reaction, like a

traditional water wheel. Gas turbines with multiple stages have the first stage reacting to

impulse of the gas flow (because it is inefficient to increase the velocity when it is almost

at the speed of sound) and later stages being designed for reaction in the decreasing

velocity flow. Blades in many stages being arranged to be reaction over some parts (of

their length) and impulse over the rest.

Classical turbine design methods were developed in the mid-19th century. Vector

analysis related the fluid flow with turbine shape and rotation. Graphical calculation

methods were used at first. Formulas for the basic dimensions of turbine parts are well

documented and a highly efficient machine can be reliably designed for any fluid flow

condition. Some of the calculations are empirical or 'rule of thumb' formulae and others

18 | P a g e

are based on classical mechanics. As with most engineering calculations, simplifying

assumptions were made [4].

Velocity triangles can be used to calculate the basic performance of a turbine stage. Gas

exits the stationary turbine nozzle guide vanes at absolute velocity Va1. The rotor rotates

at velocity U. Relative to the rotor; the velocity of the gas as it impinges on the rotor

entrance is Vr1. The gas is turned by the rotor and exits, relative to the rotor, at velocity

Vr2. However, in absolute terms the rotor exit velocity is Va2. The velocity triangles are

constructed using these various velocity vectors. Velocity triangles can be constructed at

any section through the blading (for example: hub, tip, midsection and so on) but are

usually shown at the mean stage radius. Mean performance for the stage can be

calculated from the velocity triangles, at this radius, using the Euler equation:

Hence:

Where: Acceleration of gravity

Enthalpy drop across stage

Turbine entry total (or stagnation) temperature

Turbine rotor peripheral velocity

Delta whirl velocity

The turbine pressure ratio is a function of and the turbine efficiency. Modern

turbine design carries the calculations further. Computational fluid dynamics dispenses

with many of the simplifying assumptions used to derive classical formulas and computer

software facilitates optimization. These tools have led to steady improvements in turbine

design over the last forty years.

The primary numerical classification of a turbine is its specific speed. This number

describes the speed of the turbine at its maximum efficiency with respect to the power

and flow rate. The specific speed is derived to be independent of turbine size. Given the

19 | P a g e

fluid flow conditions and the desired shaft output speed, the specific speed can be

calculated and an appropriate turbine design selected.

The specific speed, along with some fundamental formulas can be used to reliably scale

an existing design of known performance to a new size with corresponding performance.

Off-design performance is normally displayed as a turbine map or characteristic [4].

3.2 Comparison of Reaction turbine and Impulse Turbine

3.2.1 Axial flow turbines

If the water flows parallel to the axis of the rotation of the shaft, the turbine is known

as axial flow turbine.

If the head at the inlet of the turbine is the sum of pressure energy and kinetic energy

and during the flow of water through runner a part of pressure energy is converted into

kinetic energy, the turbine is known as reaction turbine.

For the axial flow reaction turbines, the shaft of the turbine is vertical. The lower end

of the shaft is made larger which is known as hub. The vanes are fixed on the hub and

hence hub acts as runner for axial flow reaction turbine.

The following are the important type of axial flow turbines:

1. Propeller turbine

2. Kaplan turbine

When the vanes are fixed to the hub and they are not adjustable, the turbine is known

as propeller turbine.

If vanes on hub are adjustable the turbine is known as a Kaplan turbine. This turbine

is suitable where a large quantity of water at low heads is available.

20 | P a g e

Difference between Impulse and Reaction turbine

Impulse Turbine Reaction turbine

The entire available energy of the water is

Converted into kinetic energy. Only a portion of the fluid energy is

converted into kinetic energy before the

fluid enters the turbine runner.

The work is done only by the change in the

Kinetic energy of the jet. The work is done partly by the change in

the velocity head, but almost entirely by

the change in pressure head.

Flow regulation is possible without loss. It is not possible to regulate the flow

without loss.

Unit is installed above the tailrace. Unit is entirely submerged in water below

the tailrace

Casing has no hydraulic function to

perform, because the jet is unconfined and

is at atmospheric pressure. Thus, casing

serves only to prevent splashing of water.

Casing is absolutely necessary, because the

Pressure at inlet to the turbine is much

higher than the pressure at outlet. Unit has

to be sealed from atmospheric pressure.

It is not essential that the wheel should run

full and air has free access to the buckets

Water completely fills the vane passage.

Table No.-2 Comparison between Reaction and Impulse turbine

3.3 Project Modifying Turbine

We will use high pressure reaction turbine with axial flow. We will get axial flow from

the exhaust system so axial flow turbine will be most efficient turbine. The working fluid

is air so the reaction turbine is better than palton or impulse turbine. The reaction turbine

is also give maximum efficiency on low pressure working fluid. As we know that engine

exhaust gasses not have high much pressure to our purpose reaction turbine will be

fruitful to us. This turbine is easily made by CNC machines as per our dimensions. We

can design it according our purpose. The reaction turbine is also having 1 degree of

freedom. We can use it in multi stage for axial flow to achieve maximum efficiency and

maximum mechanical work from the turbine. The best turbine for our use is reaction

turbine 2 stage multi turbines with variable guide vanes we will use in our working

model.

21 | P a g e

4. Backward Curved Turbine

4.1 Backward Turbine Working

Axial Flow and Centrifugal Fans an axial flow fan propels air in an axial direction,

parallel to the fan’s shaft, with a swirling tangential motion created by the rotating

impeller blades. The air velocity is increased through rotational force, which produces

velocity pressure (kinetic energy) and a small amount of static pressure (potential

energy). Axial flow fans are well suited for applications that require moving large

quantities of air with low static pressure requirements, such as for condensers, exhaust

applications, spot cooling and boosting airflow through long ductwork. The rotor wheel

of an axial flow fan is shown in Fig. , the direction of airflow is shown in Fig. 10. A

centrifugal fan propels air in a radial direction, perpendicular to the fan’s shaft. Airflow is

induced by the centrifugal force generated in a rotating column of air, producing static

pressure (potential energy), and by the rotational velocity imparted to the air as it leaves

the tip of the blades, producing velocity pressure (kinetic energy). This makes centrifugal

fans well suited for air movement applications requiring medium to high static pressure

capabilities and low noise requirements such as supply and return fans. The impeller

wheel of a centrifugal fan is shown in Fig. 11, the direction of airflow is shown in Fig. 12

Fig-9 Axial Flow Fan Rotor Wheel Fig-10 Axial Flow Fan Direction of Air Flow

22 | P a g e

Fig-11 Centrifugal Fan Impeller Wheel Fig-12 Centrifugal Fan Direction of Airflow

Forward and Backward Curved Fans

Centrifugal fans are the most common type of supply fans used in the HVAC industry.

The most common types of centrifugal fan impellers are the forward curved impeller and

the backward curved impeller. Backward curved, backward inclined and airfoil impellers

have similar performance curves and thus the following backward curved fan information

applies to backward inclined and airfoil fans, as well [6].

4.2 Backward Curved Turbine Fan and Design

Fig. 13 shows the vector diagrams of the forces from forward curved and backward

curved impeller blades. Vector V1 represents the rotational velocity, and vector V2

represents the radial velocity of the airflow between the blades. Vector R represents the

resultant velocity for each of these impeller blade types. Note that the magnitude of the

vector R for the forward curved impeller is greater than for the backward curved

impeller. Because the pressure produced by a fan is a function of the forward motion of

the air at the tip of the blade, a forward curved fan with a larger number of blades will

operate at a lower speed for a given duty than a backward curved fan. A forward curved

impeller wheel is shown in Fig. 14 and a backward curved impeller wheel is shown in

Fig. 15 [6].

23 | P a g e

Fig-13 Impeller Vector Diagrams

Fig.-14 Forward Curved Impeller Wheel Fig-15 Backward Curved Impeller Wheel

An attractive feature of the backward curved impeller is the non-overloading

characteristic of its horsepower curve. As Fig. 13 illustrates, the horsepower increases to

a maximum as airflow increases, and then drops off again toward free delivery. This

means that a motor selected to accommodate the peak horsepower will not overload,

overheat or burnout, despite variations in the system resistance or airflow, as long as the

fan speed remains constant. This is in contrast to the overloading tendency of the forward

curved blades, because backward curved fans operate at higher speeds for a given

pressure than forward curved fans, backward curved fans must be more sturdily

24 | P a g e

constructed than their forward curved counterparts. High speed operation and sturdy

construction also make the backward curved fan suitable for applications with higher

static pressure requirements, where a forward curved fan cannot be used. This

construction and capability will result in a greater first cost versus the forward curved

fan, however, this cost is most often offset by the higher backward curved fan’s operating

efficiency [7].

Fig-16 Characteristic Performance Curve of a Backward Curved Centrifugal Fan

The backward curved impeller can require up to 15% less power than forward curved

fans at the same duty requirements. Typical forward curved fan peak efficiencies are in

the range of 65 to 70%, while the backward curved impeller offers peak efficiencies

between 75 and 80%. This makes the backward curved impeller a good choice for any

application that benefits from higher efficiencies, such as large systems or those that

require the fan to be run for many hours. In these types of applications, any discrepancy

in first cost is quickly paid back by the lower operating cost as a result of the higher

operating efficiency.

25 | P a g e

4.3 Project Modifying Turbine

It is a high efficiency backward curved industrial fan designed for handling relatively

clean air in high pressure applications. Typical applications include combustion air,

product cooling, moisture blow-off, forced draft on fluid bed boilers, and induced draft

after bag-house process blowers. It have features a wider impeller and housing, producing

a high volume of air at a lower velocity, the need for an expansion ease is eliminated.

These types of fans are available with a variety of construction options and accessories,

offering the versatility and flexibility required in today's industrial applications.

Sizes

10 to 2260 mm impeller diameters

Performance

Airflow to 200 m3/sec at 500 Pa

Static pressure to 9945 Pa

Airstream temperatures to 425°C

Arrangements

1, 3SI, 4, 7SI, 8, 9 and 9F

Drive Configurations

Available in both direct and belt drive configurations.

Construction

• Design for tip speeds up to 70 m/s

• Design for tip speeds up to 85 m/s

• Design for tip speeds up to 110 m/s

• Design for tip speeds up to 130 m/s

Housings

Heavy-gauge, reinforced, continuously welded housings provide strength and durability

for extended service life — a necessity in all commercial and industrial installations.

Outlet flanges for duct-connection as well as rigidity are standard. Inlet collars for slip-

joint connection and lifting lugs are also standard. All housings are reinforced with rigid

bracing to increase structural integrity. The support angles are intermittently welded and

caulked between welds to prevent bleed-through corrosion. Precisely positioned cutoff

plates and aerodynamically spun inlet cones provide high efficiency and smooth airflow

through the fan [7].

26 | P a g e

5. Mechanical Shaft, Bearings and casing

5.1 Mechanical Shaft

Shaft is a common and important machine element. It is a rotating member, in general,

has a circular cross-section and is used to transmit power. The shaft may be hollow or

solid. The shaft is supported on bearings and it rotates a set of gears or pulleys for the

purpose of power transmission. The shaft is generally acted upon by bending moment,

torsion and axial force. Design of shaft primarily involves in determining stresses at

critical point in the shaft that is arising due to aforementioned loading. Other two similar

forms of a shaft are axle and spindle. Axle is a non-rotating member used for supporting

rotating wheels etc. and do not transmit any torque. Spindle is simply defined as a short

shaft. However, design method remains the same for axle and spindle as that for a shaft.

Fig-17 Mechanical shaft for Exhaust system

This is the mechanical shaft which will consist all the major parts of the system. The

axial flow reaction turbine and backward curved fan and electrical generator will be

connected by a single shaft. It will be lighter in weight, strong enough to bear all the

loads like-shear force, torsional stress, and bending force. The material should be higher

in strength, tough, high melting temperature, corrosion resistant, high YTS (Yield tensile

strength) and low plasticity region. Mechanical shaft will face bending stress, axial force,

transverse force, torsional stress and shear force on different locations [8].

It will be made by AISI 1018, AISI 1020, Aluminum Alloy and High strength material

with light weight. The shaft diameter is also decided by maximum bending stress of the

27 | P a g e

shaft by SFD (Shear Force Diagram) and BMD (Bending Moment Diagram). The shaft

will be made by turning on CNC or Lath.

5.1.1 Shaft Designing Process

a) Standard sizes of Shafts [8]

Typical sizes of solid shaft that are available in the market are,

Up to 25 mm 0.5 mm increments

25 to 50 mm 1.0 mm increments

50 to 100 mm 2.0 mm increments

100 to 200 mm 5.0 mm increments

b) Material for Shafts

The ferrous, non-ferrous materials and nonmetals are used as shaft material depending on

the application. Some of the common ferrous materials used for shaft are discussed

below.

Hot-rolled plain carbon steel

These materials are least expensive. Since it is hot rolled, scaling is always present on the

surface and machining is required to make the surface smooth since it is cold drawn it has

got its inherent characteristics of smooth bright finish. Amount of machining therefore is

minimal. Better yield strength is also obtained. This is widely used for general purpose

transmission shaft.

Alloy steels

Alloy steel as one can understand is a mixture of various elements with the parent steel to

improve certain physical properties. To retain the total advantage of alloying materials

one requires heat treatment of the machine components after it has been manufactured.

Nickel, chromium and vanadium are some of the common alloying materials. However,

alloy steel is expensive. These materials are used for relatively severe service conditions.

When the situation demands great strength then alloy steels are used. They have fewer

28 | P a g e

tendencies to crack, warp or distort in heat treatment. Residual stresses are also less

compared to CS (Carbon Steel).

In certain cases the shaft needs to be wear resistant, and then more attention has to be

paid to make the surface of the shaft to be wear resistant [8].

The common types of surface hardening methods are

1. Hardening of surface

2. Case hardening and carburizing

3. Cyaniding and Nit riding

c) Design considerations for shaft

For the design of shaft following two methods are adopted

Design based on Strength

In this method, design is carried out so that stress at any location of the shaft should not

exceed the material yield stress. However, no consideration for shaft deflection and shaft

twist is included.

Design based on Stiffness

Basic idea of design in such case depends on the allowable deflection and twist of the shaft.

Basic stress equations:

Bending stress

M: Bending Moment at the point of interest

d0: Outer diameter of the shaft

K: ratio of the inner shaft to outer shaft diameter

(K=0 for solid shaft because solid shaft has zero diameter)

Axial Force

F: Axial force (tensile or compressive)

29 | P a g e

α: Column-action factor (= 1.0 for tensile load)

The term α has been introduced in the equation. This is known as column action factor.

What is a column action factor? This arises due the phenomenon of buckling of long

slender members which are acted upon by axial compressive loads.

Here, α is defined as,

Where:

n = 1.0 for hinged end

n = 2.25 for fixed end

n = 1.6 for ends partly restrained, as in bearing

K = least radius of gyration,

L = shaft length

ycσ = yield stress in compression

Stress due to torsion

T : Torque on the shaft

xyτ : Shear stress due to torsion

Combined Bending and Axial stress

Both bending and axial stresses are normal stresses, hence the net normal stress is given

by,

The net normal stress can be either positive or negative. Normally, shear stress due to

torsion is only considered in a shaft and shear stress due to load on the shaft is neglected.

30 | P a g e

Maximum shear stress theory

Design of the shaft mostly uses maximum shear stress theory. It states that a machine

member fails when the maximum shear stress at a point exceeds the maximum allowable

shear stress for the shaft material. Therefore,

Substituting the values of σx and τ

xyin the above equation, the final form is,

Therefore, the shaft diameter can be calculated in terms of external loads and material

properties. However, the above equation is further standardized for steel shafting in terms

of allowable design stress and load factors [8].

5.2 Bearings

Depending upon the design of a shaft or housing, the shaft may be influenced by an

unbalanced load or other factors which can then cause large fluctuations in bearing

efficiency. For this reason, it is necessary to pay attention to the following when

designing shaft and housing:

1) Bearing arrangement selection; most effective fixing method for bearing arrangement

2) Selection of shoulder height and fillet radius of housing and shaft.

3) Shape precision and dimensions of fitting; area run out tolerance of shoulder.

4) Machining precision and mounting error of housing and shaft suitable for allowable

alignment angle and inclination of bearing [9].

5.2.1 Fixing of bearings When fixing a bearing in position on a shaft or housing, there are many instances where

the interference fit alone is not enough to hold the bearing in place. Bearings must be

fixed in place by various methods so that they do not move axially when placed under

load.

Moreover, even bearings which are not subjected to axial loads (such as cylindrical roller

bearings, etc.), must be fixed in place axially because of the potential for ring

displacement due to shaft deflection by moment load which may cause damage [9].

31 | P a g e

Table No.-3 General Bearing Fixing Method

Table No.-4 Fixing methods for bearings with tapered bores

5.2.2 Bearing fitting dimensions

Abutment height and fillet radius The shaft and housing abutment height (h) should be larger than the bearings' maximum

allowable chamfer dimensions (rs max), and the abutment should be designed so that it

directly contacts the flat part of the bearing end face. The fillet radius (ra) must be

smaller than the bearing's minimum allowable chamfer dimension (rs min) so that it does

not interfere with bearing seating. Table5 lists abutment height (h) and fillet radius (ra).

For bearings to be applied to very large axial loads as well, shaft abutments (h) should be

higher than the values in the table [9].

32 | P a g e

Fig. 18 Dimensioning of Bearing

Table No.-5 Fillet Radius and abutment height

For spacer and ground undercut

In cases where a fillet radius (ra max) larger than the bearing chamfer dimension is

required to strengthen the shaft or to relieve stress concentration (Fig.19 a), or where the

shaft abutment height is too low to afford adequate contact surface with the bearing

33 | P a g e

(Fig. 19 b), spacers may be used effectively. Relief dimensions for ground shaft and

housing fitting surfaces are given in Table 6 [9].

(a) (b)

Fig-19 Bearing Mounting spacer

Table No.-6 Relief dimensions for ground shaft

Thrust bearings and fitting dimensions

For thrust bearings, it is necessary to make the raceway washer back face sufficiently

broad in relation to load and rigidity, and fitting dimensions from the dimension tables

should be adopted. (Figs. 14.2 and 14.3) For this reason, shaft and abutment heights will

34 | P a g e

be larger than for radial bearings. (Refer to dimension tables for all thrust bearing fitting

dimensions.)

Fig-20 Thrust bearings and fitting Fig-21 Roller bearing and Fitting

Shaft and housing accuracy

Table 7shows the accuracies for shaft and housing fitting surface dimensions and

configurations, as well as fitting surface roughness and abutment sureness for normal

operating conditions [10].

Table No.-7 Shaft and housing accuracy

5.3 Casing

The casing will hold all mechanism. It would be lighter in weight and high melting

temperature material so it can be stand with all conditions. Casing will be removable and

easy to access all the parts for changing the part and for maintenance it will be beneficial.

It will consist housing of bearings, axial shaft, electricity generator, turbine and fan blade

35 | P a g e

also. It will be in two parts, which will be fixed by screws. This will have housings for

bearings. Bearings will be fitted in outer casing. It will be in circular form like a conical

pipe. It will also consist two vertical stands to fix with engine exhaust system. These

vertical stand would be much stronger, tough and hard to resist the high air pressure.

Fig-22 Outer Casing design

5.3.1 Casing Design

The casing design will be high accuracy design, the design will consider the applying

forces, temperature, pressure and suitable material. It will be geometric and aerodynamic

design. It will should be lighter in weight and heavy in strength. The use material should

be friendly with machining process. The casing design will consist 3 loading points and

circular surface with shear force tension. The design will be checked by FEA analysis in

CAD software and then with a factor of safety the design will be finalized for the project

[10].

6. Electricity Generator

Electric Generator is a machine that produces electricity. Generators produce almost all

the electricity used by people. They furnish electric power that runs machines in

factories, provides lighting, and operates home appliances. Generators were once called

dynamos, a shortened form of the term dynamoelectric. A generator may be small enough

36 | P a g e

to hold in one hand. The midget generators used in some scientific instruments produce

only enough electricity to move a small pointer across a dial. Or a generator may be

bigger than a house. It can supply electric power for as many as 1 million homes.

The size of large generators is usually measured in kilowatts. One kilowatt equals 1,000

watts. A giant generator can produce more than 1 million kilowatts of electricity [11].

There are two main types of generators.

(1) Direct-current (DC) generators produce electric current that always flows in the

same direction.

(2) Alternating-current (AC) generators, or alternators, produce electric current that

reverses direction many times every second.

6.1 Electricity Generator Working

Basic Principles. A generator does not create energy. It changes mechanical energy into

electrical energy. Every generator must be driven by a turbine, a diesel engine, or some

other machine that produces mechanical energy. For example, the generator in an

automobile is driven by the same engine that runs the car.

Engineers often use the term prime mover for the mechanical device that drives a

generator. To obtain more electrical energy from a generator, the prime mover must

supply more mechanical energy. If the prime mover is a steam turbine, for example, more

steam must flow through the turbine in order to produce more electricity [11].

Generators produce electricity by means of a principle discovered independently by two

physicists in the early 1830's--Michael Faraday of England and Joseph Henry of the

United States. They found they could produce electricity in a coil of copper wire by

moving the coil near a magnet or by moving a magnet near the coil. This process is called

electromagnetic induction. The voltage, or electromotive force, of the electricity

produced is called an induced voltage or induced electromotive if the wire is part of a

closed circuit of wires, the induced voltage causes an electric current to flow through the

circuit

37 | P a g e

Fig-23 Configurations of Electricity generators

Parts of a Generator. A generator has two main parts: an armature and a field structure.

The armature contains coils of wire in which the electricity is leading to the device that

will use the electricity. The current produced in the loop of wire flows in and out of the

generator through the rings and brushes to the device [11].

How DC Generators Work.

The commutator rotates with the loop of wire just as the slip rings do with the rotor of an

AC generator. Each half of the commutator ring is called a commutator segment and is

insulated from the other half. Each end of the rotating loop of wire is connected to a

commutator segment. Two carbon brushes connected to the outside circuit rest against

the rotating commutator. One brush conducts the current out of the generator, and the

other brush feeds it in. The commutator is designed so that, no matter how the current in

the loop alternates, the commutator segment containing the outward-going current is

always against the "out" brush at the proper time. The armature in a large DC generator

has many coils of wire and commutator segments. Because of the commutator, engineers

have found it necessary to have the armature serve as the rotor and the field structure as

the stator. The type of generator used for a certain task depends on the amount of voltage

control required. For example, a DC generator used to charge a battery needs only simple

voltage control. It might be a shunt generator [11].

38 | P a g e

Fig-24 DC Generator

6.2 Specification of Used Electricity Generator

We will use 12 Volt DC generator. Which will be connected with shaft by chain

mechanism with the driving shaft. This DC motor will give maximum output on 200 rpm.

It the minimum rpm that we can achieve by the exhaust system on idling conditions. We

would get maximum output at minimum rpm condition or on vehicles idling condition.

The electricity generator will be small in size and lower in weight. It will be coated with

high temperature resistive material and fixed in a metal chamber to save form hot gasses.

We will use this electricity to charge the battery and other use in automobile vehicles. DC

generator will be very light in weight and very cheap in cost.

7. Flywheel

Flywheel stores the kinetic energy in form of motion. It gives a constant and smooth

power output or circular motion. It can be designed by equations derived from

conservation of energy principles are used in conjunction with design parameters and

constraints to yield an optimization diagram indicating the flywheel should be a disk with

diameter 0.15 m and thickness 0.013 m. Principles of static equilibrium are used in

parallel with the Distortion Energy Theory to show the shaft must be at least 0.108 m in

diameter to avoid both large deformations and failure. These results have a direct and

39 | P a g e

instant impact on both the design and progression of Pedal Pure’s concept; the feasibility

of their design is reinforced by this study and the results presented will assist them in

component purchasing and selection [12].

Fig-25 Automotive Flywheel

7.1 Flywheel Designing

Pedal Pure is designing human-powered water still. The current concept calls for a

rotating shaft to transfer power between the rear wheel of a bicycle and a generator. A

flywheel will be mounted to this shaft to minimize variations in shaft acceleration. The

purpose of this study is twofold; to determine the minimum shaft diameter needed to

withstand the proposed loading and also to optimize the flywheel geometry (see Figure

27) within given design constraints. The results of this study will have a direct and

immediate impact on Pedal Pure’s design. When selecting a shaft from a supplier, the

diameter recommended by this study will serve as the minimum allowable design

dimension; further, they should attempt to purchase a flywheel with dimensions as close to

those optimized by this study. The set-up to be analyzed is shown in Figure 26 [12].

Fig-26 Two dimensional representation of shaft with Flywheel

40 | P a g e

Fig-27 Flywheel Geometry

The methods used in this study are largely based on information presented in Chapter 11

of Fundamentals of Machine Elements. Two sections of this text provide step-by-step

problem solving approaches for shafts and flywheels used in configurations similar to

Pedal Pure’s design. Several assumptions are made in both the text and this report. Most

significantly, the mass of the shaft is neglected. While this simplification introduces some

error into the final value, the margin of this error is small and will be compensated for by

the built-in factor of safety. Secondly, the actual system has been idealized in several

ways; axial loading is neglected; it is assumed that the bearings and shaft are perfectly

aligned and concentric, and it is assumed that the flywheel is a perfect cylinder. These

assumptions have been introduced to simplify the model for analysis and introduce only

minor errors into the final value. The only limitation on information pertains to the

generation of the torque diagram, as it was very difficult to determine at which points

during the pedaling cycle energy is drawn from the flywheel. Several riders were

videotaped and polled in order to determine at which points the rider is unable to provide

power to the shaft (see Appendix for torque diagram.) [12].

The flywheel geometry must first be optimized and then the minimum required shaft

diameter can be found. In dimensioning the flywheel, both its diameter and composition

are considered design variable (see Table 1), but the group has already decided to

fabricate the flywheel from a cylindrical piece of medium carbon steel. Solving for the

flywheel geometry consists of applying conservation of energy principles to link the

design parameters and state variables.

41 | P a g e

Table No. 8Design Parameters and Variable for Flywheel Design

The designer can then select a diameter such that all constraints are met. As there are an

infinite number of diameters that satisfy the governing equations, the particular design

instantiation with the most merit must be selected. In this case the best flywheel is the

one with the least mass that does not exceed either constraint.

The first step in designing the shaft is to use static equilibrium to determine all

forces and moments acting on the shaft. From these forces, bending moment diagrams are

constructed and used to identify the maximum moment in the shaft. The Distortion

Energy Theory (DET) is then applied to determine the smallest diameter at which failure

will being to occur [12].

The following table identifies important parameters and variables associated with

designing the shaft. Determining the diameter with the most merit is simple; as Pedal

Pure does not want to over-design their shaft, the best shaft is the one with the smallest

diameter that will not fail or deform excessively. Thus, two constraints are imposed on

the shaft; it cannot fail and should not have excessive deformations. Diameters that

satisfy the DET will meet both criteria [12].

Table No. 9 Table 2: Design Parameters and Variables for Shaft Design

42 | P a g e

8. Summary

This project is an innovative project in which we are trying to using waste energy from

automotive engines in a constructive manners. We are generating electricity and

improving engine performance by this project. We have completed theory part and some

calculations of designing part. Now we has decided all the things related project and now

we will make calculations very soon and start the manufacturing process of parts. This

report consist the theoretical part and layout of project. All the major parts and its

working are also explained in this report with details.

43 | P a g e

References:-

[1] J. S. Jadhao, D. G. Thombare, Review on Exhaust Gas Heat Recovery for I.C. Engine,

ISO 9001:2008 Certified International Journal of Engineering and Innovative Technology

(IJEIT) Volume 2, Issue 12, June 2013.

[2] Andrew P. Freedman, ‘A Thermoelectric Generation Subsystem Model for Heat

Recovery Simulations’, pp 13-16, 24 ,31, 93- 101,M.S. Thesis, Rochester Institute of

Technology (2011)

[3] Chaung Yu, K.T. Chau, ‘Thermoelectric Automotive Waste Heat Energy Recovery

Using Maximum Power Point Tracking, Journal of Energy Conversion And Management

(2009)

[4] Jorge Vazquez, Miguel A. Sanz-bobi, Rafael Palacios, Anteneo Arenas, ‘State of the

Art of Thermoelectric Generators Based onHeat Recovered From The Exhaust Gases of

Automobiles’,UniversidadPontificiaComillas, Spain (2008)

[5] Francis Stabler , ‘Automotive Thermoelectric Generator Design Issues’, DOE

Thermoelectric Applications Workshop.

[6] C. Ramesh Kumar, AnkitSonthalia, Rahul Goel, ‘Experimental Study on Waste Heat

Recovery from An Internal Combustion Engine Using Thermoelectric Technology’

Center of Excellence for Automotive Research, VIT University, Vellore, India (2011)

[7] K. M. Saqr1, M. K. Mansour and M. N.Musa, ‘Thermal Design of Automobile

Exhaust Based Thermoelectric Generators: Objectives and Challenges’, International

Journal Of Automotive Technology (2007)

[8] V Ganesan, ‘Internal Combustion Engines’, pp 576, Third Edition, pub.-Tata

McGraw-hill (2009)

[9] R K Rajput, ‘Heat and Mass Transfer’, Third Edition, pub.-Tata McGraw-hill (2009)

[10] P K Nag, ‘Power Plant Engineering’, pp 851, 3rd Edition, pub. - Tata McGraw-hill

(2010)

[11] Wojciechowski,J. Merkisz , P. Fu, P. Lijewski, M.Schmidt,‘Study of Recovery of

Waste Heat From the Exhaust of Automotive Engine’ The 5th European Conference on

Thermoelectrics, Ukraine (2007)

[12] Gregory P. Meisner, ‘Materials and Generator Technology for Automotive Waste

Heat at GM.’ General Motors Global Research & Development, Thermoelectric

Applications Workshop (20S11)