EME Module 1 introduction to mechanical engg

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Anand Kulkarni, Assistant Professor, Mechanical Department, CiTech

Anand Kulkarni, Assistant Professor, Mechanical Department, CiTech 2
Mechanical engineering is one of the oldest and broadest engineering disciplines, and plays
a significant role in enhancing industrial safety, economic strength, societal quality of life
throughout the world.
In the previous century, were developed engineering achievements that have contributed to
the increase in life expectancy, improved health conditions, increased mobility thanks to the
development of the automobile and the airplane, increased productivity of labor as many of the
products made available to many people. In the future Mechanical engineering will develop
engineering solutions that foster a cleaner, healthier, safer and sustainable world.
Energy Sector: Mechanical engineers in the energy industry design and operate fossil fuel,
hydroelectric, conventional, nuclear, and cogeneration power plants. They are involved in all
aspects of the production and conversion of energy from one form to another. Mechanical
Engineering is directly related to the application and development of equipment to create and
transform any kind of energy and use it.

Manufacturing Sector: Here Mechanical
Engineer has responsible for all aspect of the
design, development, implementation, operation
and management of manufacturing system.
The job of manufacturing/production Engineer
involves the use of machine tools, materials and
human resources in the most effective way to
produce any goods.
Automobile Sector: The automotive industry relies heavily on the field of mechanical
engineering to improve safety, fuel consumption, and emissions control. Recent advancements
in mechanical engineering design, process optimizations enabled engines are quieter, faster,
and more fuel efficient. Also Currently, the areas where engineers are focused include
enhancing the transmissions, fuel injection systems, creating hybrid vehicles that can run on
battery as well as IC Engines.

Aerospace Sector: Aerospace engineering is the primary field of engineering concerned with
the development of aircraft and spacecraft. The most important role of the mechanical
engineer involves the design of engines, propellers, selection of materials, high precision
fabrication processes etc. Air conditioning systems also influences the efficiency of gas
turbines as well as the comfort of the personnel in the spacecraft.
Marine Sector: Marine engineering is the engineering of boats, ships, submarines, and any
other marine vessel. Marine engineering incorporates many aspects of mechanical engineering.
Such as design of shipboard propulsion systems, steering, anchoring, cargo handling, heating,
ventilation, air conditioning etc.

The Mechanical engineering profession makes important contributions to the economy, both
from the direct addition to economic output from the work they do, and the contribution of the
sectors in which they work.
One can also consider the long run return to the economy of improvements in physical
infrastructure, in which engineers have played a vital role, and the contributions engineers
make to the knowledge economy and to sustainability.
Impact of Energy Sector on GDP: Economic growth is the dominant goal of any country’s
economic policy. The measure of economic growth - GDP reflects the increase in the value of
manufactured goods and services in a given country in a specific period GDP is commonly
seen as an indicator of economic activity.
Currently, manufacturing accounts for about 15 per cent of the country's GDP. Keeping the
economic growth, urbanization and industrial activity all four major energy-consuming sectors
industry, household, transport, and agriculture will see a rise in demand.

Impact of Manufacturing Sector on GDP: Currently, manufacturing accounts for about 15
per cent of the country's GDP. The Indian Manufacturing sector currently contributes 16-17%
to GDP and gives employment to around 12%. While a number of factors like robust domestic
demand, a growing middle class, a young population and a high return on investment, makes
India a credible investment destination and presents an attractive opportunity to manufacturers.
Several mobile phone, luxury and automobile brands, among others, have set up or are looking
to establish their manufacturing bases in the country.
Impact of Automobile Sector on GDP: The contribution of the automobile sector to the
overall GDP of India stands at 7.1 per cent and 49 per cent of the manufacturing GDP.
Across the world, automobile industry is a spark for regional development. Industrial
clusters form as original equipment manufacturer (OEM) plants are surrounded by
component manufacturing facilities, including steel plants, glass manufacturers, car
dealerships, aftermarket shops, and transportation service providers. These clusters lead to
new municipalities with solid road infrastructures, railway and freight connectivity, and new
housing developments. R&D investment by automakers is driven by consumer demands for
more product variety, better performance, improved safety, higher emission standards, and
lower costs.

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Phase Change of Water on T-h Diagram
Sub Cooled Liquid
1
Saturated Liquid
2
Wet Steam
3
Dry Steam
4
Super Heated Steam
5
Tsat = 100 0C
Sensible Heat
Latent Heat
Super Heat
0 0C

Consider 1 kg water in friction free cylinder. Let piston applies a constant pressure on water as shown in
figure. Assume that this experiment is carried out at constant atmospheric pressure. The water is heated
from the other end of the cylinder.
State 1 (Subcooled Liquid): Consider liquid Water is heated from say 0 0C temperature, at this state the
water is assumed in liquid state and below the boiling (Saturation) temperature. Hence it is called as
subcooled liquid state. Water remains in subcooled state till it reaches the saturation temperature. At
subcooled state, upon adding heat, there is rise in temperature of water.
State 2 (Saturated Liquid): When water temperature reaches to saturation temperature , 100 0C, the water
starts boiling. The further addition of heat will no rise the temperature of the water. From the state 2, the
liquid water starts converting to vapour state. .At this point dryness fraction will be x = 0.
State 3 (Wet Steam): At the state 3, water is in two state i.e liquid and vapour state. Since the vapour is in
contact with water, steam is called as wet steam. Further addition of heat there is no rise in saturation
temperature and it remains in wet steam till all liquid is converted into vapour state. At the wet state
condition, the dryness fraction (x) varies from 0 to 1.
State 4 (Dry Steam): When all liquid water converted into vapour state, vapour becomes dry steam. At
this point dryness fraction will be x = 1. Further addition of heat will increase the temperature of the steam.
State 5 (Superheated Steam): On further addition of heat, the temperature of steam starts increasing and
the steam is super heated steam.

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 Enthalpy or Sensible or Total Heat of Water[hf] : Amount of heat required to convert 1 kg of water
from ice point to boiling point at constant pressure. It is represented by, hf.
hf= 4.18[Tsat-Tice]…….kJ/Kg.
 Latent heat of Vaporization[hfg]: Amount of heat required to convert 1 kg of water to completely
steam. It is represented by, hfg.
For water, hfg= 2260 kJ/Kg.
 Enthalpy of wet steam [hw]: Amount of heat required to convert 1 kg of water from ice point to given
dryness fraction. It is represented by, hw.
hw= hf+x hfg…….kJ/Kg.
 Enthalpy of dry steam [hg]: Amount of heat required to convert 1 kg of water from ice point to dry
steam. It is represented by, hg.
hg= hf+hfg …….kJ/Kg.
 Enthalpy of super heated steam[hsup]: Amount of heat required to convert 1 kg of water from ice
point to given degree of superheat of steam. It is represented by, hsup.
hsup= hg + Cps[Tsup-Tsat]…….kJ/Kg
Where, Cps = Specific Heat of Steam = 2.1 kJ/KgK

 Degree of Superheat: The difference between super heated temperature and the saturation temperature
is called degrees of saturation.
[Tsup-Tsat] = Degree of Superheat.
 Dryness Fraction(x) or Quality of steam[x]: It is the ration of Mass of dry steam to mass of wet
steam.
𝑥 =
𝑀𝑎𝑠𝑠 𝑜𝑓 𝐷𝑟𝑦 𝑆𝑡𝑒𝑎𝑚
𝑀𝑎𝑠𝑠 𝑜𝑓 𝑊𝑒𝑡 𝑆𝑡𝑒𝑎𝑚
=
𝑚𝑔
𝑚𝑔+𝑚𝑓
 Super Cooled Liquid: Liquid that exist below its boiling temperature.
 Saturated liquid: It is state of a substance at which liquid starts vaporizing on heating at constant
pressure.
 Saturated Vapour: It is state of a substance at which liquid starts condensing on cooling at constant
pressure.
 Saturation Temperature: The temperature at which a liquid starts boiling at the given pressure is
called as saturation temperature.
Ex: Tsat = 100 0C at atmospheric pressure (1.01325 bar)

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1. Sugar Industries: In the sugar factory, steam is mainly used to generate electricity,
concentrate sugar juice and dry sugar.
2. Diary Industries: The milk processing plants utilize steam for processing and pasteurizing
raw milk and dairy products under heat treatment. It leads to the process and production of
various dairy products such as milk powder, yogurt, cheese, condensed milk, skimmed
milk, butter, ghee, and cream.
3. Paper Industries: The paper industries will use steam to produce pulp, where, the wood
chips are cooked with steam with a chemical solution that is eventually dissolved and
formed into a pulp. Further, steam is used to produce electric power for other industrial
processes.
4. Food Industries: Direct heat or heat from the hot water is an essential factor of food
processing industry. Inside the food industry, steam is used for cooking, drying, and
warming, and for general utilize-cleaning. Steam is also used to eliminate microbiological
risk in food. Ex: Hot Water Generation for Sanitation, Steam for Cooking, Steam for
Drying Food etc.

5. Power Generation: A steam power plant consists of a
boiler, steam is passed into turbine and generator,
pump and other auxiliaries. The boiler generates
steam at high pressure and high temperature. The
steam turbine converts the heat energy of steam into
mechanical energy. The generator then converts the
mechanical energy into electric power. Tus steam act
as a working fluid to convert heat energy into
mechanical energy.
6. Atomization: Steam atomizing helps in breaking up
fuel oil particles into tiny droplets, facilitating easy
spread of oil inside the furnace, and maximizing
combustion. The result is a well spread and intense
flame. Without the injection of steam into the burner,
the physical state of fuel oil will remain in a liquid
form.

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Figure: Schematic Representation of Hydro Power Plant

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1. Reservoir: It stores large amount of water behind the dam. The energy stored in reservoir is
potential energy. The height of the water stored in reservoir will determine the potential energy
stored in water.
2. Surge Tank: A surge tank is a small reservoir or tank which is open at the top. It is fitted between
the reservoir and the turbine inlet. When there is sudden reduction in load on the turbine, the
governor closes the gates of the turbine to reduce the water flow. This causes pressure to increase
abnormally in the penstock. This is prevented by using a surge tank, in which the water level rises
to reduce the pressure. On the other hand, the surge tank provides excess water needed when the
gates are suddenly opened to meet the increased load demand.
3. Penstock: A penstock is a huge steel pipe which carries water from the reservoir to the turbine.
Potential energy of the water is converted into kinetic energy as it flows down through the penstock
due to gravity.
4. Water Turbine: It converts high kinetic energy into mechanical energy once the water flows over
the turbine blades.
5. Generator: The generator shaft is coupled to turbine shaft. In generator, mechanical energy is
converted into electrical energy. This electric energy is further transmitted to grids.
6. Draft Tube: It is pipe through which water discharged into river.

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Hydroelectric power plant (Hydel plant) utilizes the potential energy of water stored in a dam
built across the river. The potential energy of the stored water is converted into kinetic energy
by first passing it through the penstock pipe. The kinetic energy of the water is then converted
into mechanical energy in a water turbine. The turbine is coupled to the electric generator. The
mechanical energy available at the shaft of the turbine is converted into electrical energy by
means of the generator.
• No fuel is required as potential energy is stored
water is used for electricity generation
• Neat and clean source of energy
• Very small running charges - as water is
available free of cost
• Comparatively less maintenance is required
and has longer life
• Serves other purposes too, such as irrigation
• High construction cost is required due to
construction of dam.
• long transmission line is required to
transmit this hydroelectric power.
• It doesn't supply constant
hydroelectricity due to the availability of
water.

(Vapour)
(Liquid + Vapour)
(Liquid)
(Liquid)
Figure: Schematic Representation of Thermal Power Plant

• Boiler: Boiler is a heat exchanger. Here heat from the hot flue gas is transferred to water. After
absorbing heat, liquid water is converted into vapour state. At the outlet of the boiler, steam at
very high pressure and in super heated condition. This steam is taken to turbine inlet nozzle.
Flue gases are generated after the burning the coal. Since the coal is fossil fuel, it generates
large emissions NOx, SOx, CO and CO2.
• Steam Turbine: Turbine is work producing device. It converts kinetic energy of the steam
into mechanical energy when steam is made to expand on the turbine blades. The expanded
steam is in binary state of vapour and liquid. This expanded steam enters into condenser.
• Generator: Generator is a electric device, which converts mechanical energy into electric
energy. Thus produced electric energy is transmitted to electric grids.
• Condenser: Condenser is a heat exchanger. Here seat from turbine enters into condenser tubes
and loses heat to the cold water. After losing heat, the steam converted into liquid state.
• Pump: Pump is a work absorbing device. The liquid water is fed back to boiler with help of
feed water pump. It will regulate the flow of water in boiler so as to generated the steam at
desired quantity and pressure levels.

Thermal power plant utilizes the heat energy stored in coal to convert liquid water into super
heated steam in boiler. In the boiler, the steam produced at very high pressure. This high
pressure is converted into kinetic energy with the nozzle. This expanded steam is then passed
over the steam turbine blades. Where, high kinetic energy of steam is converted into
mechanical energy. Thus produced mechanical energy is converted into electrical energy with
help of generator. This electric energy transmitted to electric grids.
The steam expanded in turbine is further cooled in condenser. After condensation vapor is
converted into liquid water. This water is pumped back to boiler with the help of feed water
pump.

• The coal (fuel) is cheaply available.
• It requires less floor area compared to hydro power plant
• The energy content in fuel is high. Hence it is used for large power generation projects.
• Less initial cost require as compared to other generating stations.
• Thermal plants are able to respond to the load demand more effectively and support the
performance of the electrical grid.
• Thermal power plant creates pollution due to large amount of smoke and fumes because of
coal combustion.
• A large amount of water source require for condensation of steam.
• Running cost high compared to hydro-power plant.
• Handling of coal and disposal of ash is quite difficult and requires a large area.
• Starting time is quite longer than other power plants.
• Efficiency is less around 30-35 %

Figure: Schematic Representation of Nuclear Power Plant
Coolant
(Primary Fluid)
(Secondary Fluid)

0
1
𝑛 + 92
235
𝑈 56
141
𝐵𝑎 + 36
92
𝐾𝑟 + 3 0
1
𝑛 + 𝐸𝑛𝑒𝑟𝑔𝑦
In the nucleus of each atom of uranium-235 (U-235) are 92 protons and 143 neutrons, for
a total of 235. The arrangement of particles within uranium-235 is unstable and the nucleus
can disintegrate if it is bombarded by an outside source. When a U-235 nucleus absorbs an
extra neutron, it quickly breaks into two parts i.e. Barium and Krypton along with releasing
enormous amount of heat energy. Each time a U-235 nucleus splits, it releases three
neutrons. This leads to chain reaction.
The success of fission reaction also the function of kinetic energy of the neutron. To
control the chain reaction, moderators are used to reduce the kinetic energy of neutron
The heat released after the fission reaction is used in nuclear power plant to produce
electric energy.

• Nuclear Reactor: In nuclear reactor the fission reaction is initiated by bombarding heavy
nucleolus of the fuel (Uranium) with the neutron. This fission reaction generates enormous
amount of heat energy. This heat is absorbed by the fluid and exchanges heat to secondary
fluid in heat exchangers. The reactor has following components
• Moderator: It reduces the kinetic energy of the neutron to control the chain reaction.
Generally graphite is used as moderator.
• Thermal Shield: This concrete structure avoids leakage of radiation to the outer
atmosphere.
• Coolant: Coolant absorbs heat from the nuclear reactor that keeps the reactor cooled.
This heat further exchanged to secondary liquid in heat exchanger.
• Heat Exchanger(Boiler): It is a heat exchanger, where coolant from nuclear reactor will
transfer heat to water. After absorbing heat, water converts into super heated steam.
• Steam Turbine: Turbine is work producing device. It converts kinetic energy of the steam
into mechanical energy when steam is made to expand on the turbine blades. The expanded
steam is in binary state of vapour and liquid. This expanded steam enters into condenser.

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• Generator: Generator is a electric device, which converts mechanical energy into electric energy.
Thus produced electric energy is transmitted to electric grids.
• Condenser: Condenser is a heat exchanger. Here steam from turbine enters into condenser tubes and
loses heat to the cold water. After losing heat, the steam converted into liquid state.
• Pump: Pump is a work absorbing device. The liquid water is fed back to boiler with help of feed
water pump. It will regulate the flow of water in boiler so as to generated the steam at desired quantity
and pressure levels.
The nuclear power plant utilizes the heat energy generated during the fission reaction to convert liquid
water into super heated steam in heat exchanger. During the fission reaction enormous heat energy is
generated. This heat is absorbed by a coolant while passing through the thermal shield. This heat is
further transmitted secondary liquid (water). After absorbing heat liquid water becomes super heated
steam at very high pressure. This high pressure is converted into kinetic energy with the nozzle. This
expanded steam is then passed over the steam turbine blades. Where, high kinetic energy of steam is
converted into mechanical energy. Thus produced mechanical energy is converted into electrical energy
with help of generator. This electric energy transmitted to electric grids.
The steam expanded in turbine is further cooled in condenser. After condensation vapor is converted
into liquid water. This water is pumped back to boiler with the help of feed water pump.

• Nuclear Power Plant requires less space as compared to other Power plants.
• Well suited for large scale power generation.
• It has very high energy density compared all other power plants.
• Less fuel consumption and no fuel handling compared to thermal power plants.
• Increased reliability of operation.
• Compact and simple in maintenance.
• Nuclear Power Plant has a High initial cost.
• The danger of radioactivity hazards is always persisting.
• The disposal of fission products is a big problem.
• The maintenance cost is always higher.
• Working condition is always harmful to the health of the workers.

Figure: Schematic Representation of Solar Power Plant

• Solar Collector: A solar collector is a heat exchanger, where it transmits the heat from sun
radiation to water. After absorption of heat, water density reduces and high density cold water
pushes the hot water away from the collector. The
• Heat Exchanger (Butane Boiler): It is a heat exchanger, where hot water from solar collector
will transfer heat to butane. After absorbing heat, butane converts into super heated vapour.
Butane is selected as working fluid as it boils at low temperature.
• Turbine: Turbine is work producing device. It converts kinetic energy of the butane vapour into
mechanical energy when vapour is made to expand on the turbine blades. The expanded vapour
is in binary state of vapour and liquid. This expanded steam enters into condenser.
• Generator: Generator is a electric device, which converts mechanical energy into electric
energy. Thus produced electric energy is transmitted to electric grids.
• Condenser: Condenser is a heat exchanger. Here vapour from turbine enters into condenser
tubes and loses heat to the cold water. After losing heat, the steam converted into liquid state.
• Pump: Pump is a work absorbing device. The liquid butane is fed back to boiler with help of
feed pump. It will regulate the flow of butane in heat exchanger so as to generated the vapour at
desired quantity and pressure levels.

The solar power plant utilizes the heat energy from the solar radiations to heat liquid water in solar
collector. This water, after absorbing heat, enter into heat exchanger. In heat exchanger hot water
transmits heat to butane in liquid state. After absorbing heat, the liquid butane turns into vapour at high
pressure. As the temperature of water will be as low as upto 80 0C, it need a working fluid that boils
at low temperature like butane.
This high pressure vapour is converted into kinetic energy with the help of nozzle. This expanded
steam is then passed over the turbine blades. Where, high kinetic energy of steam is converted into
mechanical energy. Thus, produced mechanical energy is converted into electrical energy with help of
generator. This electric energy transmitted to electric grids.
The vapour expanded in turbine is further cooled in condenser. After condensation vapor is converted
into liquid butane. This butane is pumped back to heat exchanger with the help of feed pump.

• Endless amounts of energy, free of cost.
• Modern systems work efficiently even in winter
• Solar power is pollution-free and causes no greenhouse gases to be emitted after
installation
• Reduced dependence on import of foreign oil and fossil fuels like coal based plant etc.
• Plant can be installed at remote locations. Hence, power transmission losses are low.
• Cost of power generation is high.
• Needs thermal power storage system for uninterrupted working during when sun is
unavailable.
• Needs very large solar collector area for installation.
• Cannot supply continuous electric power.
• Only suitable where favorable sun-shine conditions are available.
• Low thermal efficiency.

Figure: Horizontal Axis Wind Turbine

• Turbine Blades: It is propellers with two, three or five blades mounted on the horizontal
shaft (this gives higher output than when they are mounted on the vertical shaft) and made
of a lightweight material such as carbon fiber, fiberglass or wood, that is strong enough to
resist wind forces. It is built with aero foil structure due to which kinetic energy of the wind
is converted into rotary motion of the turbine shaft.
• Gear Box: A Mechanical gearbox is used to increase the rotational speed of the generator.
• Generator: An Electrical generator is used to produce the electrical power which is
coupled on gear shaft.
• Support Structure: It supports the rotors, gearbox, generator and axillary equipment.

The wind power plant utilizes the kinetic energy from the wind to mechanical energy in
turn to produce electrical energy. Wind energy is created when the sun heats the earth
atmosphere unevenly causing thermosiphon effect. This thermosiphon effect is the cause for
formation of the wind. Hence, Wind energy, which is actually a secondary component of solar
energy
When the wind flows over the turbine blade, due to its aero foil shape, the kinetic energy
of the wind is converted into rotary motion of the shaft. These blades are connected to a hub.
Hub is further connected to gear box. Generally, the speed of the rotor is very low. This isn’t
enough to produce the high electric power. To increase the speed of the rotor, a gear box is
employed.
This high-speed shaft connects to an electrical generator that converts the mechanical
energy from the rotation of the blades into electrical energy.
Spinning between 11 and 20 times per minute, each turbine can generate a maximum 1.5
megawatts of electricity enough to power, on average, more than 500 residential homes.

• Air as a fuel is free and inexhaustible.
• It is clean source of energy and does note pollute the environment.
• The cost of electricity is too low and wind turbine could be used over more than 20 years
• It’s cheap as only the installation and maintenance cost is required.
• Wind generation can be done in remote areas and on any scale from small personal and
domestic use to large full size wind farms,
• It takes a lot of research and effort to decide the location where wind power plant has to
be installed, due to fluctuating pattern of wind.
• They are the greatest disadvantage to local bird population as they die due to collision
with blades.
• Noise pollution is the one of the major disadvantage.
• Wind power plant is only useful to the countries with coastal or hilly areas.

Figure: Tidal Power Plant

• Dam: The function of the dam is to form a barrier between the sea and the basin.
• Sluice Gates: are used either to fill the basin during high tide or empty the basin during the
low tide. Each time, water passes through the barrage, the turbine spins and electricity is
generated.
• Power House: Power house is situated at the mouth of basin. The hydraulic turbine in the
power house only operates during the discharge of water.
Principle: Tide is periodic rise and fall of water level of the sea. Tides occur due to the
attraction of sea water by the moon. Tides contain large amount of potential energy. This
potential energy is stored in water, this water is made to flow over the turbine blades.
Turbine is further connected to generator to produce electricity. When the water is above
the mean sea level, it is called high tide. When the water level is below the mean level it is
called low tide.

High Tide: During high tide period, The height of tide is above that of basin, water flows from
the sea into the basin through the barrage. This barrage is fitted with water turbine. When
water passes through the barrage, potential energy of the sea water is converted onto kinetic
energy od the water. When water flows over the turbine blades, kinetic energy is converted
into mechanical energy. Further, this turbine shaft is coupled to generator and it produces the
electric energy.
Low Tide: During low tide period, The height of basin is above that of sea, water flows from
the basin into the sea through the barrage in revers direction. During reverse flow also, water
flows over the turbine. Further, this turbine shaft is coupled to generator and it produces the
electric energy.
The generation of power stops only when the sea level and the tidal basin level are equal.

• It is free from pollution as it does not use any fuel.
• It is superior to hydro-power plant as it is totally independent of rain.
• It improves the possibility of fish farming in the tidal basins and it can provide recreation
to visitors and holiday makers.
• Tidal power plants can be developed only if natural sites are available on the bay.
• As the sites are available on the bays which are always far away from load centers, the
power generated has to be transmitted to long distances. This increases the transmission
cost and transmission losses.
• The supply of power is not continuous as it depends upon the timing of tides.
• Utilization of tidal energy on small scale is not economical.

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A water turbine is a hydraulic prime
mover that converts the kinetic
energy of water into mechanical
energy in the form of rotation of
shaft.
The mechanical energy in turn is
converted into electrical energy by
means of an electric generator.
Hydraulic Turbines
Anand Kulkarni, Assistant Professor, Mechanical Department,
CiTech
42

Classification of Hydraulic Turbine
1. According to type of energy at the turbine inlet
a. Impulse Turbine
b. Reaction Turbine.
2. According to direction of water flow inside
turbine runner
a. Tangential Flow
b. Radial Flow Turbine
c. Axial Flow Turbine
3. According to discharge (Quantity) of water
a. High Discharge Turbine
b. Medium Discharge Turbine
c. Low Discharge Turbine
4. According to Head (Height) of water
a. High Head Turbine
b. Medium Head Turbine
c. Low Head Turbine
5. According to Fluid used in turbine
a. Water (Hydraulic) Turbine
b. Steam Turbine
c. Gas Turbine
d. Wind Turbine
CiTech
43

Classification of Hydraulic Turbine
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1. According to type of energy at the turbine inlet
a. Impulse Turbine: A turbine that is driven by high velocity
jets of water or steam from a nozzle directed on to vanes
or buckets attached to a wheel. The resulting impulse
force rotates the turbine shaft in the direction of fluid
flow. Ex:- Pelton Turbine.
b. Reaction Turbine: A reaction turbine that rotates, due to
the reaction force generated by of the high velocity fluid
leaving the nozzles, opposite direction to that of the
fluid flow. Ex: Francis and Kaplan Turbine.
CiTech

45
Continued……
2) According to direction of water flow inside turbine runner
a. Tangential Flow: The water strikes buckets (Blades) in the tangential direction to the path of rotation.
Ex:- Pelton Wheel
b. Mixed Flow Turbine: The water enters radial direction through the runner and leaves turbine axially.
Ex:- Francis Turbine.
c. Axial Flow Turbine:- The water enters axially to the runner and leaves the turbine axially.
Figure: Tangential Flow Figure: Mixed Flow Figure: Axial Flow

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Continued……
Source: https://www.open.edu/openlearn/ocw/mod/oucontent/view.php?id=73762&extra=thumbnailfigure_idm45676359520256
3. According to Head (Height) of water
a. High Head Turbine: Turbine works with very high head i.e. more than 300 meters.
Ex:- Pelton Turbine
b. Medium Head Turbine: Turbine works with between 30 m to 300m of water head.
Ex:- Francis Turbine
c. Low Head Turbine: Turbine works with very low head less than 30 meters.
Ex:- Kaplan Turbine

Feature: Pelton turbine is a complete impulse, tangential flow, high head and low discharge water
turbine.
Pelton Turbine
CiTech
47
Figure: Pelton Turbine

It is a complete impulse, tangential flow, high head and low discharge water
turbine.
Construction:
Casing: The Pelton wheel casing prevents the splashing of water and it will provide a discharge of
water from the nozzle to the tailrace.
Nozzle: Nozzle converts high potential energy (Head) to high velocity water before input to
turbine.
Spear: Spear will control the water flow and it moves insides the nozzle and provides smooth
flow so there can be very less energy loss. When spear is moves inside, the flow rate of water will
reduce and vice versa.
Runner or Rotor: Runner is a rotating element that rotates in the turbine. at the periphery of the
runner equally spaced buckets. When the high kinetic energy water jet hits the buckets it gives
impulsive force on the buckets and setup the rotor to rotate in the direction of fluid flow.
Penstock: These are the pipelines from high source water is transferred to the actual power
station. Anand Kulkarni, Assistant Professor, Mechanical Department,
CiTech
48

Working: The water from high head source like dam is carried to the penstock pipes to the
nozzle. The nozzle is provided which converts the Potential Energy of high head water into a
high velocity water jet (K.E.). The high velocity water jet coming out from the nozzle
impinges on the buckets attached around the periphery of the wheel mounted on a shaft.
In order to control the quantity of water striking the buckets a spear is used. When
spear is moves inside, the flow rate of water will reduce and vice versa. The high velocity
water jet coming out from the nozzle create impulsive force on the buckets attached
around the periphery of the wheel mounted on a shaft. After imparting impulse on the buckets,
water is discharged out of turbine through tail race channel placed at the bottom of the rotor.
The impact of water on the surface of the buckets produces a force which causes
the wheel to rotate by supplying a torque (or) mechanical power on the shaft. This shaft is
coupled to the generator to produce electricity.
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Advantages and limitations of Pelton Turbine
Advantages:
1) Simple in construction and easy maintenance.
2) To drive more power multiple jets (2 to 6) Pelton wheel may be used.
3) Since, it is high head and low discharge turbine, it can be used when water
availability is less.
Disadvantages:
1) Since all energy is utilized in only one stage, hence, balancing at very high
speed is a challenge.
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Features: Francis turbine is a reaction, mixed flow, medium head and medium discharge turbine.
Francis Turbine
51
Figure: Francis Turbine

It is a reaction, mixed flow, medium head and medium discharge water turbine.
Construction:
Spiral Casing: It has uniformly decreasing cross section area, along the circumference. Its
decreasing cross-section area makes sure that we have a uniform velocity of the water striking the
runner blades.
Guiding Blades: Guide vanes are installed in the spiral casing, these blades will guide the water
into the rotor.
Runner blades: These blades are attached to the rotor. Water at high velocity enters the rotor
radially hits the blades and leave the blades axially giving reaction force to the rotor. Here, rotor is
rotated due to the reaction force, hence, it is called as reaction turbine. Note here that water enters
the rotor radially and leaves axially, hence, it can also be called as mixed flow turbine..
Draft Tube: Draft tube connects the runner exit to the tail race. Its function is to discharge water
from the rotor. Its cross-section area increases along its length, as the water coming out of runner
blades is at considerably low pressure, so its pressure increased water is discharged to towards tail
race.
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Working of Francis Turbine
Water will enter at the inlet with high pressure. As water enters the spiral casing it starts flowing
through guide vanes into the runner blades. Guide vanes guides the flow of water to strike the
runner blades to produce maximum power output. These guide vanes can change their angle to
increase or decrease the flow rate of water into turbine. Water enters the rotor radially inward
and leave the rotor axially form the center (Not shown in diagram). During this change in
direction, high velocity water imparts reaction force to the rotor, generating torque on the
rotor. This constitutes the rotation of rotor.
Water coming out after striking the runner blades, is at a really low pressure, so it is passed
through a draft tube with uniformly increasing cross-section area to recover its pressure as it
reaches the tail race.
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Working of Francis Turbine
Advantages:
1) No head loss occurs even at low discharge of water.
2) It operates at more range of discharge of water.
Disadvantages:
1) Cavitation is the major concern at very high speed.
2) Eddy losses are more due to change in the direction of flow.
3) Since the spiral casing is grounded, runner is not easily accessible. Hence
dismantling is difficult.
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Kaplan Turbine
Kaplan turbine is a reaction,
axial flow, low head and high
discharge turbine.
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Figure: Kaplan Turbine

It is a reaction, mixed flow, medium head and medium discharge water turbine.
Construction:
Spiral Casing: It has uniformly decreasing cross section area, along the circumference. Its
decreasing cross-section area makes sure that we have a uniform velocity of the water striking the
runner blades.
Guiding Blades: Guide vanes are installed in the spiral casing, these blades will guide the water
into the rotor.
Runner blades: These blades are attached to the rotor. Water at high velocity enters the rotor
radially hits the blades and leave the blades axially giving reaction force to the rotor. Here, rotor is
rotated due to the reaction force, hence, it is called as reaction turbine. Note here that water enters
the rotor radially and leaves axially, hence, it can also be called as mixed flow turbine..
Draft Tube: Draft tube connects the runner exit to the tail race. Its function is to discharge water
from the rotor. Its cross-section area increases along its length, as the water coming out of runner
blades is at considerably low pressure, so its pressure increased water is discharged to towards tail
race.
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Working of Kaplan Turbine
Water will enter at the inlet with high pressure. As water enters the spiral casing it starts flowing
through guide vanes into the runner blades. Guide vanes guides the flow of water to strike the
runner blades to produce maximum power output. These guide vanes can change their angle to
increase or decrease the flow rate of water into turbine. Water enters the rotor axially (parallel
to the axis of shaft) and leave the rotor axially form the center . During this axial flow, high
velocity water imparts reaction force to the rotor, generating torque on the rotor. This
constitutes the rotation of rotor.
Water coming out after striking the runner blades, is at a really low pressure, so it is passed
through a draft tube with uniformly increasing cross-section area to recover its pressure as it
reaches the tail race.
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Working of Kaplan Turbine
Advantages:
1) Simple in construction and requires less space.
2) Eddy losses are almost eliminated due to axial entry and axial exit of water.
Disadvantages:
1) Cavitation is likely to occur due to high velocity flow of water.
2) It requires higher discharge of water.
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A hydraulic pump is a device that converts
mechanical power into hydraulic energy.
OR
A hydraulic pump is a device that transfers
energy to raise liquid from a lower level to
a higher level.
Hydraulic Pumps
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www.cambridge.edu.in
Department of Mechanical Engineering
Centrifugal Pumps
Reciprocating pump is a non-positive displacement pump. It is often used where relatively high
quantity of water (discharge) is to be handled and the delivery pressure is small. 60
Figure: Centrifugal Turbine

Construction of Centrifugal Pumps
 Impellor: It is the rotating part of the pump. The impeller is mounted on a shaft and the shaft of
impeller is again connected with the shaft of an electric motor. It is rotated by the motor and
consists of series of backward curved blades.
 Volute Casing: It is a spiral type of casing in which the area of flow increases gradually. The
increase in area of flow decreases the velocity and increases the pressure of the liquid that
flows through the casing.
 Suction Pipe: A pipe whose one end is connected with the inlet of the impeller and the other
end is dipped into the sump of water is called suction pipe. The suction pipe consists of a foot
valve and strainer at its lower end.
 Delivery Pipe: It is a pipe whose one end is connected to the outlet of the pump and other end
is connected to the required height where water is to be delivered.
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www.cambridge.edu.in
Working of Centrifugal Pumps
 When the electric motor starts rotating, it also rotates the impeller. The rotation of the
impeller creates suction (vacuum) at the suction pipe. Due to suction created the water from
the sump starts coming to the casing through the center of the impeller.
 From the center of the impeller, due to the centrifugal force acting on the water, the water
starts moving radially outward and towards the outer of casing.
 Since the impeller is rotating at high velocity it also rotates the water around it in the
casing. The area of the casing increasing gradually in the direction of rotation, so the
velocity of the water keeps on decreasing and the pressure increases, at the outlet of the
pump, the pressure is maximum.
 Now form the outlet of the pump, the water goes to its desired location through delivery
pipe.
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Cavitation and Priming
 Cavitation is the formation of bubbles
or cavities in liquid, developed in areas
of relatively low pressure around an
impeller. The imploding or collapsing of
these bubbles trigger intense
shockwaves inside the pump, causing
significant damage to the impeller
and/or the pump housing.
Fig:- Some images of damage caused by cavitation,
Courtesy:- https://blog.craneengineering.net/
 If left untreated, pump cavitation can cause Failure of pump housing, destruction of
impeller and more power consumption.
 Priming is the operation in which the suction pipe, casing of the pump and the portion of
the delivery pipe up to the delivery valve are completely filled with the liquid so that all
the air(gas or vapour) from the pump is driven out and no air pocket is left.
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EME Module 1 introduction to mechanical engg

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