GE2152 BCM - BCAM QUESTION BANKS BASIC CIVIL AND MECHANICAL ENGINEERING|, QUESTION BANKS

anna university question banks for second semester, anna university second semester notes and question banks, GE2152 BASIC CIVIL AND MECHANICAL ENGINEERING QUESTION BANKS, QUESTION BANKS, 
B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2009 2010 2011

Second Semester

Electronics and Communication Engineering

GE 2152 — BASIC CIVIL AND MECHANICAL ENGINEERING(BCAM) or Bcm

(Common to Biomedical Engineering, Electrical and Electronics Engineering,

Electronics and Instrumentation Engineering, Information Technology, Computer

Science and Engineering and Instrumentation and Control Engineering)

(Regulation 2008)

Time : Three hours Maximum : 100 Marks

Answer ALL Questions

PART A — (10 × 2 = 20 Marks)


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UNIT III – Power Plant Engineering, Pumps and
Turbines.
1. Define power plant.
Powerlant is an industrial system composed of machinery ,equipment and
structures desingned to convert various energy resources into electricity on a large
scale.power plant is also called as power station or power house.
2. What are the different types of power plants
Depending on the type of energy source the power plants
areclassified as
•Thermal power plant (It makes use of coal)
•Internal combustion engine plants (makes use of petrol or diesel)
•Gas turbine power plant (makes use of a permanent gas)
•Nuclear power plant (makes use of nuclear fuels)
•Solar power plant (makes use of the suns radiation heat)
• Tidal power plant (makes use of the power of tides in the sea)
•Hydro electric power plant (makes use of the potential energy of water)
•Wind power (makes use of energy available in wind)
•Geothermal power plant (makes use of heat energy available underthe
ground)
3. State the function of the condenser in the steam power plant.
The function of condenser is to condensate the steam coming out of steam
turbine at lowpressure.
4. What is the function of moderator in nuclear power plant?
It is used to reduce the kinetic energy of fast neutrons into slowneutrons
and to increase the probability of chain reaction.
5. What are the materials used as a moderator in a nuclear power plant?
Graphite, heavywater and beryllium are generally used as moderator
6. What are the fuels used in a nuclear power plant.
Fuel of a nuclear reactor should be fissionable material whichcan be defined as
an element or isotope whose nuclei can be caused toundergo nuclear fission by
nuclear bombardment and to produce a fissionchain reaction. It can be one or all
of the following U 235, U 233 and Pu 239
7. List out the factors to be considered for the selection of site for the hydro
electric power plant.
Factors to be considered for the selection oif site for the hydroelteric power
plant are
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Availability of water : Adequqte water must be available with good supply
head
Cost and type of land :Bearing capacity of land should be good to withstand
huge stuructures and equipments
Storage of water :A dam must be constructed to store the large quantity of
water in order to cope up with variations of water availability through out
Transportation facilities : The site should be accessible by rail and road for
easy transportation of equipments and machinery
Pumped storage facilities : pump facilities to reuse water should be
posssible
8. State the reason why the steam power plant is preferred than the other plants.
1.The initial cost of construction of the plant is low compared to
hydroelectric plant
2.The power plant may be located near the load centre, so that the costof
transmission and the losses due to transmission are considerably reduced.
3.The quantity of water in hydroelectric plant depends on nature, such as rain and
rivers. This is not so in the case of thermal power plants
.4.The construction and commissioning of thermal power
plant takeslesser period when compared to hydro electric power plant.
9. What is a cooling tower?
A cooling tower is a heat rejection device, which extracts waste heat to the
atmosphere though the cooling of a water stream to a lower temperature.In
thermal stream plant in order to lower the temperature, water is circulated
around the engine. The water envelopes (water jacket) the engine,the heat from
the cylinder, piston, combustion chamber etc, is carried by the circulating water
and is cooled in the cooling tower.
10. What is the function of a penstock?
Penstock pipe is used to bring water from the dam to
The hydraulic turbine. Penstock pipes are made up of steel
Or reinforced concrete. The turbine is installed at a lower level from the dam.
Penstock is provided with a gate valve at the inlet to completely close the
water supply.
11. What is meant by nuclear fission?
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Uranium exists as an isotope in the form of U 235, U234 and U238. Out of
these isotopes U 235 is more unstable. When a neutron is captured by a nucleus
of an atom of U235, it splits up roughly into two equal fragments and about 2.5
neutrons are released and a large amount of energy (nearly 200 million electron
voltsMeV) is produced. This is called fission process
12. What is the function of a intercooler in gas turbine power plant?
The intercooler is used to reduce the work of the compressor and it is placed
in between the high pressure and low pressure compressor. Intercoolers are
generally used when the pressure ratio is very high. The energy required to
compress the air is proportional to the air temperature at inlet. The cooling of
compressed air in intercooler is generally done by water.
13. Name the different components used in a gas turbine power plant.
The different components used in a gas turbine power plant are
1. Compressor. 2. Intercooler 3. Regenerator 4. Combustion chambers
5. Gas turbine 6. Reheating unit
14. What is radiation shielding.?
A thermal Sheild is provided through steel lining andanother shield is
made of thick concrete surrounding the reactor.This is called radiation shielding.
This shield is used to protect against the harmful rays and fast neutrons.
15. What are the different types of hydro power plants?
Hydro electric power plants are usually classified according
to the available of head of water
•High head power plants
•Medium head power plants
•Low head power plants
16. State the demerits of steam power plant.
1.The fuel (coal or oil) used in thermal power plant will one day get
exhausted since it is a non renewable source of energy that is used
2.It cannot be used as peak load plant, as its part load efficiency decreases very
rapidly with decreasing load.
3.The transportation of fuel is a major problem for power plants located away
from coal fields.
4.The cost of power generation is considerably high compared to hydro-electric
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power plant
.5.The smoke produced by the burning fuel when exhausted into the atmosphere
causes air pollution.6.The life of thermal power plant according to the Electricity
supply act is 25 years and that of hydroelectric plant is 35 years. The efficiency
decreases to less than 10% after its life period.
17. List out the applications of gas turbine power plant.
Applications of gas turbine power plant
•To drive generators and supply loads in steam, diesel or hydro plants
•To work as combination plants with conventional steam boilers
•Thermal process industries
•Petro chemical industries
•Power generation (used for peak load and as stand by unit)
•Aircraft and ships for their propulsion. They are not suitable forautomobiles
because of their very high speeds
18. Name the locations where nuclear power plants were installed in India.
Nuclear power stations in India
• Tarapur Nuclear power station (Bombay) – Boiling water reactor –200 MW
•Rana Pratap Sagar Nuclear power station (Kota in Rajasthan) – Two200 MW
•Kalpakkam Nuclear power station – Two 235 MW – Pressurisedwater reactor
•Narora Nuclear power station (Uttar Pradesh) – Two 235 MW –CANDU reactor
19. Define steam turbine.
A steam turbine is a mechanical device that extracts thermal energy from
pressurized steam and converts it into useful mechanical work. Steam turbine is a
prime mover which converts heat energy in the steam in to mechanical work.
20 List out the main parts of a steam turbine.
The main parts of a steam turbine are
● Nozzle
● Rotor
● Rotor blades
21. How steam turbines are classified.
The steam turbines are classified into
1. Impulse turbine
2. Reaction turbine
22. Differentiate between impulse and reaction turbine.
S.No Impulse turbine Reaction turbine
1. It consists of nozzles and Steam passes over the blades with
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moving blades pressure and kinetic energy.
2. Steam expands completely
in the nozzle.
Steam expands both in fixed and
moving blades.
3. Pressure drops in nozzles
and remain constant in
moving blades
Pressure drop occurs gradually
and continuously in both fixed and
moving blades
4. Power developed is less Power developed is more
5. Low efficiency High efficiency
6. Occupies less space per
power unit
Occupies more space per power
unit
23. Relative velocity of a steam increases in a reaction turbine – Justify.
Relative velocity of a steam increases in a reaction turbine as there is a
continuos expansion of the steam.
BCM
Part A
UNIT III – Power Plant Engineering, Pumps and Turbines.
1. Define power plant.
2. What are the different types of power plants?
3. State the function of the condenser in the steam power plant.
4. What is the function of moderator in nuclear power plant?
5. What are the materials used as a moderator in a nuclear power plant?
6. What are the fuels used in a nuclear power plant.
7. List out the factors to be considered for the selection of site for the hydro electric power plant.
8. State the reason why the steam power plant is preferred than the other plants.
9. What is a cooling tower?
10. What is the function of a penstock?
11. What is meant by nuclear fission?
12. What is the function of a intercooler in gas turbine power plant?
13. Name the different components used in a gas turbine power plant.
14. What is radiation shielding.
15. What are the different types of hydro power plants?
16. State the demerits of steam power plant.
17. List out the applications of gas turbine power plant.
18. Name the locations where nuclear power plants were installed in India.
19. Define steam turbine.
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20 List out the main parts of a steam turbine.
21 How steam turbines are classified.
22. Differentiate between impulse and reaction turbine.
23. Relative velocity of a steam increases in a reaction turbine – Justify.
UNIT IV
1. What is an engine?
2. What are the different types of heat engine?
3. What is meant by SI Engine.
4. What is meant by CI Engine.
5. List out the main components of a SI Engine.
6. What is a four stroke cycle engine?
7. What is the function of a carburetor?
8. What is the fundamental difference between two stroke and four stroke engine.
9. Why fuel is injected in a CI Engine.
10. Mention the different types of ignition systems used in SI engine.
11. What is the function of a choke, in a petrol engine?
12. What is the function of a spark plug, in a petrol engine?
13. What is the function of a fuel pump in a diesel engine?
14. Define fuel injector.
15. What are the different types of cooling system used in IC engines.
16. Define lubrication.
17. Mention some engine parts, that require lubrication.
18. What are the different types of lubrication systems in IC Engines.
19. How boilers are classified.
20. List the advantages of high pressure boilers.
21. How modern boilers differ from olden day boilers.
22. What is the function of an economiser.
23. List out the boiler mountings.
24. What is the difference between boiler mountings and accessories.
25. What is the function of a super heater.
26. What is the function of a air pre-heater.
27. Give few examples for water tube boiler.
28. Give few examples for fire tube boiler.
UNIT V
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1. Define Refrigeration.
2. What is a refrigerator?
3. Define Refrigerant.
4. Give some examples for refrigerant.
5. Define COP
6. List out the properties of a good refrigerant.
7. State the function of a compressor in refrigeration system.
8. Give the applications of a refrigeration.
9. Define air conditioning.
10. Define Relative humidity.
11. Define DBT
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12. Define WBT
13. List out the types of air conditioning.
14. Define Dew point temperature.
15. Define psychrometry.
16. Define relative humidity.
17. Differentiate between humidification and dehumidification.
18. What is the function of a capillary tube.
19. Differentiate between window air conditioner and package type air conditioner.
20. Draw the layout of a domestic refrigerator.
Part B
UNIT III
1. Draw the layout of the steam power plant and explain.
2. Sketch the diesel power plant and explain its working principle, also state its merits and
demerits.
3. Draw the general arrangement of a nuclear power plant and explain its working. List out its
merits and demerits.
4. Explain how energy conversion is taking place in a solar power plant, with a
line sketch.
5. Draw the layout of a wind mill and state its advantages and disadvantages.
6. Give the schematic layout of a hydro electric power plant and explain the function of its each
component.
7. What is the principle of a tidal power generation. Also explain the low tide and
high tide systems.
8. Define a centrifugal pump, explain the working of a single stage pump with a sketch.
9. Explain the construction and working principle of a reciprocating pump with neat sketch.
Also state its applications.
10. With pressure velocity diagram explain the working of a single stage impulse
turbine.
11. With pressure velocity diagram explain the working of a reaction turbine.
12. Differentiate between impulse and reaction turbine.
13. With a neat sketch, briefly explain about Lamont Boiler
14. Explain the construction and working principle of Cochran Boiler.
15. Name the important boiler mountings and briefly explain their functions.
16. Name some of the boiler accessories, and explain their functions with sketches.
UNIT IV
1. With neat sketch, explain the major parts of an IC Engine.
2. Explain the working principle of four stroke petrol engine with neat sketches.
3. With neat sketches, explain the working principle of two stroke petrol engines.
5. Explain the working principle of a four stroke Diesel engine with neat sketch.
6. With line diagram, explain the working principle of two stroke diesel engine.
7. Discuss the advantages and disadvantages of a CI engines over SI Engines.
8. Compare two stroke and four stroke engines.
9. Compare air cooling and water cooling system used in IC engines.
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10. Explain briefly about knocking and detonation.
11. With a neat sketch briefly explain about fuel injector.
UNIT V
1. With a neat sketch explain the layout of a window air conditioning.
2. Draw the layout of a vapour compression refrigeration system, and explain the working
principle of it.
3. With a simple circuit diagram, explain the working principle of the vapour
absorption refrigeration system.
4. Mention and describe the different types of refrigerants used.
5. With a neat diagram, briefly explain about the split type room air conditioner.
6. Draw the layout of multi split air conditioner, and explain the working principle of it.
7. Write down the definitions of the following:
(a) DBT (b) WBT (c) Relative Humidity (d) Dew point temperature (e) humidity (f)
Psychrometry (g) COP
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GE2152-BASIC MECHANICAL ENGINEERING-2 MARKS Questions with Answers

UNIT-III

POWER PLANTS, PUMPS AND TURBINES

1. What are the classifications of power plants based on non-renewable source of energy?

·         Steam power plant.

·         Nuclear power plant.

·         Diesel power plant.

·         Gas turbine power plant.

2. What are the classifications of power plants based on renewable source of energy?

·         Hydro-electric power plant.

·         Solar power plant.

·         Wind power plant.

·         Tidal power plant.

3. Write the steam power plant circuits.

·         Coal and ash

·         Air and flue gas

·         Feed water and steam.

·         Cooling water circuit.

4. What is the function of economiser?

         The economiser is used to pre-heat the feed water.

5. What is the function of super heater?

          The function of super heater is used to super heat the saturated steam and to supply the

          steam to turbine.

6. What are the advantages of thermal power plants?

·         Power can be generated continuously.

·         Power plant can withstand the varying load.

·         Initial cost low

·         The construction period for the power plant is minimum.

·         7. What are the dis-advantages of thermal power plants?

·         Power generation cost is high.

·         Handling of coal is a major problem.

·         Handling of coal is a major problem.

·         Life of the plant is low.

·         Plant efficiency is less.

8. What is the function of penstock?

      Penstock is the pipe made up of steel or concrete used to carry water from the dam to

      power house.

9. What is meant by trash rack?

Trash rack is provided to prevent the debris from getting entry to power house. This

consists of number of steel bars and it is placed across the intake to prevent debris.

10. What is meant by draft tube?

Draft tube is an integral part of reaction turbine. Draft tube connects the runner exit to

tail race. The area of the draft tube is same as that of the runner to avoid shock and is circular

cross section. The water after doing work on the turbine runner passes through the draft tube.

11. Write the advantages of hydro electric power plant.

o This plant uses water for power generation.

o Water is easily available.

o Beside power generation, this also provides benefits like irrigation, flood control, affore

station-culture.

o Fuel cost is eliminated.

o Plants are automated and hence operating labor cost is low.

12. Write the dis-advantages of hydro electric power plant.

o The plant disrupts the surrounding aquatic ecosystems.

o Initial cost of plant is very high.

o Failure of dams is potentially serious.

o Large investments, long gestation periods are major issues.

13. Draw the layout of diesel power plant.

Air compressor

Diesel engine

Water pump

Fuel storage Oil cooler

Feed pump ,Layout of diesel power plant

14. What are the advantages of diesel power plants?

o Power plant can be easily installed.

o The plant is smaller in size and fuel handling and storage is easier.

o Quick starting and easy pickup is possible.

o No ash disposal problem.

15. What are the dis-advantages of diesel power plants?

o Fuel is more expensive.

o Repair and maintenance cost is high.

o Capacity of diesel engine is low.

o Lives of plants are low.

16. What is the function of re-generator?

The heat obtained in the exhaust gases of LPT is utilized in the re-generator for

transferring heat to the cold air coming out of HPC.

17. What is the function of intercooler?

This reduces the work of compressor; hence the power spent by compressor is less when

the air is cooled.

18. Write the advantages of gas turbine power plants.

o The capital cost of plant is low.

o This can be quickly commissioned.

o It requires less space.

o Capacity to use wide variety of fuels.

19. Write the advantages of gas turbine power plants

o About two third of the power developed by the turbine is used to drive the compressor.

Hence net output of plant is low.

o Low effiency.

o Needs special cooling arrangements.

o Operating temperature is high of the order of 20000C.

20. Define nuclear fission.

Nuclear fission is defined as the splitting up the nucleus of an atom into parts where

enormous amount of energy is released and this energy is used to generate power.

21. Write the function of moderator

In the chain reaction, the neutrons produced are fast moving neutrons. They are less

effective in causing fission of U235 and try to escape from the reactor. To improve the utilization

of these fast neutrons, their speed is reduced in this moderator.

22. What is the function of control rods?

The energy produced in the reactor during chain reaction is enormous. If this is not

controlled properly entire core and structure may melt and radioactive rays may come out of the

reactor. The control rods do this control.

23. Explain about Biological shielding of nuclear reactor.

During fission reaction alpha particles, beta particles, gamma rays and neutrons are

produced. These radioactive rays are harmful to operating men. To protect from such harmful

effects, thick concrete shielding is provided all round the reactor.

24. What are the advantages of nuclear power plant?

o Requires less space compared to steam power plant.

o Fuel required is negligible compared to coal requirement in steam power plant.

o Fuel transport cost is less.

o Cost of Erection is less.

o Water required is very less.

25. What are the dis-advantages of nuclear power plant?

o Initial cost is higher.

o Not suitable for varying load condition.

o Maintenance cost is higher.

o Trained workers / Engineers are required to handle the operation.

26. What is pump?

Pump is a mechanical device which is used for moving liquids or gases from lower

pressure to higher pressure. In a pump mechanical forces are used to move the fluids.

27. Write the classification of pump with examples.

o Rotodynamic eg; Centrifugal pump.

o Positive displacement pump eg: Reciprocating pump

28. What is meant by centrifugal pump?

Centrifugal pump is rotodynamic pump which uses the mechanical energy of the rotating

impeller to increase the velocity of a fluid by the application of centrifugal force. The fluid

enters the pump impeller along the rotating axis and gets accerelated.flows radially outwards

into a casing and exits through the piping system. It is generally used for large discharge

through smaller heads.

29. What is meant by reciprocating pump?

A reciprocating pump is a positive displacement pump in which liquid is sucked and

then it is pushed or displaced due to the thrust exerted on it by a moving member which results

in lifting height. The pump has one or more chamber which are alternately fitted with liquid to

be pumped and then emptied again. Thus reciprocating action is being continued within the

pump and hence, the pump is called reciprocating pump.

30. What are the types of reciprocating pump?

o Single acting reciprocating pump

o Double acting reciprocating pump

31. What is priming?

Priming is the operation of filling up of water in the suction pipe, casing and a portion of

delivery valve to remove the air present inside. If any air is present, the pressure developed

across the impeller will not be sufficient to suck the water from the sump. The delivery valve is

kept closed during priming.

32. What are the types of casing?

o Volute casing.

o Vortex casing.

o Diffuser casing.

33. Defined turbine.

A turbine is defined as a hydraulic machine which converts hydraulic energy into

mechanical energy and this mechanical energy is used to use to run an electrical generator

which is directly coupled to the shaft of the turbine. Thus, mechanical energy is converted into

electrical energy. A simple turbine will have one moving part and a rotor assembly. The rotating

system is called a runner in a turbine.

34. What is meant by impulse turbine with example?

In this energy is available is only kinetic energy, then the turbine is known as impulse

turbine. Eg: Pelton wheel turbine.

35. What is meant by reaction turbine with example?

In this the energy available is kinetic energy and pressure energy, then the turbine is

known as reaction turbine. When the fluid through the runner, it is under pressure and the

pressure energy goes on changing into kinetic energy. Eg: Francis turbine

36. Write the function of casing.

o To prevent splashing of water.

o To lead the water to the tail race.

o To act as a safeguard against any accidents.

                                                               

                                                   UNIT-IV

                               INTERNAL COMBUSTION ENGINES

1. What is meant by I.C. engine?

In this type of engine, combustion of fuel takes place within the cylinder. This type of engine

includes gas engine, petrol engines and diesel engines. These are generally used for road

vehicles, locomotives, and aircraft and for other industrial applications.

2. Write the classification of I.C. engines.

Based on ignition:

o Spark ignition

o Compression ignition.

Based on fuel:

o Petrol engine

o Diesel engine.

Based on cooling system:

o Air cooled

o Water cooled.

 3. What are the basic components of I.C. engines?

o Cylinder block.

o Cylinder head.

o Cylinder liners.

o Crankcase.

o Piston.

 4. What is meant by Top dead centre?

This refers to the position of the crankshaft when the piston is in its top most position

i.e., the position closest to the cylinder head.

5. What is meant by Bottom dead centre?

This refers to the position of the crankshaft when the piston is in its lowest position i.e.,

the position closest to the cylinder head.

6. Define stroke.

Stroke is defined as the distance traveled by the piston while moving from T.D.C to the

B.D.C.

 7. What is meant by clearance volume?

The volume of cylinder above the piston when it is in the T.D.C. position is referred to

as Clearance volume (Vc).

8.What is compression ratio?

This indicates the extent to which the charge in the engine is compressed. This is

calculated as the ratio of the volume above the piston at B.D.C to the volume above the piston at

T.D.C. If V is the compression ratio

VS + VC

V = --------------------VC

9. What is mean effective pressure?

This Is the average pressure throughout the whole power stroke. The cylinder pressure

varies considerably during power stroke. Thus it is more helpful to refer to the mean pressure

instead.

10. Define Engine torque.

It is defined as the force of rotation acting about the crankshaft axis at given instant of

time.

T = Fr

11. Define Scavenging.

It is defined as a process of forcing out the exhaust gases from the cylinder by admitting

the fresh charge into the cylinder. This action takes place in two-stroke cycle engines.

12. Write any two differences between two stroke and four stroke engines.

S.No	Two stroke	Four stroke
1	For each revolution of crank shaft one power stroke is produced	For two revolution of crank shaft one power stroke is produced
2	Uniform torque is obtained. Hence a lighter flywheel can be used	Non-uniform torque is obtained. Hence a heavier flywheel can be used

13. Write any two differences between petrol and diesel engines.

S.No                                             Petrol engines                                                        diesel engines

1                                 Operating speed is more. Speed                                  Operating speed is more. Speed                                                                                                                           range is 400 to 3500 rpm.                                range is 3000 to 6000 rpm.

2                                   Produce less noise.                                                   Produce less noise.

3                                  Specific fuel consumption is more.                        Specific fuel consumption is more.

14. Write the basic components in the Fuel Feed System

o Tank

o Feed pump

o Filter

o Injection pump

o Injector

o Leak off pipe

 15. Define Carburettor.

The carburetor is a device for atomizing and vaporizing the fuel and mixing it with the

air in varying proportions to suit the changing conditions of spark ignition engines. The air fuel

mixture so obtained from the carburetor is called the combustible mixture.

16. What are the main functions of a carburetor?

o It preserves fuel at a constant head.

o It vaporizes and atomizes the fuel and mixes it with the air. Vaporization means the

change of fuel from a liquid to a vapour where as ‘atomization’ is the breaking up of fuel

by mechanical system, so that every small particle of the fuel is surrounded by air.

o It provides and controls the amount and strength of air-fuel mixture under varying

conditions of load and speed of the engine.

o It provides easy starting with the engine in cold

o It ensures the engine to run slowly without missing and without undue wastage of fuel,

o It provides maximum acceleration without hesitation to pick up speed when the throttle

is suddenly or slowly opened.

17. Write the basic components in the carburetor.

o Venturi

o Throttle valve

o Choke valve

o Fuel jet.

 18. What are the functions of Fuel injection pump?

In diesel engine, the fuel consists of a cylindrical barrel having two ports called supply

port and spill port. A spring loaded delivery valve is provided at the top of the barrel for fuel

delivery.

19. What are the functions of Fuel injector?

The purposes of the fuel injector is to injector a small volume of fuel in a fine spray and,

to assists in bringing each droplet into contact with a sufficient oxygen to give quick and

complete combustion.

20. Write the types of Ignition system.

o Battery ignition system (or coil ignition system)

o Magneto ignition system.

21. Draw the layout of coil Ignition system.

Coil Ignition system

22. Draw the layout Magneto Ignition system.

Magneto Ignition system

23. Define spark plug.

Spark plug is defined as a device which is used to ignite the compressed air-fuel mixture

by producing an electric spark. It is usually mounted on the cylinder head.

24. Write the basic components of spark plug.

o Insulator.

o Central electrode.

o Earth electrode.

o Metallic shell.

o Gasket.

25. What are the purposes of cooling system?

o To maintain smooth running of engine.

o To avoid the distortion of engine parts.

o To avoid pre-ignition of charge.

o To maintain the temperature of engine within the limit.

o To maintain the strength of the cylinder and piston

26. What are the types of cooling system?

o Direct cooling or Air cooling.

o Water cooling.

27. What are the advantages of air cooling system?

o The design is simple and occupies less space.

o Low cost.

o Less weight.

o Warming the engine is easier.

28. What are the types of water cooling system?

o Thermo-siphon or Natural circulation system.

o Forced circulation system.

29. Write about lubrication system.

Lubrication is the process of applying the lubricant between the surfaces of contact of

two moving parts.

30. What are the purposes of lubrication system.

o To reduce the friction between moving parts.

o To minimize the vibration.

o To reduce the wear and tear.

o To reduce the corrosion and carbon deposits.

o To reduce the heat of moving parts.

31. What are the types of lubrication system?

o Petroil or Mist lubrication.

o Wet sump lubrication.

32. What is meant by Boiler?

A boiler is a closed vessel in which water or other fluid is heated. The heated or

vaporized fluid exits the boiler for use in various processes or heating applications.

33. What is the function of Boiler?

The function of the boiler is to evaporate water into steam at a pressure higher than the

atmospheric pressure. Water free from impurities such as dissolved salts, gases and non soluble

solids should be supplied to boilers. This is done by suitable water treatment. Steam is useful for

running steam turbines in electrical power stations.

34. Write the classification of boilers.

o Fire tube boilers.

o Water tube boilers.

35. Write the two differences between Fire tube and water tube boiler.

S.No	Fire tube boiler	water tube boiler
1	Hot gasses pass through the tubes, water surrounds them
		Water pass through the tubes, hot gases surrounds them
2	Used for low pressure steam (say 10bar)	Used for medium to high pressure steam
3	Thermal efficiency low	Thermal efficiency high

36. What are the advantages of steam boiler?

o Cost of production is cheap when compared with other boilers.

o Less space is required.

o Fuel used is cheaper.

o Steam engines can work under overload of 25percent continuously.

37. What are the dis-advantages of steam boiler?

o Water requirement is more.

o Required more time for installation.

o Maintenance and operating costs are high.

o Coal handling is difficult.

                                                                UNIT-V

                                REFRIGERATION AND AIR CONDITIONING SYSTEM

1. What is Refrigeration?

Refrigeration is the process of removing heat from an enclosed space or from a

substance, under controlled conditions and moving the heat to an unobjectional place.

2. What is meant by refrigerator?

A refrigerator is a machine that removes heat from a low temperature region. Since

energy cannot be destroyed, the heat taken in at a low temperature must be dissipated to the

surroundings.

3. State the second law of Thermodynamics.

Second law of Thermodynamics states that heat will not pass from cold region to a warm

one without the aid of an external agent. Therefore, a refrigerator will require this external agent

or energy input, for its operation.

4. What is meant by refrigerant? Give some examples.

The substance which absorbs heat the materials placed in refrigerator is called

refrigerant.

E.g.: Freon-12, Freon-22, and Ammonia.

5. Define Ton of refrigeration.

The capacity if air conditioner and ice plant is represented in Tons.

1ton = 3024 kilo calories/hr

6. What is meant by sensible heat?

The amount of heat removed from the body or given to the body to decrease or increase

its temperature is called sensible heat.

7. Write the different kinds of heat transfer modes with examples.

o Conduction E.g.: Metal and other solids

o Convection E.g.: Heat through fluid

o Radiation E.g.: Sun light

8. Define Co-efficient of performance.

The purpose of the refrigerator is to remove heat from the cold region while requiring as

little external work as possible.

COP = Heat exerted / Work supplied

9. What are the applications of refrigeration?

o Preserving foodstuffs in homes, restaurants and in large warehouses.

o Used to liquefy gases like oxygen, Nitrogen, Propane and Methane.

o Preserving dairy products, fruits and vegetables.

o Preserving Meats, poultry and fish.

10. What are the types of refrigeration system?

o Vapour compression refrigeration system

o Vapour absorption refrigeration system

11. Write the difference between Vapour compression and Vapour absorption refrigeration system.

S.No	Vapour compression system	Vapour absorption system
1	The capacity of the system is above 1000tons	Maximum capacity is limited to 1000tons
2	The operation is quit	The operation is noisy
3	Maintenance cost is low	Maintenance cost is high

12. Write the classification of refrigerants with examples.

o Primary refrigerants E.g. R12, Ammonia, Freon.

o Secondary refrigerants E.g. Co2, CaCl2, NaCl

13. What is meant by Air conditioning?

Air conditioning is the process of controlling the temperature and humidity of air by

heating or cooling, humidifying or dehumidifying, and filtering the atmospheric air, and thus

creating a healthy and comfortable condition for human beings.

14. What are the applications of Air conditioning?

o Providing relatively constant indoor environment for a building as per human comfort.

o For taller buildings where natural ventilation is not possible due to high

o In hospital operation theatres, to reduce infection risk.

15. Define Psychometry

It is the science which deals with the study of the behavior of air and water vapour

mixture.

16. Define dry bulb temperature.

It is the temperature of air measured by an ordinary thermometer.

17. Define Wet bulb temperature.

It is the temperature of air measured by thermometer when its bulb is covered with a wet

cloth and is exposed to atmospheric air.

18. Define dew point temperature.

It is the temperature at which the moisture present in the air begins to condense. It

corresponds to the saturation temperature of water vapour in the mixture of air and water

vapour.

19. Write the types of Air conditioner?

o Window air conditioner

o Package air conditioner

o Centralised air conditioner

o Split type air conditioner

20. Define relative humidity

It is defined as the ratio of water vapour present in the given amount of air to the mass of

water vapour present in the same volume under same temperature conditions.

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