lab manual elements of mechanical engineering (2110006) · pdf fileelements of mechanical...

Lab ManualElements of Mechanical Engineering(2110006)

Department of Mechanical EngineeringDarshan Institute of Engineering andTechnology, Rajkot.

Darshan Institute of Engineering & Technology

Certificate

This is to certify that Mr./Ms.____________________________________

Enrollment No. ________________Branch_____________________________

Semester 1st & 2nd has satisfactory completed the course in the subject Elements

of Mechanical Engineering in this institute.

Date of Submission: -___ / ___ / ______

Staff in Charge Head of Department

DARSHAN INSTITUTE OF ENGG. & TECH.

Department of Mechanical Engineering

B.E. Semester – I

Elements of Mechanical Engineering(2110006)

List of Experiments

Sr.

No.Title Date of

PerformanceDate of

submission Sign Marks(Out of10)

1To understand construction andworking of various types of boilers.

2To learn about various BoilerMountings & Accessories.

3To understand construction andworking of I. C. Engines.

4To study about engine performanceparameters.

5To understand construction andworking of different types of pumps.

6

To understand construction andworking of different types of aircompressors.

7Demonstration of domesticrefrigerator.

8

To understand construction, workingand applications of different types ofcoupling, clutch and brake.

9Demonstration of various types ofpower transmission elements.

Elements of Mechanical Engineering (2110006)Department of Mechanical EngineeringDarshan Institute of Engineering & Technology Page 1

EXPERIMENT-1

Objective

To understand construction and working of various types of boilers

1.1 Introduction

Steam boiler may be defined as “A closed pressure vessel in which steam is generated withcapacity exceeding 25 liters gauge pressure greater than or equal to 1 kg/cm2, and water Isheated at 100°C or above. The steam produced may be supplied:1) For generating power in steam Engine or steam turbines.2) At low pressures for industrial process work in cotton mills, sugar factories, etc.3) For producing hot water for supply of hot water and for heating the buildings in cold

weather.

1.2 Classification of Steam Boilers

1.2.1 According to relative position of water and hot gases.Fire Tube boiler - hot gases pass through fire tubes which are surrounded by waterWater tube - water flows inside the tubes and the hot flue gases flow outside the tubes.

1.2.2 According to the axis of the shellVertical boiler – the axis of the shell is vertical.Horizontal boiler – the axis of the shell is horizontalInclined boiler – the axis of the boilers is inclined.

1.2.3According to the method of firingExternally fired boilers – furnace is located outside the shell.Internally fired boilers – furnace is located inside the shell, means combustion takes placeinside the boiler shell.

1.2.4 According to the Method of Water circulationForced Circulation boilers - water is circulated by pumps which is driven by motor andNatural Circulation boilers - water is circulated by natural convection currents which areset up due to the temperature difference produced by the application of heat.

1.2.5 According to the Pressure of steamHigh pressure – boilers working pressure is more than 25 bars. Example: Babcock andWilcox boilerMedium pressure boilers – working pressure is 10 to 25 bars. Example: Lancashire andlocomotive boilerLow pressure boilers – working pressure is 3.5 to 10 bars. Example: Cochran and Cornishboiler.

1.2.6 According to the mobility of boilerStationary boilers – it is used for stationary plants.Mobile boilers – it can move from one place to another.


1.2.7According to the number of tubes in the boilerSingle tube boilers – they have only one fire or water tube.Multi tube boilers – they have more than one fire or water tubes.

1.3. General terms (parts) used in Steam Boiler

1.3.1Cylindrical shellIt is made up of steel plates bent into cylindrical form and rewetted and welded together.The ends of shell are closed by means of plates in different shapes. It should have sufficientcapacity to contain water and steam.

1.3.2 Combustion chamberIt is the space, generally below the boiler shell, meant for burning fuel in order to producesteam from the water contained in the shell.

1.3.3 GrateIt is a platform, in the combustion chamber, upon which fuel is burnt. The grate consists ofcast iron bars which are spaced apart so that air can pass through them.

1.3.4 FurnaceIt is a chamber formed by the space above grate and bellows the boiler shell in whichcombustion take place. It is also called a Fire box.

1.3.5 Fire HoleIt is the hole through which coal is added to the furnace.

1.3.6 Ash Pit (ash pan)It is the area in which the ash of burnt coal is collected.

1.3.7 Smoke chamber (smoke box)The waste gases are collected here and then releases to the chimney and then toatmosphere.

1.3.8 Man HoleIt is a hole provided on to the boiler shell so that a workman can go inside the boiler forinspection.

1.3.9 Hand HolesIt is a hole provided on the shell to give to give east access for the purpose of cleaning thewater tubes or some other internal parts of boiler.

1.3.10 Mud boxIt collects all impurities present in the water. It is at the bottom of the barrel or shell. Theseimpurities are removed time to time by help of blow off cock.

1.3.11 Steam collecting pipeWhen the steam leaving the boiler, it contains certain amount of water.Antipriming pipe isused to separate water particles from the steam and to collect dry steam from boiler.


Questions:

(1) Explain Working of following boiler with neat sketch:a) Cochran boilerb) Babcock and Wilcox boilerc) Lancashire boiler

(2) Give difference between fire tube (Cochran) and water tube (Babcock Wilcox) boiler.


Conclusion:

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EXPERIMENT – 2Objective

To learn about various Boiler Mountings & Accessories

MountingsThese are the safety devices for the safe working of steam boiler and they are mounted on thesteam boiler like Water indicator valve, pressure gauge, fusible plug, etc.

AccessoriesThese devices are used for increasing the efficiency of boilers. They are integral parts of theboiler and are not mounted on the boiler. They include Super heater, Economizer, etc.

2.1 List of Boiler Mountings & Accessories

According to IBR the following mountings should be fitted to the boilers’1) Two Safety valves2) Two water level indicators3) A pressure gauge4) A Steam stop valve5) A feed check valve6) A blow off cock7) An attachment of inspector’s test gauge8) A man hole9) Mud holes or sight holes

Commonly used boiler accessories are as1) Feed pumps2) Injector3) Economizer4) Air preheater5) Superheater6) Steam separator7) Steam trap


Questions:

(1) What are the purposes of mounting? Explain working of following with neat sketch.

a) Water level indicatorsb) Fusible plugc) Pressure gauged) Spring loaded safety valvee) Feed check valve

(2) What are the purposes of accessories? Explain working of following with neat sketch.

a) Economiserb) Super heaterc) Air pre-heater


Conclusion:

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EXPERIMENT - 3

Objective

To understand construction and working of I. C. Engines

3.1 IntroductionIn 1876 four stroke engine based on Otto cycle was developed by a German engineerNikolous Otto, Which revolutionized the development of internal combustion engines andare even used till date. Diesel engine was developed by another German engineer RudolfDiesel in the year 1892.Engine refers to a device which transforms one form of energy into the other form. “Heatengine is a modified form of engine used for transforming chemical energy of fuel intothermal energy and subsequently for producing work."Heat engines may be classified based on where the combustion of fuel takes place. i.e.whether outside the working cylinder or inside the working cylinder.

(a) External Combustion Engines (E.C. Engines)

(b) Internal Combustion Engines (I.C. Engines)

3.2 Comparison of I.C. Engines and E.C. Engines

Sr.N0 I.C. Engine E.C. Engine

1.Combustion of fuel takes place inside thecylinder.

Combustion of fuel takes placeoutside the cylinder

2.Working fluid may be Petrol, Diesel &Various types of gases.

Working fluid is steam

3. Require less space Require large space4. Capital cost is relatively low. Capital cost is relatively high.5. Starting of this engine is easy & quick Starting of this engine requires time.6. Thermal efficiency is high. Thermal Efficiency is low.

7.Power developed per unit weight of theseengines is high.

Power Developed per unit weight ofthese engines is low

8. Fuel cost is relatively high. Fuel cost is relatively low.


3.3 Classification of I.C. EnginesI.C. Engines may be classified according to,

a) Type of the fuel used as :(1) Petrol engine(2) Diesel engine(3)Gas engine(4) Bi-fuel engine (Two fuel engine)

b) Nature of thermodynamic cycle as :(1) Otto cycle engine(2) Diesel cycle engine(3) Duel or mixed cycle engine

c) Number of strokes per cycle as :(1) Four stroke engine(2) Two stroke engine

d) Method of ignition as :(1) Spark ignition engine (S.I. engine)Mixture of air and fuel is ignited by electric spark.(2) Compression ignition engine (C.I. engine)The fuel is ignited as it comes in contact with hot compressed air.

e) Method of cooling as :(1) Air cooled engine(2) Water cooled engine

f) Speed of the engine as :(1) Low speed(2) Medium speed(3) High speed

g) Number of cylinder as :(1) Single cylinder engine(2) Multi cylinder engine

h) Position of the cylinder as :(1) Inline engines(2) V – engines(3) Radial engines(4) Opposed cylinder engine(5) Opposed piston engine

3.4 Engine detailsThe various important parts of an I.C. engine are shown in figure.


3.4.1. CylinderIt is the heart of the engine in which the fuel is burnt and the power is developed. Cylinderhas to withstand very high pressure and temperature because the combustion of fuel iscarried out within the cylinder. Therefore cylinder must be cooled. The inside diameter iscalled bore. To prevent the wearing of the cylinder block, a sleeve will be fitted tightly inthe cylinder. The piston reciprocates inside the cylinder.

3.4.2 Cylinder headCylinder head covers top end of cylinder. It provides space for valve mechanism, sparkplug, fuel injector etc.

3.4.3 PistonThe piston is a close fitting hollow cylindrical plunger reciprocating inside the cylinder.The power developed by the combustion of the fuel is transmitted by the piston to the crankshaft through connecting rod.

3.4.4 Piston RingsThe piston rings are the metallic rings inserted into the circumferential grooves provided atthe top end of the piston. These rings maintain a gas-tight joint between the piston and thecylinder while the piston is reciprocating in the cylinder.

3.4.5 Piston pin or Gudgeon pinIt is the pin joining small end of the connecting rod and piston. This is made of steel byforging process.

3.4.6 Connecting RodIt is the member connecting piston through piston pin and crank shaft through crank pin. Itconverts the reciprocating motion of the piston into rotary motion of the crankshaft. It ismade of steel by forging process.

3.4.7 Crank and CrankshaftThe crank is a lever that is connected to the big end of the connecting rod by a pin jointwith its other end connected rigidly to a shaft, called crankshaft. It rotates about the axis ofthe crank shaft and causes the connecting rod to oscillate.

3.4.8 ValvesEngine has both intake and exhaust type of valves which are operated by valve operatingmechanism (Refer Fig. 3.5). The valves are the device which controls the flow of the intakeand the exhaust gases to and from the engine cylinder.

3.4.9 FlywheelIt is a heavy wheel mounted on the crankshaft of the engine. It minimizes cyclic variationin speed by storing the energy during power stroke, and same is released during otherstroke.

3.4.10 CrankcaseIt is the lower part of the engine, serving as an enclosure of the crankshaft and also as asump for the lubricating oil.

3.4.11 CarburetorCarburetor is used in petrol engine for proper mixing of air and petrol.


3.4.12 Fuel pumpFuel pump is used in diesel engine for increasing pressure and controlling the quantity of

fuel supplied to the injector.3.4.13 Fuel injector

Fuel injector is used to inject diesel fuel in the form of fine atomized spray under pressureat the end of compression stroke.

3.4.14 Spark plugSpark plug is used in petrol engine to produce a high intensity spark for ignition of airfuel mixture in the cylinder.

3.5 Engine Terminologies

3.5.1 Bore:The inner diameter of the engine cylinder is called a bore.

3.5.2 Stroke:It is the linear distance traveled by the piston when it moves from one end of thecylinder to the other end. It is equal to twice the radius of the crank.

3.5.3 Dead Centers:In the vertical engines, top most position of the piston is called Top Dead Centre (TDC).When the piston is at bottom most position, it is called Bottom Dead Centre (BDC).In horizontal engine, the extreme position of the piston near to cylinder head is called InnerDead Centre (I.D.C.) and the extreme position of the piston near the crank is called OuterDead Centre (O.D.C.).

3.5.4 Clearance Volume (Vc)It is the volume contained between the piston top and cylinder head when the piston is attop or inner dead centre.

3.5.5 Stroke volume (swept volume)It is volume displaced by the piston in one stroke is known as stroke volume or sweptvolume.Let, Vs = stroke volume, L = stroke length, d = Bore= 4

3.5.6 Compression RatioThe ratio of total cylinder volume to clearance volume is called the compression ratio (r)of the engine.Total cylinder volume = Vc + Vs

Compression Ratio, =∴ = +

For petrol engine r varies from 6 to 10 and for Diesel engine r varies from 14 to 20.


3.5.7 Piston speedIt is average speed of piston. It is equal to 2LN, where N is speed of crank shaft in rev/sec.∴ , = 260Where,L = Stroke length, mN = Speed of crank shaft, RPM

Questions:(1) Explain Four stroke petrol engine (Spark ignition four stroke engine OR Otto four

stroke engine ) with sketch.(2) Explain working of two stroke petrol engine with diagram.(3) Explain working of four stroke diesel engine (compression ignition engine ) with

sketch.(4) Give difference between petrol and diesel engine.


Conclusion:

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EXPERIMENT - 4Objective

To study about engine performance parameters

4.1 Indicated power

The power produced inside the engine cylinder by burning of fuel is known as Indicatedpower (I.P.) of engine. It is calculated by finding the actual mean effective pressure., =

Where,

a = Area of the actual indicator diagram, cm2

l = Base width of the indicator diagram, cm

s = spring value of the spring used in the indicator, N/m2/cm4.1.1 Indicated power of a Four-stroke engine

Let,

Pm = Mean effective pressure, N/m2

L = Length of stroke, m

A = Area of cross section of the cylinder, m2

N = RPM of the engine crank shaft

n = Number of power strokes per minute

Work produced by the engine per cycle,

= [Mean force acting on the piston] X [Piston displacement in one stroke]× × .Work produced by the engine per minute,

= [Work produced by the piston per cycle] X [Number of power stroke per minute]× × ×In four-stroke I.C. engines, number of power stroke per minute will be equal to half ofRPM because we get one power stroke in two revolutions of the crank shaft.

i.e. = 2⁄Work produced by the engine per minute,× × × 2

( . . ) = 60 × 2


∴ . . = 60000 × 24.1.2 Indicated power of a two stroke I.C. engine

In two stroke I.C. engine, the number of power strokes per minute will be equal to RPM ofcrank shaft

i.e. n = N

Indicated power of a two stroke I.C. engine is given by∴ . . = 600004.2 Brake Power (B.P.)

It is the power available at engine crank shaft for doing useful work. It is also known asengine output power. It is measured by dynamometer.It can be calculated as follows:Let,W = Net load acting on the brake drum, NR = Radius of the brake drum, mN = RPM of the crank shaftT = Resisting torque, NmPmb = Brake mean effective pressure

∴ = ×And . . = 260000 = 60000The piston connecting rod and crank are mechanical parts, moving relative to each other.They offer resistance due to friction. Therefore a certain fraction of power is lost due tofriction of the moving parts. The amount of the power lost in friction is called frictionpower. The friction power is the difference between the I.P. and B.P.

= . . − . .4.3 Efficiencies4.3.1 Mechanical efficiency:

It is defined as the ratio of the brake power and the indicated power. Mechanicalefficiency is indicator of losses due to friction.= . .. .

4.3.2 Thermal efficiency:

It is the efficiency of conversion of the heat energy produced by the actual combustion ofthe fuel into the power output of the engine. It is the ratio of work done to heat supplied byfuel.

i)Indicated thermal efficiency = Indicated Power/ Heat supplied by fuel


= . .×Where, mf = mass of fuel supplied, Kg/sec and CV = calorific value of fuel, J/kg

ii) Brake thermal efficiency = Brake Power/ Heat supplied by fuel= . .×Also = ×

4.3.3 Relative efficiency:It is the ratio of indicated thermal efficiency of an engine to air standard cycle efficiency=

4.3.4 Air standard efficiency:It is the efficiency of the thermodynamic cycle of the engine.

For petrol engine, = 1 − 1( )For diesel engine, = 1 − 1( ) − 1( − 1)

4.3.5 Volumetric efficiency:It is the ratio of the volume of charge/air actually sucked at atmospheric condition toswept volume of engine. It indicates breathing capacity of the engine.

= ℎ ∨ .4.3.6 Specific output:

The specific output of the engine is defined as the power output per unit area.= . .4.3.7 Specific fuel consumption:

Specific fuel consumption (SFC) is defined as the amount of fuel consumed by an enginefor one unit of power production. SFC is used to express the fuel efficiency of an I.C.engine. = . . ⁄ ℎWhere,mf = Mass of fuel consumed in kg/hr and B.P. = Power produced in KW


Conclusion:

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EXPERIMENT-5

Objective

To understand construction and working of different types of pumps

5.1 Centrifugal PumpsA pump which employs centrifugal force for conveying liquid from one place to another iscalled centrifugal pump. The centrifugal pumps are of roto dynamic type pump.

Types of centrifugal pump(A) According to type of casing,

a. Volute or spiral casing type pumpb. Vortex or whirlpool chamber type pumpc. Diffuser type (casing with guide blades) pump

(B) According to number of stages,a. Single stageb. Multi-stage

Impeller in series

Impeller in parallel

5.2 Rotary pumpsRotary pumps are positive displacement pumps. It consists of fixed casing with a rotor whichmay be in the form of gears, vanes, lobes, screws, cams etc.Centrifugal pump operates on principle of centrifugal action of rotation; the pressure isdeveloped by the centrifugal action of liquid while rotary pumps the pressure is developed bypositive displacement of the liquid.Rotary pump is suitable for pumping viscous fluids like vegetable oil, lubricating oil, alcohol,grease, tar etc.

Types of rotary pumpsThere are main three types of rotary pumps as,

a. Gear pumpb. Vane pumpc. Screw pump


Questions:(1) Explain working of single acting reciprocating pump with neat sketch.(2) Explain working principle of centrifugal pump.(3) Explain main parts of centrifugal pump with sketch.(4) Why priming is required in centrifugal pump? List methods of priming and explain any one

of them.


Conclusion:

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EXPERIMENT – 6

ObjectiveTo understand construction and working of different types of air compressors

6.1 Introduction

“The machines which take in air or any other gas at low pressure and compress it to highpressure are called compressors. Compressors are driven by electric motors, I.C. engines gasturbines.”

6.2 Classification of Compressor1) According to method of compression

Reciprocating compressor Rotary Compressor Centrifugal compressor

(2) According to delivery pressure Low pressure - up to 1.1 bar Medium pressure - 1.1. to 8 bar High pressure – 8 to 10 bar Very high pressure - above 10bar

(3) According to principle of operation Positive displacement Rotodynamic or steady flow compressor

(4) According to the number of stages Single stage compressor Multistage compressor

(5) According to number of cylinder Single cylinder Multi cylinder

(6) According the pressure limit Fans - pressure ratio 1 to 1.1 Blowers - pressure ratio 1.1 to 2.5 Compressor - pressure ratio above 2.5

(7) According to volume of air delivered Low capacity - volume flow rate up to 10 m3/min Medium capacity - volume flow rate 10 m3/min to 300 m3/min High capacity: Volume flow rate above 300 m3/min.

(8) According to fluid to be compressed Air compressor Gas compressor Vapour compressor


Questions:(1) What is air compressor? Give application of compressed air.(2) Explain operation of reciprocating compressor without clearance.(3) Explain concept of multistage reciprocating compressor.(4) Explain Vane compressor with sketch.


Conclusion:

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EXPERIMENT – 7

Objective

Demonstration of domestic refrigerator

7.1 Introduction

Refrigeration can be defined as the method of reducing the temperature of a system belowsurrounding temperature and maintaining it at the lower temperature by continuouslyabstracting the heat from it.Refrigerator is a device which removes heat from cold body and reject to hot body(surrounding) and maintains low temperature for useful purpose. In this device, externalwork is required to convey heat from cold body to hot body.Refrigerant is a heat carrying medium which absorbs heat from space (desired to cool) andrejects heat to outside the refrigerator (in atmosphere).

7.2 Unit of Refrigeration

It is defined as "refrigerating effect produced by melting of 1 ton of ice from and at 0°C in24 hours."

ORAmount of heat required to be removed in order to form one ton of ice in 24 hours fromwater at temperature 0 oC.

7.3 Coefficient of Performance

It is defined as the ratio of refrigerating effect to work required for compressing therefrigerant in the compressor. It is the reciprocal of the efficiency of a heat engine. Thus thevalue of COP is always greater than unity.

7.4 Domestic Refrigerator

The refrigerator is usually specified in terms of volumetric capacity of inside cooling space.Examples…available in capacities of 65 litres, 100 litres, 165 litres, 275Iitres,1000 litres.


Domestic refrigerator


Questions:(1) Give properties of good refrigerant.(2) Explain Vapour compression refrigeration system (VCRS) with P-H diagram.(3) Explain Vapour absorption refrigeration system with diagram.


Conclusion:

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EXPERIMENT-8

Objective

To understand construction, working and applications of different types ofcoupling, clutch and brake.

8.1 IntroductionCoupling and clutches are power transmission elements. It is used for transmitting powerfrom one shaft to the other shaft.A coupling is a device used to connect or couple two shafts while clutch is device whichfacilitate engage and disengage of driving shaft and driven shaft whenever required even itmay rotate.The brake is frictional device whose primary function is to control the motion of machinemember. It is used to bring machine member into rest or slow down.

8.2CouplingsShafts are mostly available up to 7 meter length due to transport difficulty. To get a greaterlength, it is necessary to joint two or more pieces of the shaft using coupling.Purposes of Coupling used are,1. To connect shafts of motor and generator which are manufactured separately and to

provide for disconnection for repairs.2. To reduce the transmission of shock loads from one shaft to another.3. To allow misalignment of the shaft or to introduce mechanical flexibility.4. To introduce protection against overloads.

8.2.1 Types of couplingsCouplings are divided into two main groups as follows,Rigid couplingIt is used to connect two shafts which are perfectly in axial alignment. These couplings donot allow any relative rotation between the two shafts.There are basic three types of rigid coupling as follows,

a. Sleeve or muff couplingb. Clamp or split muff or compression couplingc. Flange coupling: - (1) Unprotected type (2) protected type


8.3 ClutchesThe clutch is a mechanical device used to connect or disconnect from the driving shaft atwheel of the operator while power is transmitted from driving to driven shaft.In automobiles, where vehicle can be stopped for a while or to change the gear, requirementis that the driven shaft should stop but the engine should run naturally under the no loadcondition. This is achieved by using clutch mounted between engine shaft and gearbox shaftand which is operated by a lever.

Classification of Clutcha) Friction Clutch - 1) Single plate clutch 2) Multi plate clutch 3) Cone clutch

4) Centrifugal clutchb) Positive Contact -1) Jaw clutch

8.4 BrakesBrake is a device by means of which an artificial frictional resistance is applied to a movingbody in order to retard or stop the motion of a body. Clutches and brakes work on the sameprinciple of friction but the functional difference between clutch and brake is that the clutchconnects one moving part to another moving part, whereas the brake connects one movingpart to another stationary part.During braking process, the brake absorbs either kinetic energy or potential energy or bothby an object. In automobiles brake absorbs kinetic energy of moving vehicles. In case ofelevators and hoists brake absorb potential energy released by the objects during brakingperiod.The energy absorbed by the brake is converted in the form of heat which is dissipated to thesurrounding air or water which is circulated through the passage in the brake drum.

Classification of brakea) Block or Shoe brake

1) Single block brake 2 ) Double block brakeb) Band brake

1) Simple band brake 2) Differential band brakec) Internal expanding shoe braked) Disc brake


Questions:

(1) Give classification of coupling. Explain Oldham’s coupling with sketch.(2) Explain Single plate clutch (Disc clutch).(3) Explain Internal expanding shoe brake with sketch.(4) Give the difference between clutch and brake.(5) Explain working of Centrifugal clutch.


Conclusion

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EXPERIMENT – 9

Objective

Demonstration of various types of power transmission elements

9.1 Gear drive and friction driveIn case of rope and belt drives we have seen that the velocity ratio transmitted cannot be exactdue to the slip of rope or belt on the pulley. Also due to frictional losses the efficiency of powertransmission in such drives is less. The power may be transmitted from one shaft to another bymeans of mating gears with high transmission efficiency.

In early days, friction discs as shown in figure 10.1 were used for transmitting the power fromone shaft to another shaft. In such a case, the power transmission capacity depends on frictionbetween surfaces of two discs. Therefore, this method is not suitable for transmitting higherpower as slip occurs between the discs.

(a) Frictional disc (b) Gear drive

In order to transmit a definite power from one shaft to another shaft to the projection on one discand recesses on another disc can be made which can mesh with each other. This leads to theformation of teeth on both discs and the discs with teeth on their periphery are known as "Gears".

Advantages

1. It is a positive drive (no slip) i.e. it transmits exact velocity ratio from one shaft toanother shaft.

2. It can transmit very large power.3. High transmission efficiency.4. Requires less space.5. Reliable.


Disadvantages

1. Manufacturing cost of gear is high, since special tools and machinery is required for gearmanufacturing.

2. Maintenance cost of gear drive is also high due to lubrication requirements.3. The error in cutting teeth may cause vibrations and noise during operation.4. It requires precise alignment of shafts.

Spur gear Use

When the axis of two shafts are parallel to each other. These gears have teeth parallel to theaxis of the shaft.

Helical gear In helical gears the teeth are at some angle called helix angle with respect to axis of the shaft. Advantages

1. It runs quieter as compared to spur gears since the contact between teeth is gradual.2. Transmission of load is gradual which results in low impact stresses and reduction in

noise. Thus they are used for high speed transmission.


DisadvantageThey induce axial thrust in one direction on the bearings.

Rack and pinion

It is a special case of spur gear in which one gear is having infinite diameter called "Rack". Use

To transmit the rotary motion into reciprocating motion or vice-versa. Application

Lathe machine, drilling machine and measuring instrument.

Bevel gear UseWhen power is required to be transmitted from one shaft to another shaft which are intersectingto each other then bevel gears are used. Generally, the angle between two shafts is 90⁰.The bevel gears are of two types,

1. Straight bevel gear2. Spiral bevel gear


(1) Straight bevel gears

In straight bevel gears the teeth are formed straight on the cones, and they are parallel to the axisof the gear.

(2) Spiral bevel gearsIn a spiral bevel gear, the teeth are formed at an angle with respect to its axis. The contactbetween two meshing teeth is gradual and smooth from start to end, as in case of helical gears.

Application

Automobile differential

Spiral Gears (Skew gears or Crossed helical gears)


UseTo transmit power from one shaft to another shaft which are non parallel and non intersecting.For low load transmission only since they have point contact between mating teeth.

Worm and worm wheel

UseTo transmit power from one shaft to another shaft which are non intersecting and their axesare normally at right angles to each other.

ApplicationLathe machine to get large speed reduction.

Questions:(1) What is belt drive? Explain types of belt drive with sketch.(2) Give comparison between individual drive and group drive.(3) Give classification of gear and explain any three with sketch.(4) Give comparison between belt drive, chain drive and gear drive.


Conclusion:

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Properties of GasesC1. An air vessel contains 9 kg of air at initial pressure and temperature are 6 bar and

20˚C respectively. After heat supplied pressure of air becomes 12 bar. Take value ofcharacteristic gas constant is 0.287 KJ/kg K and Cv= 0.718 KJ/kg K.Determine 1. Final temperature 2. Heat supplied 3. Work done during process 4.Change in internal energy 5. Change in enthalpy.

ANSWERS: [1] T2 = 586 K [2] Q = 1893.366 KJ [3] W = 0 KJ [4] ∆U = 1893.366 KJ[5] ∆H = 2650.185 KJ

T1. One kg of air at 450 kPa and occupying 0.25m3 is heated at constant volume until thetemperature has risen to 270˚C.Determine (i) initial temperature of air, (ii) final pressure, (iii) heat supplied, (iv)change in internal energy per kg and (v) change in enthalpy during process. Take Cp =1.005 kJ/kg-K and Cv = 0.710 kJ/kg-K.ANSWERS: [1] 338.98 K [2] 6.4 bar [3] 144.852 KJ [4] 144.852 KJ/kg [5] 205.037KJ

H1. In a vessel 9 kg of air is heated with non-flow, constant volume process that pressureof air is increased two times that of the initial value. The initial temperature is 20˚C.Calculate 1. Final temperature 2. Change in internal energy 3. Change in enthalpy and4. Heat transfer 5. Work done Take R=0.287 KJ/kg K. and Cv=0.718 KJ/kg K for air.

ANSWERS: [1] 586 K [2] 1893.366 KJ [3] 26650.185 KJ [4] 1893.366 KJ [5] 0 KJ

C2. A tank filled with 1 kg of gas at init ial pressure and volume are 5 bar and 0.20 m3,respectively. If 47 KJ heat addition to the gas then its temperature reaches 127˚C.Take value of characteristic gas constant is 300 Nm/kg K and Cp= 1.005 KJ/kg K.Determine 1.Work done during process 2. Initial temperature 3. Change in internalenergy 4. Change in enthalpy 5. Final volume.ANSWERS: [1] W = 0 KJ [2] T1 = 333.33 K [3] ∆U = 47.002 KJ [4] ∆H = 67.003 KJ[5] V2 = 0.20 m3

T2. A cylinder vessel of 1 m diameter and 4 m length has hydrogen has at pressure of 100Kpa and 27˚CDetermine amount of heat to be supplied so as to increased pressure to 125 Kpa. Forhydrogen Cp= 14.3005 KJ/kg K and Cv= 10.183 KJ/kg K.ANSWER: Q = 194.215 KJ

H2. A tank contains 3m3 of air at 25 bar absolute pressure. This air is cooled until itspressure and temperature decrease to 15 bar and 21˚C respectively.

Determine change in internal energy, change in enthalpy and heat transfer. Take Cp =1.005 kJ/kg-K and Cv = 0.718 kJ/kg-K for air.ANSWERS: [1] -7505.024 KJ [2] -10504.94 KJ [3] -7505.024 KJ

C3. 5 kg of gas contains in piston cylinder assembly with initial volume, pressure andtemperature are 0.5 m3, 8 bar and 105˚C respectively. If heating of gas at constantpressure then its temperature becomes 270˚C. Assume value of Cp= 1.005 KJ/kg K andCv= 0.793 KJ/kg K.Determine 1.Heat supplied during process 2. Final volume 3. Work done 4. Change ininternal energy 5. Change in enthalpy 6. Final pressure.ANSWERS: [1] Q = 829.125 KJ [2] V2 = 0.718 m3 [3] W = 174.400 KJ [4] ∆U =654.225 KJ [5] P2= 8 bar

T3. The cylinder contains gas with initial pressure, volume, and temperatures are 0.7 Mpa,0.14 m3, and 15.5˚C respectively. The volume of gas increases up to 0.5 m3 after heatadded at constant pressure. Assume value of characteristic gas constant is 287 J/kg K andCv= 0.713 KJ/kg K.Determine 1.Final temperature, Final pressure 2. Heat supplied during process 3.Work done 4. Change in enthalpy.

ANSWERS: [1] T2 = 1033.36 K, P2 = 700 KN/m2 [2] Q = 881.54 KJ [3] W = 252 KJ[4] ∆H = 881.54 KJ

H3. The gas whose pressure, volume, and temperatures are 2.75 bar, 0.09 m3, and 185˚Crespectively has the state changed at constant pressure until its temperature becomes15˚C. Take R= 0.29 KJ/kgK and Cp= 1.005 KJ/kg K.Calculate 1. Heat transferred 2. Work done during the process.ANSWERS:[1] Q = -31.829 KJ [2] w = -9.1867 KJ

C4. In an air compressor air enters with initial volume, pressure and temperatures are0.625 m3, 0.3 bar and 95˚C respectively. If compression occurs isothermally thenpressure after compression raises up to 0.1 MPa. Assume value of characteristic gasconstant is 287 J/kg K.Determine 1.Mass of air 2. Final temperature 3. Heat supplied during process 4. Workdone 5. Change in internal energy 6. Change in enthalpy.

ANSWERS: [1] m = 0.1775 kg [2] T2 = 368 K [3] Q = -22.574 KJ [4] W = -22.574 KJ[5] ∆U = 0 KJ [6] ∆H = 0 KJ

T4. 0.45 kg of air is sucks in an air compressor with initial pressure and temperature are20 kN/m2 and 30˚C respectively. If compression is isothermal then volume aftercompression reduces up to 0.06 m3. Assume value of characteristic gas constant is287 J/kg K.determine 1.Final temperature 2. Init ial volume 3. Work done 4. Heatsupplied during process 5. Change in enthalpy and 6. Change in internal energy.

ANSWERS: [1] T2 = 303 K [2] V1 = 1.957 m3 [3] W = -136.36 KJ [4] Q = -136.36 KJ[5] ∆U = 0 KJ [6] ∆H = 0 KJ

H4. In an air compressor air enters at 1.013 bar and 27˚C having volume 5 m3/kg and it iscompressed to 12 bar isothermally. Determine 1. Work done 2. Heat transfer and 3.Change in internal energy.ANSWERS: [1] W = -1252.063 KJ [2] -1252.063 KJ [3] ∆U = 0 KJ

C5. Determine the work done in compressing one kg of air from a volume of 0.15 m3at apressure of 1 bar to a volume of 0.05 m3, when the compression is (i) isothermal and(ii) adiabatic, take γ = 1.4. Also comment on your answer.

ANSWERS: [1] W = -16.479 KJ [2] w = -20.687 KJ

T5. One kg of gas at 100 KN/m2and 17˚C is compressed isothermally to a pressure of2500 KN/m2 in a cylinder. The characteristic equation of gas is given by the equationPV= 260T/kg where T is in degree Kelvin. Find out 1. Final temperature 2. Finalvolume 3. Compression ratio 4. Change in enthalpy 5. Work done on the gas.

ANSWERS: [1] T2 = 290 K [2] V2 = 0.03016 m3 [3] r = 25 [4] 0 KJ [5] -242.703KJ

H5. 0.45 kg of air at a pressure of 0.2 bar and 30°C is compressed is isothermally until itsvolume is 0.06 m3. Determine the final temperature, work done & heat transferredduring process, ∆H and ∆U. Take R=287 J/Kg K.

ANSWERS: [1] 303 K [2] -136.360 KJ [3] -136.360 KJ [4] 0 KJ [5] 0 KJ

Properties of Steam

C1. Following data to be observed during test on throttling CalorimeterPressure in main before throttling = 13 barPressure after throttling = 1 barTemperature of steam after throttling = 135˚CSpecific heat of steam = 2.1 kJ/kg KDetermine dryness fraction for throttling calorimeter.ANSWER: X = 0.9818

T1. On a test with throttling calorimeter, to determine dryness fraction of steam, a sampleis taken from main pipe at 11 bar pressure and temperature after throttling are 1 barand 130°C respectively. Calculate dryness fraction of steam sample. Take Cp= 2.1kJ/kg K.ANSWER: X = 0.9797

H1. Following data to be observed during test on throttling calorimeterPressure in main before throttling = 6 barPressure after throttling = 0.1 MPaTemperature of steam after throttling = 122˚CSpecific heat of steam = 2.1 kJ/kg KDetermine dryness fraction for throttling calorimeter.ANSWER: X = 0.9841

C2. Combined separating and throttling calorimeter is used to find out dryness fraction ofthe steam.Following readings were taken,Main Pressure = 12 bar abs.Mass of water collected in separating calorimeter = 2 kgMass of steam condensed in throttling calorimeter = 20 kgTemperature of steam after throttling = 110˚CPressure after throttling = 1 bar abs.Assume Cp of steam = 2.1 kJ/kg KCalculate dryness fraction of steam.ANSWER: X = 0.8698

T2. The following information is available from test of a combined separating andthrottling calorimeter.Pressure of steam in a steam main = 9 barPressure after throttling = 1 barTemperature after throttling = 115˚CMass of steam condensed after throttling = 1.8 kgMass of water collected in the separator = 0.2 kgCalculate dryness fraction of steam in the mainANSWER: X = 0.8713

H2. Find the quality of steam supplied in a combined separating and throttling calorimeteras per below data available.Initial pressure = 10 barFinal pressure = 1 barWater separated = 1.5 kgSteam discharged from throttling calorimeter = 20 kgTemperature of steam after throttling = 120°CANSWER: X = 0.9033

C3. Following data to be monitoring during test on combined separating throttlingCalorimeterPressure in main before throttling = 8 barTemperature of steam after throttling = 110˚CBarometer reading = 754 mm of HgManometer reading = 81.5 mm of HgMass of steam separated = 60 kgMass of moisture (water) separated = 1.5 kgSpecific heat of steam = 2.1 kJ/kg KDetermine dryness fraction for combined separating throttling calorimeter.ANSWER: X = 0.9412

T3. Following data obtained from test on combined separating and throttling calorimeter.Pressure of steam in pipe = 7.5 barTemperature of steam in throttling calorimeter = 110°CPressure of steam in throttling calorimeter = 81.5 mm HgBarometer reading = 754 mm of HgSteam entering in to separating calorimeter = 63 kgWater collecting in separating calorimeter = 1.5 kgCalculate dryness fraction of steam entering the calorimeter.ANSWER: X = 0.9436

H3. Following data to be monitoring during test on combined separating throttlingCalorimeterMass of water separated = 3.5 kgMass of steam separated = 19 kgTemperature of steam after throttling = 107˚CPressure in main before throttling = 15 barBarometer reading = 760 mm of HgManometer reading = 5 mm of HgDetermine dryness fraction for combined separating throttling calorimeter.ANSWER: X = 0.8013

C4. Determine dryness fraction of steam supplied to a separating throttling calorimeter.Water separated in separating calorimeter = 0.45 kgSteam discharged from throttling calorimeter = 7 kgSteam pressure in a main pipe = 1.2 MPaBarometer reading = 760 mm of Hg

Manometer reading = 180 mm of HgTemperature of steam after throttling = 140˚CTake Cps of steam = 2.1 kJ/kg KANSWER: X = 0.9270

T4. Following data obtained during test on combined separating and throttlingcalorimeter.Water separated = 2 kgSteam discharged from throttling calorimeter = 20.5 kgTemperature of steam after throttling = 110°CInitial pressure = 12 barBarometer reading = 760 mm of HgFinal pressure = 5 mm of HgDetermine the quality of steam supplied.Take Cp of superheated steam as 2.2 kJ/kg K.ANSWER: X = 0.8721

H4. The following data were obtained with a separating and throttling calorimeter.Pressure in pipe line = 1.6 MPa Conditionafter throttling = 0.1 MPa, 120°CMoisture collected in separating calorimeter during 5 minutes = 0.18 litre at 70°CSteam condensed after throttling during 5 minutes = 4 kgDetermine the quality of steam in the pipeline.ANSWER: X = 0.9213

C5. Following data available for 5 kg of steam at different condition.Determine 1. Enthalpy and internal energy when steam has dryness fraction 0.9 at 0.8bar 2. Enthalpy and internal energy when steam is dry at 0.8 bar and 3. Enthalpy andinternal energy when steam is superheated at 300˚C at 20 bar.ANSWERS: [1] Hwet = 12191.95 kJ, Uwet = 11440.63 kJ [2] Hdry = 13329 kJ, Udry =12494.24 kJ [3] Hsup = 14905.8 kJ, Usup = 13730.6 kJ

T5. Determine the enthalpy and internal energy of 1 kg of steam at a pressure 10bar(abs.),(i) When dryness fraction of steam is 0.85 (ii) When steam is dry andsaturated (iii) When the steam is superheated to 300˚C. Neglect the volume of waterand take the specific heat of superheated steam as 2.1 kJ/kg K.ANSWERS: [1] Hwet = 2474.16 kJ, Uwet = 2309.06 kJ [2] Hdry = 2776.2 KJ, Udry =2581.9 kJ [3] Hsup = 3028.41 kJ, Usup = 2782.61 kJ

H5. One kg of steam at pressure of 15 bar with dryness fraction of 0.06. Determineenthalpy, specific volume and internal energy of steam.

ANSWERS: [1] H = 961.318 kJ [2] v = 0.008984 m3/kg [3] U = 947.842 kJ

Heat EngineC1. An engine working on a Carno t cycle with wo rking flu id as a gas has the max imu m

pressure and temperatures of the cycle as 30 bar and 550k respectively. the expansion andcompression ratios for the isothermal and adiabatic pro cesses are 4 and 6 respectively. Themass of gas in the system 1 is kg. Calculate the properties o f gas at salient po ints, the workdone during the cycle and thermal efficiency. Take γ=1.4 R=0.3 KJ/kgK.

ANSWERS: [V1 = 0.055 m3 V2 = 0.22 m3 V3 = 1.32 m3 V4 = 0.33 m3 T1= 550 K T2=550 K T3= 268.55 K T4= 268.55 K ή = 51.2%]

T1. The Initial pressure and temperature of the air taken through a Carnot cycle are 15 bar and270 ˚C resp ectively. F rom the init ial conditions, the air is expanded isothermally to threetimes its initial volume then the cycle is completed by isothermal compression and adiabaticcomp ression. Take V3=6V1. Determine 1) the pressure, volume and temperature at eachcorner of the cycle. 2) the thermal efficiency of the cycle 3) the work done per cycle.

ANSWERS: a) V1 = 0.105 m3 V2 = 0.315 m3 V3 = 0.63 m3 V4 = 0.21 m3 T1= 543K T2=543 K T3= 411.52 K T4= 411.52 K P1 = 15 bar P2 = 5 bar P3 = 1.89 bar P4 = 5.67 bar b) ή =24.21% c) W.D =41.9 KJ]

H1. A hot air engine works on Carnot cycle with thermal efficiency of 70%.if final temp of airis 20 ⁰C. Determine the initial temp.

ANSWERS: [T1= 703.667 oC]

C2. An engine is work ing on ideal Otto cycle. The temp o f the beginning and the endofcompression is 60˚C and 450 ˚C .Determine the air standard efficiency and compressionratio.ANSWERS: [r = 6.94 η = 53.92%]

T2. In air standard Otto C ycle the Maximum and Minimum temperatures are 1673 K and 288K.The heat supplied per kg of air is 800 KJ. Calculate (i) The Compression Ratio. (ii) Efficiency(iii) Max & Min Pressures. Take Cv = 0.718 kJ/kg K and γ = 1.4 for air. ANSWERS: [1)r=5.244, 2) η=48.46%]

H2. Determine the Air Standard Efficiency of an Otto cycle from the Following

Bore of the Cylinder is 14cm, Stroke Length 13 cm, Clearance Volume 290 cm3

ANSWERS: [r = 7.9 η = 56.25%]

C3. In an Otto cycle the co mpressio n ratio is 8. The temperatures at the beg inn ing ofcompression and at the end of heat supply are 3 10 K and 1600 K respectively. Assumeγ=1.4 and Cv = 0.717 kJ/Kg K. F ind (i) Heat S upplied (ii) Efficiency of the cycle.ANSWERS: [1) Q = 636.56 kJ/Kg, 2) η = 56.46%]

T3. An engine works o n the constant vo lume cycle. It has a cylinder bore of 90 mm and piston stroke of 100mm. the clearance vo lume of the engine is 0.06 litre. The actualthermal efficiency of the engine is 22%. Determine the relative efficiency o f the engine.Take γ=1.4.

ANSWERS: [η=35.21%]

H3. In an engine working on Otto cycle a ir has a pressure of 1 bar and temp 303 k at the entry.air is compressed with a compression ratio of 6.the heat is added at constant volume untilthe temp rises 1773 k. Determine i) air standard efficiency ii)pressure and temp at the end ofcompression iii) heat supplied.

ANSWERS: [i) η=51.16% ii) P2 = 12.286 bar T2= 620.44 K iii) Q= 827.54 KJ/Kg]

C4. An oil engine working on diesel cycle has cylinder bore of 190 mm and piston stroke of 230

mm. The clearance volume is 290 cm3.the fuel injection takes place at co nstant pressurefor 6% of the stroke. Determine the air standard efficiency. Also calculate the percentage ofloss of efficiency if fuel cut off is delayed from 6% to 11% of stroke with same compressionratio.

ANSWERS: [1) η = 65.46% 2) Loss in efficienc= 6.095T4. The compression ratio of an oil engine working on Diesel Cycle is 15. C ut off takes place at

12 % of the working stroke. The air is drawn in to cylinder at 100 kPa and 27°C. AssumeCp=1.006 kJ/kg K and Cv =0.717 kJ/kg K. Calculate:(i) Temperature at the end of compression (ii) Pressure at the end of compression (iii) Air std. efficiency of the cycle.

ANSWERS: [ 1) T2=886.25 2) P2=44.31 bar 3) η = 57.18% ]

H4. In an ideal diesel cycle, the temperatures at the beginning and at the end of compression are57˚C and 603 ˚C respectively. The temperature at the begining and at the end of expansion is1950 ˚C and 870˚C respectively. Determine the ideal efficiency of the cycle. If the pressure atthe beginning is 1 bar .calculate maximum pressure in the cycle. ANSWERS: [ I) η = 56.89%II) P2=30.47 bar]

C5. An engine operating a diesel cycle has maximum pressure and temperature of 45 bars and1500˚C. Pressure and temperature at the beginning of compression are 1 bar and 27 ˚C. Determine airstandard efficiency of the cycle. Take γ=1.4

ANSWERS: [η = 60.58%]

T5. The compression ratio of an oil engine working on Diesel Cycle is 15. Cut off takes place at 6% of the working stroke, heat add it io n at constant pressure. Determine air standardefficiency of the cycle. Take γ=1.4 June 06 6 MarksANSWERS: [η = 61.19%]

H5. An oil engine works on diesel cycle with temp of 25˚C at the starting of compression if the ratioof adiabatic compression is 16 and that of adiabatic expansion I 9. Find the efficiency of cycletake γ=1.4 for air ANSWERS: [η = 62.449%]

I. C. EnginesC1. Following readings taken during test on single cylinder four stroke Petrol engine,

Cylinder bore = 25cmStroke length = 400 mmMean effective pressure = 6.5 barEngine speed = 250 rpmNet load on brake drum = 1080 NEffective diameter of drum = 1.5 mFuel consumption = 10 kg/hrCalorific value = 44300 kJ/kgClearance volume = 1.196 X 10-3m3

Determine 1.Indicated power 2.Brake power 3.Friction power 4.Mechanical efficiency5.Indicated thermal efficiency 6.Brake thermal efficiency 7.Air standardefficiency 8.Relative efficiency 9.BSFC and 10. Brake mean effective pressure in bar.Take γ=1.4.ANSWERS: [1] I.P = 26.59kW [2] B.P = 21.206 kW [3] F.P = 5.384 kW [4] ηm= 79.75% [5] ηith= 21.61% [6] ηbth= 17.23 % [7]ηair= 61.67 % [8]ηrel=35.04 % [9] BSFC= kg/kW hr[10] Pbm= 16.286 bar

T1. Following results refers to a test on I.C engine,Indicated Power = 42 KWFriction Power = 7 KWEngine Speed = 1800 rpmSpecific fuel consumption per b.p = 0.30 kg/KwhCaloric fuel value = 43000 KJ/KgCalculate :- 1) Mechanical efficiency 2) Brake thermal efficiency 3) Indicated thermalefficiencyANSWERS: [1]ηm= 83.33 % [2] 27.91%bth [3] ηith= 33.49%

H1. Following readings taken during test of four stroke single cylinder Petrol engine,Load on the brake Drum = 50 kgSpring balance reading = 7 kgFuel consumption = 4 kg/hrDiameter of brake drum = 1250 mmEngine speed = 450 rpmCalorific valueof the fuel = 43000 kJ/kgCalculate 1. Indicated thermal efficiency 2. Brake thermal efficiency.Assumemechanical efficiency as 70 %.ANSWERS: [1]ηith=37.14 % [2]ηbth= 26 %

C2. Following readings taken during test on single cylinder four stroke Petrol engine,Stoke length = 40 cmCylinder bore = 25 cmMean effective pressure = 4 barEngine speed = 1400 rpmFriction power = 10 kWFuel consumption = 20 litres/hrCalorific value = 45000 kJ/kgSpecific gravity = 0.8

Determine: 1. indicated thermal efficiency 2.brake thermal efficiency.ANSWERS: [1]ηith= 45.85% [2]ηbth=40.85%

T2. Following observations were recorded during test ona single cylinder oil engine,Bore = 300 mmStoke length = 450 mmEngine speed = 300 rpmI.M.E.P = 6 barNet brake load = 1.5 kNBrake Drum diameter = 1.8 mBrake Rope diameter = 2 cmCalculate 1. Indicated Power2. Brake power and 3. Mechanical efficiency.ANSWERS: [1] I.P= 47.713 kW [2] B.P= 42.883 kW [3]ηm= 89.88%

H2. During testing of on single cylinder two stroke petrol engine following data is obtained.Brake Torque = 640 N mCylinder diameter = 21 cmEngine speed = 350 rpmStoke length = 28 cmM.E.P = 5.6 barOil consumption = 8.16 kg/hrCalorific value = 42705 kJ/kgDetermine 1. Mechanical efficiency 2. Brake thermal efficiency and 3. Brake specificfuel consumption.ANSWERS: [1]ηm= 74.04 % [2]ηbth= 24.23 % [3] BSFC= 0.348 kg/kWh

C3. Following readings taken during test on single cylinder four stroke Diesel engine,Load on brake drum = 55 kgSpring reading = 9 kgDiameter of drum = 1.4 mDiameter of rope = 0.8 mFuel consumption = 3.8 kg/hrCalorific value = 42500 kJ/kgEngine speed = 600 rpmMechanical efficiency = 83 %Compression ratio = 7Stroke to bore ratio = 1.25Determine 1.Brake thermal efficiency 2.Indicated thermal efficiency 3.Air standardefficiency.ANSWERS: [1]ηbth= 69.47 %[2] ηith= 83.70%[3] ηair= 83.70%

T3. Following readings were taken during test on a single cylinder four stroke oil engine,Cylinder diameter = 270 mmStoke length = 380 mmMean effective pressure = 6 barEngine speed = 250 rpmNet load on brake = 1000 NEffective mean diameter of brake = 1.5 mFuel used = 10 kg/hr

C.V of fuel = 44400 kJ/kgCalculate 1. Brake power 2. Indicated Power 3. Mechanical efficiency and 4. Indicatedthermal efficiency.ANSWERS: [1] B.P= 19.635 KW [2] I.P= 27.196kW[3]ηm= 72.20 % [4]ηith= 22.05%

H3. Following results refers to a test on C.I engine,

Indicated Power = 37 kW

Frictional Power = 6 kWBrake Specific fuel consumption = 0.28 kg/kWhCalorific value of fuel = 44300 kJ/kgCalculate 1. Mechanical efficiency , 2. Overall efficiency and, 3. Indicated thermalefficiency

ANSWERS: [1]ηm= 83.78 % [2]ηo= 29.02 % [3] ηith=34.64 %

C4. Following readings taken during test on two cylinder four stroke Petrol engine,Swept volume = 1.3 X 10-3 m3

Brake power = 110 kWEngine speed = 1000 rpmFuel consumption = 2.8 kg/hrMean effective pressure = 900 kN/m2

Calorific value = 42800 kJ/kgPiston speed = 5 m/sIf clearance volume is 10 % of swept volume. Take γ = 1.4. Determine 1.Stoke lengthand diameter 3.Indicated thermal efficiency and 3.Relative efficiency.ANSWERS:[1]l = 0.15 m, d = 0.105 m [2] ηith= 58.58 % [3] ηrel= 94.98%

T4. A six cylinder 4 stroke IC engine is to develop 89.5 kW indicated power at 800 rpm. Thestroke to bore ratio is 1.25:1. Assuming mechanical efficiency of 80 % and brake meaneffective pressure of 5 bar. Determine diameter and stroke length of the engine.ANSWERS:[1]d = 0.154m [2] l = 0.193 m

H4. During test on a single cylinder four stroke engine having compression ratio of 6,following data is recorded.

Bore = 10 cmStoke length = 12.5 cmIMEP = 2.6 barDead load on Dynamometer = 60 NSpring balance reading = 19 NEffective radius of flywheel = 40 cmFuel consumption = 1 kg/hrC.V of fuel = 42000 kJ/kgEngine speed = 2000 rpmDetermine its, 1. Indicated Power2. Brake power 3. Mechanical efficiency 4. Air standardefficiency and 5. Relative efficiency.ANSWERS: [1] I.P = 4.254 kW [2] B.P= 3.435 kW [3]ηm= 80.75% [4]ηair= 51.16 %[5]ηrel=71.27 %

C5. Following readings taken during test on six cylinder four stroke Petrol engine,

Brake Power = 300 kWEngine speed = 2500 rpmStroke to bore ratio = 1.25Mean effective pressure = 0.9 MPaMechanical efficiency = 80 %Indicated thermal efficiency = 30 %Calorific value = 41900 kJ/kgDetermine stroke length, diameter and fuel consumption.ANSWERS: [1] d = 0.150 m [2] l = 0.187 m [3] mf= 108 kg/hr

T5. Following readings were taken during test on single cylinder four stroke oil engine,Cylinder diameter = 250 mmStoke length = 400 mmMean effective pressure = 6.5 barEngine speed = 250 rpmNet load on brake = 1080 NEffective diameter of brake = 1.5 mFuel used per hour = 10 kgCalorific value of fuel = 44300 kJ/kgCalculate 1. Indicated Power 2. Brake power 3. Mechanical efficiency 4. Indicatedthermal efficiency.ANSWERS: [1] I.P= 26.589 kW [2] B.P= 21.206 kW [3]ηm= 79.75 %[4]ηith= 21.61 %

H5. A four cylinder four stroke petrol engine develops 200 kW brake power at 2500 rpm.Stroke to bore ratio 1.2. If mean effective pressure is 10 bar and mechanical efficiency is81%. Calculate bore and stroke of the engine. Also calculate indicated thermal efficiency andbrake thermal efficiency if 65 kg/hr of petrol is consumed having calorific value of 42000 kJ/kg.ANSWERS: [1] d = 0.146 m, l = 0.175 m [2]ηith=32.56 %

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