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GUJARAT TECHNOLOGICAL UNIVERSITY

ELEMENTS OF MECHANICAL ENGINEERING

SUBJECT CODE: 2110006

B.E. 1st YEAR

Type of course: Engineering Science

Prerequisite: Zeal to learn the subject

Rationale: Understanding of basic principles of Mechanical Engineering is required in various field

of engineering.

Teaching and Examination Scheme:

Teaching Scheme Credits Examination Marks Total

Marks L T P C Theory Marks Practical Marks

ESE

(E)

PA

(M)

ESE

Viva (V)

PA

(I)

4 0 2 6 70 30* 30 20** 150 L- Lectures; T- Tutorial/Teacher Guided Student Activity; P- Practical; C- Credit; ESE- End Semester Examination;

PA- Progressive Assessment

Content:

Sr # Topic Teaching

Hrs.

Module

Weightage

1

Introduction:Prime movers and its types, Concept of Force,

Pressure, Energy, Work, Power, System, Heat, Temperature,

Specific heat capacity, Change of state, Path, Process, Cycle,

Internal energy, Enthalpy, Statements of Zeroth Law and First

law

4

25% 2

Energy: Introduction and applications of Energy sources like

Fossil fuels, Nuclear fuels, Hydel, Solar, wind, and bio-fuels,

Environmental issues like Global warming and Ozone depletion

3

3

Properties of gases:Gas laws, Boyle's law, Charle's law,

Combined gas law, Gas constant, Relation between Cp and Cv,

Various non flow processes like constant volume process,

constant pressure process, Isothermal process, Adiabatic process,

Poly-tropic process

5

4

Properties of Steam:Steam formation, Types of Steam,

Enthalpy, Specific volume, Internal energy and dryness fraction

of steam, use of Steam tables, steam calorimeters

6

30% 5

Heat Engines:Heat Engine cycle and Heat Engine, working

substances, Classification of heat engines, Description and

thermal efficiency of Carnot; Rankine; Otto cycle and Diesel

cycles

5

6

Steam Boilers:Introduction, Classification, Cochran, Lancashire

and Babcock and Wilcox boiler, Functioning of different

mountings and accessories

-

7 Internal Combustion Engines:Introduction, Classification, 4 20%

Engine details, four-stroke/ two-stroke cycle Petrol/Diesel

engines, Indicated power, Brake Power, Efficiencies

8 Pumps: Types and operation of Reciprocating, Rotary and

Centrifugal pumps, Priming 3

9 Air Compressors:Types and operation of Reciprocating and

Rotary air compressors, significance of Multistaging 3

10

Refrigeration & Air Conditioning:Refrigerant, Vapor

compression refrigeration system, vapor absorption refrigeration

system, Domestic Refrigerator, Window and split air conditioners

4

25%

11

Couplings, Clutches and Brakes: Construction and applications

of Couplings (Box; Flange; Pin type flexible; Universal and

Oldham), Clutches (Disc and Centrifugal), and Brakes (Block;

Shoe; Band and Disc)

3

12 Transmission of Motion and Power: Shaft and axle, Belt drive,

Chain drive, Friction drive, Gear drive 4

13

Engineering Materials:Types and applications of Ferrous &

Nonferrous metals, Timber, Abrasive material, silica, ceramics,

glass, graphite, diamond, plastic and polymer

4

Note: Topic No. 6 of the above syllabus to be covered in Practical Hours.

Reference Books:

1. Elements of Mechanical Engineering by N M Bhatt and J R Mehta, Mahajan Publishing House

2. Basic Mechanical Engineering by Pravin Kumar, Pearson

3. Fundamental of Mechanical Engineering by G.S. Sawhney, PHI Publication New Delhi

4. Elements of Mechanical Engineering by Sadhu Singh S. Chand Publication

5. Introduction to Engineering Materials by B.K. Agrawal Tata Mcgraw Hill Publication, New

Delhi

Course Outcome:

After learning the course the students should be able to

1. To understand the fundamentals of mechanical systems

2. To understand and appreciate significance of mechanical engineering in different fields of

engineering

List of Experiments:

1. To understand construction and working of various types of boilers.

2. To understand construction and working of different boiler mountings and accessories.

3. To determine brake thermal efficiency of an I. C. Engine.

4. To understand construction and working of different types of air compressors.

5. To demonstrate vapor compression refrigeration cycle of domestic refrigerator OR window air

conditioner OR split air conditioner.

Open Ended Problems: Apart from above experiments a group of students has to undertake one

open ended problem/design problem. Few examples of the same are given below.

1. Develop a prototype of gear train/drive for certain velocity ratios.

2. Develop a small boiler with different mountings.

3. Develop a hot air engine

Major Equipments: Models of Cochran, Lancashire and Babcock and Wilcox boilers, models of

various mountings and accessories, Models of various types of IC engines, Single cylinder two

stroke /four stroke petrol/ diesel engine, models of pumps, compressors, refrigerator/air conditioner,

models of various types of brakes, coupling, clutches, drives

List of Open Source Software/learning website: http://nptel.iitm.ac.in, http://vlab.co.in/

*PA (M): 10 marks for Active Learning Assignments, 20 marks for other methods of PA

ACTIVE LEARNING ASSIGNMENTS: Preparation of power-point slides, which include videos,

animations, pictures, graphics for better understanding theory and practical work – The faculty will allocate

chapters/ parts of chapters to groups of students so that the entire syllabus of Elements of Mechanical

Engineering is covered. The power-point slides should be put up on the web-site of the College/ Institute,

along with the names of the students of the group, the name of the faculty, Department and College on the

first slide. The best three works should be sent to [email protected].

** PA (I): 10 marks for a case study of Systems, 10 marks for other methods of PA.

The case study of Systems: The case study should be of a working EE system, which shows the working of

the concepts, included in the Syllabus.

#ESE Pr (V):10 marks for Open Ended Problems, 20 marks for VIVA.

Note: Passing marks for PA (M) will be 12 out of 30.

Passing marks for ESE Pract(V) will be 15 out of 30.

Passing marks for PA (I) will be 10 out of 20

Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER–1/2 (NEW) EXAMINATION – WINTER 2017

Subject Code: 2110006 Date: 02/01/2018 Subject Name: Elements of Mechanical Engineering Time: 10:30 AM TO 01:00 PM Total Marks: 70 Instructions:

1. Question No. 1 is compulsory. Attempt any four out of remaining Six questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

4. Use of steam tables is permitted.

Q.1 Objective Question (MCQ) Mark

(a) 07

1. Bio fuels can be produced from

(a) Biomass (b) agricultural waste (c) Municipal garbage (d) all of

the above.

2. Which of the following is high grade energy

(a) work (b) heat (c) chemical energy (d) none of the above

3. In a compressor, the work done is 200kJ and heat rejected to the

surrounding is 50kJ. The change in internal energy is

(a) 150kJ (b) 250kJ (c) 4kJ (d) 10000kJ

4. Air is assumed to be

(a) Ideal gas (b) Real gas (c) Condensed gas (d) none of the above.

5. Dryness fraction of fully wet steam is

(a) 0 (b) 1 (c) 0.5 (d) none of the above

6. Air standard Otto cycle is also called

(a) Constant volume cycle (b) constant pressure cycle (c) dual

pressure cycle (d) isothermal cycle

7. Which of the following is boiler mounting

(a) Super heater (b) Air preheater (c) Economizer (d) Blow off cock

(b) 07

1. In a two stroke engine ports are operated by movement of

(a) Crank (b) Piston (c) Connecting rod (d) Piston pin

2. The process of filling liquid in casing of pump is

(a) charging (b) pre-starting (c) idling (d) Priming

3. The unit of specific fuel consumption is

(a) Kg/sec (b) kg/kWh (c) kg/kW (d) none of the above

4. The compressor used in aircrafts is

(a) Axial flow (b) Roots blower (c) Vane blower (d) Reciprocating

compressor

5. Refrigerant used in domestic refrigerators is generally

(a) R134a (b) carbon dioxide (c) oxygen (d) ammonia

6. The size of gear is specified by

(a) Number of teeth (b) pitch circle diameter (c) pressure angle (d)

none of the above

7. Mild steel contains % of carbon

(a) 0 to 0.5 (b) 0.5 to 1 (c) 1 to 2 (d) 2 to 4.

Q.2 (a) Explain the following: Global Warming, Ozone depletion. 03

(b)

(c)

An engine operating on the ideal diesel cycle has a maximum pressure

of 45 bar and a maximum temperature of 1500°C. The pressure and

temperature of air at the beginning of compression stroke are 1 bar and

27°C resply. Find the air standard efficiency of the cycle. Assume γ=1.4

What is adiabatic process? Prove with usual notations the law of

governing adiabatic process as PVγ = Constant.

04

07

Q.3 (a) With usual notations derive expression for air standard efficiency of

Otto cycle. 03

(b)

(c)

Draw neat sketches of following: Cochran boiler, bourden pressure

gauge.

During a test on a single cylinder four stroke engine having compression

ratio of 6, the following data is recorded, Bore=10 cm, stroke =12.5 cm,

IMEP =2.6 bar, dead load on dynamometer =60 N spring balance

reading =19N, Effective radius of fly wheel =40 cm, fuel consumption

=1 kg/hr calorific value of fuel is 42000 K J/ Kg speed=2000rpm.

Determine indicated power, brake power, mechanical efficiency,

overall efficiency, air standard efficiency and relative efficiency.

04

07

Q.4 (a) List advantages and disadvantages of two stroke engines over four

stroke engines 03

(b)

(c)

Write short note on : Gear Pump

With neat sketch explain construction and working of Super heater. 04

07

Q.5 (a) Differentiate between reciprocating pump and centrifugal pump. 03

(b)

(c)

Define following terms: swept volume, clearance volume, stroke length,

compression ratio.

Calculate mass of 0.2m3 of steam at 10 bar pressure having dryness

fraction of 0.7. Also calculate enthalpy, internal energy, and external

work during evaporation of 2 m3 of steam.

04

07

Q.6 (a) List properties and application of Titanium and its alloys. 03

(b)

(c)

Define following terms: Ductility, Resilience, Hardness, and Elasticity.

Compare belt drive, chain drive and gear drive. 04

07

Q.7 (a) With neat sketch explain construction and working of cone clutch. 03

(b)

(c)

Draw neat and labeled sketches only of following: Protected flange

coupling, internal expanding shoe brake, Band brake.

With neat sketch explain construction and working of split air

conditioner.

04

07

***********


GUJARAT TECHNOLOGICAL UNIVERSITY BE- SEMESTER 1st / 2nd EXAMINATION (NEW SYLLABUS) – SUMMER - 2017

Subject Code: 2110006 Date:31/05/2017

Subject Name: Elements of Mechanical Engineering

Time: 2:30 PM to 05:00 PM Total Marks: 70 Instructions:




Q.1 Objective Question (MCQ) MARKS

Attribute

(a) 07

1. In an isolated system, what transfer?

(a) mass (b) energy (c) both mass and energy (d) neither mass nor energy

2. Which of the following is a path function?

(a) heat (b) temperature (c) pressure (d) volume

3. Which has the highest calorific value?

(a) Petrol (b) Diesel oil (c) Alcohol (d) Benzene

4. Choose the incorrect relationship.

(a) CP + CV = R (b) CP - CV = R (c) = CP / CV (d) CV = R/( -1)

5. Steam coming out of the whistle of pressure cooker is

(a) Dry and saturated vapour (b) Wet vapour

(c) Superheated vapour (d) Ideal gas

6. Superheating of steam is done at constant

(a) pressure (b) volume (c) temperature (d) enthalpy

7. The Otto cycle is also known as

(a) constant pressure cycle (b) constant volume cycle

(c) constant temperature cycle (d) constant enthalpy cycle

(b) 07

1. When heat is added to the water and if its temperature does not change, the

heat added is called

(a) latent heat (b) isothermal heat

(c) sensible heat (d) constant pressure heat

2. Which one of the following is vertical boiler?

(a) Lancashire (b) Cochran (c) Cornish (d) Locomotive

3. Petrol engine work on ________system.

(a) either spark or compression ignition (b) spark ignition

(c) compression ignition (d) all of the above

4. Scroll compressor is a ______________compressor.

(a) reciprocating (b) rotary

(c) dynamic (d) radial

5. Pump cannot be driven by

(a) electric motor (b) I.C. Engine

(c) steam turbine (d) compressor

6. Performance parameter for refrigeration system is known as

(a) efficiency (b) COP

(c) effectiveness (d) energy ratio

7. In VCR cycle, refrigeration effect is produced by

(a) compressor (b) condenser

(c) expander (d) evaporator

Q.2 (a) Give the definition of (1) close system (2) open system (3) isolated system 03

(b)

(c)

Define the heat and give the comparison of heat and work.

Explain steam formation with figure also draw T-H diagram. 04

07

Q.3 (a) Define the terms 1.Melting point 2.Boiling point 3.Critical point 03

(b)

(c)

Give the classification of boilers.

Draw the figure of Cochran boiler and explain its construction and working. 04

07

Q.4 (a) State Zeroth law of thermodynamics. 03

(b)

(c)

Prove that CP - CV= R.

In air compressor, air enters at 1.013 bar and 270C having volume of 5 m3/ kg

and it is compressed to 12 bar isothermally. Determine (i) work done (ii) heat

transfer, and (iii) change in internal energy.

04

07

Q.5 (a) Give comparison between Petrol and Diesel Engine. 03

(b)

(c)

What is boiler mountings and accessories? Also give the list of it.

A six cylinder 4 stroke I.C. engine is to produce 95 kW brake power at 800

rpm. The stroke to bore ratio is 1.25, mean effective pressure is 7 bar.

Determine the bore and stroke of the engine. Assume mechanical efficiency

as 80%.

04

07

Q.6 (a) What is priming? Why it is required in centrifugal pump but not in

reciprocating pump. 03

(b)

(c)

What is compressor? Give the classification of Rotary Compressors.

Explain Vapor Compression Refrigeration system with neat sketch. Also

draw p-h and T-s diagram for the same.

04

07

Q.7 (a) Classify properties of engineering material. 03

(b)

(c)

Explain flange coupling with neat sketch

What is brake? Describe an internal expanding shoe brake with a neat sketch

and state its applications.

04

07

***********


GUJARAT TECHNOLOGICAL UNIVERSITY BE SEMESTER 1st / 2nd (NEW) EXAMINATION WINTER 2016

Subject Code: 2110006 Date: 23/01/2017


Time: 10:30 AM TO 1:00 PM Total Marks: 70 Instructions:




4. Use of property table is permitted.

Q.1 Objective Question (MCQ): Choose right answer. Mark (a) 07

1. The sum of internal energy (U) and the product of pressure and volume (p.v) is

known as

A. workdone

B. entropy

C. enthalpy

D. heat

2. The energy which is not derived from the sun is ______.

A. bio-mass

B. fossil fuels

C. nuclear energy

D. geo-thermal energy

3. An adiabatic process is one in which

A. no heat enters or leaves the gas

B. the temperature of the gas changes

C. the change in internal energy is equal to the mechanical work done

D. all of the above

4. The ratio of specific heat at constant pressure (cp) and specific heat at constant

volume (cv) is

A. equal to one

B. less than one

C. greater than one

D. none of these

5. Superheated vapour behaves

A. exactly as gas

B. as steam

C. as ordinary vapour

D. approximately as a gas

6. The behaviour of a perfect gas, undergoing any change in the variables which

control physical properties, is governed by

A. Boyle's law

B. Charles' law

C. Gay-Lussac law

D. all of these

7. The efficiency of Diesel cycle increases with

A. decrease in cut-off

B. increase in cut-off

C. constant cut-off

D. none of these

(b) 07

1. Which of the following statement is correct?

A. A fire tube boiler occupies less space than a water tube boiler, for a given

power.

B. Steam at a high pressure and in large quantities can be produced with a

simple vertical boiler.

C. A simple vertical boiler has one fire tube.

D. all of the above

2. The compression ratio for petrol engine is

A. 3 to 6

B. 5 to 8

C. 15 to 20

D. 20 to 30

3. The impeller of a centrifugal pump may have

A. volute casing

B. volute casing with guide blades

C. vortex casing

D. any one of these

4. The maximum delivery pressure in a rotary air compressor is

A. 10 bar

B. 20 bar

C. 30 bar

D. 50 bar

5. During a refrigeration cycle, heat is rejected by the refrigerant in a

A. compressor

B. condenser

C. evaporator

D. expansion valve

6. A hydraulic coupling belongs to the category of

A. power absorbing machines

B. power developing machines

C. energy transfer machines

D. energy generating machines

7. An open belt drive is used when

A. shafts are arranged parallel and rotate in the opposite directions

B. shafts are arranged parallel and rotate in the same directions

C. shafts are arranged at right angles and rotate in one definite direction

D. driven shaft is to be started or stopped whenever desired without interfering

with the driving shaft

Q.2 (a) State Zeroth law, First law and Second law of thermodynamics. 03

(b)

(c)

Describe any four form of energy in 100 words.

A balloon of spherical shape 6 m in diameter is filled with hydrogen gas at a

pressure of 1 bar absolute and 20°C. At a later time, the pressure of gas is 94

per cent of its original pressure at the same temperature :

1) What mass of original gas must have escaped if the dimension of the

balloon is not changed?

2) Find the amount of heat to be removed to cause the same drop in pressure at

constant volume.

Take molecular weight for hydrogen, M = 2 and specific heat constant volume

for hydrogen, cv = 10400 J/kg.K

04

07

Q.3 (a) State Boyle’s, Charle’s and Avogadro law. 03

(b)

(c)

Identify the advantages and disadvantages of wind energy.

A rigid tank contains 10 kg of water at 90°C. If 8 kg of the water is in the liquid

form and the rest is in the vapor form. Draw p-V diagram and identify the point

in p-V diagram. Determine

1) the pressure in the tank

2) the volume of liquid and water vapour

04

07

3) quality (dryness fraction) of steam and

4) volume of the tank by using dryness fraction

Q.4 (a) Express the mathematical formula with standard notation/symbol of properties

for

1) Wetness fraction of steam

2) Enthalpy of superheated steam

3) Specific volume of wet steam

03

(b)

(c)

Explain the construction of Oldham’s coupling with neat sketch in 150 words.

Explain with neat sketch working of any one of the high pressure boiler in 300

words. Tell the two advantages and two disadvantages of it.

04

07

Q.5 (a) Define air standard efficiency. State any four assumptions considered for

analysis of air standard cycle. 03

(b)

(c)

In ideal Rankine cycle, the steam at inlet to turbine is saturated at a pressure of

35 bar and the exhaust pressure is 0.2 bar. Assume flow rate of 9.5 kg/s.

Determine :

1) The pump work,

2) The turbine work,

3) The Rankine efficiency,

4) The dryness at the end of expansion. Compare four stroke engine and two stroke engine based on following

point/criteria.

1) Number of piston strokes per cycle

2) Number of crank rotation per cycle

3) Number of power stroke per min

4) Power

5) Flywheel

6) Size for same power output 7) Thermal Efficiency and Mechanical Efficiency

04

07

Q.6 (a) Define following terms with respect to compressor.

1) Free air delivery

2) Capacity

3) Volumetric efficiency of an air compressor

03

(b)

(c)

A centrifugal pump handles water and drives by motor which consumes 32 kW.

The pump running at 2000 rpm. The motor efficiency is 92%. The height of

pump axis from sump water surface is 6 m and produces a delivery head of 24

m. The discharge rate of water is 260 m3/hr. Calculate the efficiency of pump.

Sketch fluid flow diagram with component of ideal vapour compression

refrigeration system. Sketch p-V, T-s, and p-h chart and show all

thermodynamic process of ideal superheated vapour compression refrigeration

system

04

07

Q.7 (a) Define following terms.

1) Ductility

2) Elasticity

3) Pump

03

(b)

(c)

Classify plain carbon steel. Compare their properties and application.

Compare belt drive, chain drive and gear drive based on following criteria :

1) Main elements

2) Application suitability w.r.t to distance and velocity ratio

3) Space requirement

4) Slip

5) Design & Manufacturing complexity

6) Life 7) Maintenance

04

07

***********

Seat No.: ________ Enrollment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER– 1st / 2nd EXAMINATION (NEW SYLLABUS) – SUMMER 2016

Subject Code: 2110006 Date:01/06/2016


Time: 02:30 PM to 5:00 PM Total Marks: 70 Instructions:




4. Use of steam table is allowable.

Q.1 Objective Question (MCQ) Mark (A) Select the correct answer 07

1. The S.I. unit N-m/s is called

(a)Watt (b) Joule (c) Calorie (d) None of the above.

2. The Universal gas Constant is equal to

(a) M/R (b) R/M (c) M*R (d) All of the above

3. The law PV = C is related to this process

(a)Adiabatic (b) Isobaric (c) Isochoric (d) Isothermal

4. Dryness fraction(x) of superheated steam is

(a)equal to 0 (b) greater than 1 (c) less than 1 (d) equal to 1

5. Cut-off ratio is related to

(a)Carnot cycle (b) Otto cycle (c) Diesel cycle (d) Rankine cycle

6. The compression ratio for Diesel engine is in the following range:

(a)12 to 22 (b) 5 to 10 (c) 10 to 12 (d) None of the above

7. Gear pump and Vane pump are types of

(a)Rotary pump (b) Reciprocating pump (c) Centrifugal pump

(d) None of the above.

(B) Select the correct answer 07

1. The work done on compressor is least when the compression is

(a)Isothermal (b) Adiabatic (c) Polytropic (d) None of the above

2. Inter cooling in multi stage compression is used to

(a) cool air (b) Minimize the work done (c) reduce volume of air

(d) none of the above.

3. In the domestic refrigerators the bank of tubes at the back of the

refrigerator are

(a)Condenser tubes (b) Evaporator tubes (c) Capillary tubes (d) All

of the above

4. Heat is absorbed by refrigerant during refrigeration cycle in

(a)Condenser (b) Evaporator (c) Capillary (d) None of the above

5. The unit of pressure is

(a)Pascal (b) N/m2 (c) bar (d) all of the above

6. The sealing ring for pressure cooker is made from

(a)Leather (b) Rubber (c) Plastic (d) Aluminum

7. Plate type, Cone type and Centrifugal type are the types of

(a)Couplings (b) Brakes (c) Clutches (d) Gear drives

Q.2 (a) Classify the engineering materials. 03

(b)

(c)

Explain with neat sketch the working of belt drives and gear drives.

What do you understand by the term 1 ton of refrigeration? What

are the main components of vapour compression refrigeration

system? Write their functions.

04

07

Q.3 (a) Differentiate between a Brake and a Clutch. 03

(b)

(c)

How the air compressors are classified based on different criteria.

Draw air standard diesel cycle on p-V and T-s diagrams. Derive its

efficiency equation with usual notations.

04

07

Q.4 (a) With neat sketch explain in brief the working of Vane pump. 03

(b)

(c)

Compare: S.I. engines and C.I. engines.

The following readings were recorded during the test on single

cylinder four stroke diesel engine.

(1)Cylinder diameter = 250 mm

(2) Stroke length = 350 mm

(3) Mean effective pressure = 6.7 bar

(4) Speed of engine = 250 r.p.m.

(5) Net brake load = 1070 N

(6) Effective brake drum diameter = 1.5 m

(7) Fuel consumption rate = 10 kg per hour.

(8) C.V. of the fuel = 44300 kJ/kg.

Calculate: (1) Indicated Power (2) Brake Power (3) Mechanical

efficiency. (4) Brake thermal efficiency.

04

07

Q.5 (a) Explain the difference between boiler mountings and accessories. 03

(b)

(c)

Calculate the air standard efficiency of the engine working on Otto

cycle in which air initially at 1 bar and 20°C is compressed

adiabatically to the pressure of 16 bar. Maximum pressure of cycle

is 45 bar and adiabatic index γ =1.4.

With neat sketch explain the construction and working of

(i) Fusible plug and (ii) Air pre heater.

04

07

Q.6 (a) Prove that Cp – Cv = R with usual notations. 03

(b)

(c)

Write a short note on ”Solar Energy”.

A cylinder contains 0.6 m3 of a gas at a pressure of 1 bar and 90 °C.

The gas is compressed to a volume of 0.18 m3 by the law PVn = C.

The pressure of gas at the end of compression is 5 bar.

Calculate: (1)Mass of gas (2) value of index n (3) The change in

internal energy of the gas. (4) Work done (5) The heat received or

rejected by the gas during the process. Take γ =1.4 and R= 0.294

kJ/kg K.

04

07

Q.7 (a) Explain in brief Open system and closed system giving examples. 03

(b)

(c)

Draw neat and labeled diagram of Cochran Boiler

Calculate the total amount of heat required to produce 6 kg of steam

at a pressure of 6 bar and temperature of 258 °C from the water at

30 °C. Take specific heat of steam = 2.1 kJ/kg-K. and the specific

heat of water = 4.187 kJ/kg-K.

04

07

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GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER–1st / 2nd (NEW) EXAMINATION – WINTER 2015

Subject Code: 2110006 Date: 23/12/2015 Subject Name: Elements of Mechanical Engineering Time: 10:30am to 01:00pm Total Marks: 70 Instructions:

1. Question No. 1 is compulsory. Attempt any four out of remaining Six questions. 2. Make suitable assumptions wherever necessary. 3. Figures to the right indicate full marks. 4. Steam tables are permitted.

Q.1 Objective Question (MCQ)

(a) 07 1. Prime mover is a device which converts natural resources into

____________ energy. (a) With decrease in pressure (b) with increase in pressure (c) is unaffected by pressure (d) none of the above

2. Zeroth law of thermodynamics forms the basis of measurement of the following. (a) heat exchange (b) work (c) pressure (d) Temperature

3. Polytropic expansion of a gas is given by the law (a) pVn = C (b) pVγ = C (c) pV = C (d) pV0 = C

4. Behaviour of vapour can be determined by (a) Boyles law (b) Charles law (c) Combined law (d) none of the above

5. Bucket pump is a type of ___________ pump. (a) rotary (b) Centrifugal (c) reciprocating (d) axial

6. Centrifugal compressor is suitable for producing? (a) High pressure (b) medium pressure (c) low pressure (d) all of the above

7. Spur gear has teeth__________to the axes of the gears. (a) inclined (b) parallel (c) perpendicular (d) any of the above

(b) 07 1. The energy absorbed by brakes is released in surrounding in form of

(a) heat energy (b) kinetic energy (c) potential energy (d) pressure energy

2. Which engine produces more power for same compression ratio (a) 4- stroke diesel engine (b) 4- stroke petrol engine (c) 2- stroke diesel engine (d) 2- stroke petrol engine

3. The operation of filling passage ways with liquid from outside source before starting pumps is known as____________. (a) cavitation (b) cleaning (c) priming (d) chocking

4. One ton of refrigeration is equal to (a) 221 kJ/min (b) 420 kJ/min (c) 600 kJ/min (d) 210 kJ/min

5. Belt drive provides_____________flexibilty compared to gear drive. (a) more (b) less (c) same (d) can’t say

6. Which of the following elements is used to connect two shafts____ (a) clutch (b) brakes (c) Couplings (d) none of above

7. ____________ is the characteristic of cast iron. (a) ductile (b) malleable (c) very brittle (d) all of the above

Q.2 (a) Write a short note on Global Warming. 03

(b)

(c)

Define isothermal process. Derive the expression for work done, change in internal energy and heat transfer for this process. One cubic meter of air at pressure of 1.5 bar and 80oC is compressed to final pressure 8 bar and volume 0.28 m3. Determine (i) mass of air (ii)

04 07

index of ‘n’ compression (iii) change in internal energy (iv) Heat transfer during compression. Take γ = 1.4 and R= 287 J/kgK.

Q.3 (a) Show the function and location of the following in the boiler plant: (i) Feed check valve (ii) Air superheater (iii) Fusible plug.

03

(b)

(c)

Explain Throttling calorimeter with neat sketch and calculation of dryness fraction. Sketch and explain a Babcock and Wilcox boiler.

04 07

Q.4 (a) Differentiate between Two stroke and Four stroke I.C engines. 03

(b)

(c)

Determine the quality of steam for the following cases: (i) P= 10 bar, v = 0.180 m3/kg (ii) P= 10 bar, t= 200oC (iii) P=25 bar , h = 2750 kJ/kg

Derive equation for air standard efficiency of Diesel cycle.

04

07

Q.5 (a) Explain the working principle of centrifugal pump with neat sketch? 03 (b)

(c)

The following data refers to a single cylinder 4 strokes petrol engine. Cylinder diameter = 30 cm, piston stroke = 40 cm, engine speed= 1400 r.p.m, indicated mean effective pressure = 5 bar, fuel consumption= 17.568 kg per hour, calorific value of the fuel is 45000 kJ/Kg; specific gravity of the fuel is 0.8. Determine the indicated thermal efficiency. Explain Vapor Compression Refrigeration system with neat sketch. Also draw p-h and T-s diagram for the same.

04 07

Q.6 (a) Define air-conditioning. Classify the air conditioning system in detail. 03

(b)

(c)

Why multi-stage compression is required? Write advantages of the multi-staging compression. What are the different types of couplings? Explain the centrifugal clutch.

04 07

Q.7 (a) Define the following mechanical properties

(i) Elasticity (ii) Toughness (iii) Ductility 03

(b) (c)

Explain the working principle of vane pump with neat sketch? What are bearings? Explain with neat sketch worm and worm wheel.

04 07

***********

1


GUJARAT TECHNOLOGICAL UNIVERSITY BE- SEMESTER– 1st / 2nd (NEW SYLLABUS) EXAMINATION – SUMMER 2015



Time: 10.30am-01.00pm Total Marks: 70 Instructions:

1. Question No. 1 is compulsory. Attempt any four out of remaining six questions.



Q.1 (a) Multiple choice questions: 07

1 Work is considered positive when

a) Work is done on the system b) work is done by the system c) both a and b d)

none of the above

2 A source of energy is known as renewable source

a) Fossil fuel b) Nuclear c) CNG d) All of the above

3 When driving and driven shafts are at comparatively larger distance apart, the

type of drive suitable is :

a) Gear drive b) Belt drive c) friction drive d) chain drive

4 The clutch ordinarily remains in disengaged condition when it is used for power

transmission in:

a) Automobile b) Machine tools c) Crane d) Elevator

5 Which of the following type of centrifugal pump converts kinetic energy of pump

into pressure energy:

a) Foot valve b) Casing c) Suction pipe d) Impeller

6 For earth moving machines, widely used engines are:

a) Petrol engine b) Steam engine c) Diesel engine d) Gas engine

7 The correct location of economizer is :

a) Between furnace and preheater b) between airpreheater and chimney

c) between forced draft fan and furnace d) near the superheater

OR

(a) Multiple choice questions: 07

1 COMPRESSOR is a machine which is used to do

A) lift liquid from low height to higher elevation B) To store liquid

C) To compress liquid OR gas. D) none of the above

2 Which of the following energy is converted into electricity in a Hydo power plant

A) Nuclear energy B) Potential Energy of water

C) Thermal Energy D) all of the above

3 Which of the following is a unit of Power.

A) Joules B) Watt

C) Meter D) kilogram

4 Which of the following instrument is used to measure temperature

A) Vernier calliper B) Manometer

C) Thermometer D) none of the above

5 In a simple gear train having two gears , if driving gear rotates in clockwise

direction then driven gear rotates in

A) Clockwise direction B) Anti clockwise direction

C) Depend on size of gear D) depend on no. of teeth

2

6 In a IC engine from which of the following source energy is converted into

mechanical energy

A) Chemical energy of fuel. B) potential energy

C) kinetic energy D) All of the above

7 Which of the following instrument is used for drawing curved lines

A) T- Square B) French curves

C) Protractor D) Compass

(b) Select the correct option: 07

1. Water after being pumped into a boiler cannot come out because of:

a) Steam stop valve b) Feed check valve c) Safety valve d) Blow off valve

2. For the same compression ratio, the thermal efficiency of otto cycle is :

a) Greater than Diesel engine b) less than Diesel engine c) equal to Diesel

Engine d) None of the above

3. Diesel cycle consists of :

a) Two isentropic process and two isothermal process b) two isentropic, one

constant pressure, one constant volume process c) two isothermal and two

constant pressure process d) two isentropic, Two constant volume process

4. Dryness fraction of a steam (x) is given by:

a) ms / mw b) mw / ms c) (ms + 1) / mw d) ms / (ms +mw )

5. The material for making packing for covering steam pipes to avoid heat transfer,

are made up of :

a) Asbestos b) Gold c) Iron d) Aluminum

6. The relation between Cp and Cv is:

a) Cp - Cv = R b) Cv - Cp c) Cp + Cv = R d) Cp . Cv

7 Specific heat is defined as the amount required

a) To raise unit degree of temperature of a substance

b) To raise unit mass of a substance through unit degree of temperature

c) To raise unit mass of a substance through 10°C

d) None of the above.

Q.2 (a) Define the following terms:

i) Higher calorific value ii) Mountings and accessories of boiler

iii) critical point and triple point of water.

03

(b)

(c)

Differentiate:

(i) Belt drive, chain drive and gear drive

(ii) Brake and Clutch

Mention different parts of vapor compression refrigeration cycle along with their

functions. Also draw a neat diagram of vapor compression refrigeration cycle.

04

07

Q.3 (a)

(b)

List methods of measuring dryness fraction. Explain any one of them.

Determine the work done in compressing one kg of air from a volume of 0.15m3

at a pressure of 1 bar to a volume of 0.05 m3, when the compression is 1)

adiabatic 2) isothermal. Take ᵞ = 1.4. Give your comments.

07

07

Q.4 (a) Explain water Temperature- Enthalpy Diagram for water. 07

(b) What amount of heat is required to produce 5 kg of steam at a pressure of 5 bar

and temperature of 250°C from water at 30°C, take Cps =2.1kJ/kg K

07

Q.5 (a) Discuss Rankine cycle in detail with flow diagram and P-V diagram. 07

3

(b) An engine working on ideal Otto cycle has a clearance volume of 0.03m3 and

swept volume of 0.12m3. The temperature and pressure at the beginning of

compression are 100°C and 1 bar respectively. If the pressure at the end of heat

addition is 25 bar, calculate i) ideal efficiency of the cycle. ii) Temperature at key

points of the cycle. Take ᵞ = 1.4 for air.

07

Q.6 (a) Classify Air Compressors. Give the uses or application of compressed air. 07

(b) During testing of single cylinder two stroke petrol engine, following data is

obtained: Brake torque 640 Nm, cylinder diameter 21 cm, Speed 350 rpm, stroke

28 cm, mean effective pressure 5.6 bar, oil consumption 8.16 kg/hr, C.V = 42705

kJ/kg. Find, i) Mechanical Efficiency, ii) Indicated thermal efficiency iii) brake

thermal efficiency iv) brake specific fuel consumption.

07

Q.7 (a) Explain flange coupling with neat sketch 07

(b) Classify properties of engineering material. Explain any three of them. 07

*************


GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER– 1

st / 2

nd EXAMINATION (New Syllabus) – WINTER 2014

Subject Code: 2110006 Date: 26-12-2014


Time: 10.30a.m.-01.00a.m. Total Marks: 70 Instructions:

1. Question No. 1 is compulsory. Attempt any Four out of remaining Six questions.



4. Use of Steam Tables is permitted

Q.1 MARKS

(a) Answer the given MCQ. 07

1. The unit of work is

(a) N.m (b) Joule (c) kg.m2/s

2 (d) all the above

2. The function of ozone layer is (a) protects the earth from harmful effect of ultraviolet rays

(b) increase the temperature of earth

(c) increases CO2 in atmosphere

(d) none of the above

3. In the Polytropic Process PVn= C, if n = ∞ , the process is called

(a) isochoric (b) isobaric (c) isothermal (d) adiabatic

4. Saturation temperature of steam increase (a) With decrease in pressure (b) with increase in pressure

(c) is unaffected by pressure (d) none of the above

5. During adiabatic process (a) heat transfer is zero (b) work transfer is zero (c) enthalpy remains constant

(d) enthalpy change is zero.

6. The processes of Carnot cycle are

(a)Two adiabatic and two constant volume (b)Two constant pressure and two constant volume

(c)Two isothermal and two adiabatic

(d)Two isothermal and two isentropic

7. The air standard cycle on which the petrol engine work is

(a) Otto cycle (b) Carnot cycle (c) Joule cycle (d) Dual cycle

OR

(a) Answer the given MCQ. 07

1. Pump is a machine which is used to do A) lift liquid from low height to higher elevation B) To store liquid

C) To compress liquid D) none of the above

2. which of the following energy is converted into electricity in a Hydo power plant

A) Nuclear energy B) Potential Energy of water C) Thermal Energy D) all of the above

3. which of the following is a unit of Electric current

A) Ampere B) Volt C) Meter D) kilogram

4. Which of the following instrument is used to measure length

A) Vernier calliper B) Manometer

C) Thermometer D) none of the above

5. In a simple gear train having two gears , if driving gear rotates in clockwise

direction then driven gear rotates in

A) Clockwise direction B) Anti clockwise direction C) depend on size of gear D) depend on no. of teeth

6. In a IC engine which energy is converted into mechanical energy

A) Chemical energy of fuel. B) potential energy C) kinetic energy D) All of the above

7. which of the following instrument is used for drawing a straight lines A) T- Square B) French curves

C) Protractor D) Compass

(b) Answer the given MCQ. 07

1. Which of the following are boiler mountings?

(a) Economiser (b) Fusible Plug (c) Super heater (d) Air preheater

2. The function of steam stop valve is

(a) to regulate flow of steam from boiler to steam pipe

(b) to separate steam from water

(c ) to collect steam from steam drum (d) to provide safety of boiler

3. Petrol engine is

(a) Compression ignition engine (b) Spark ignition engine (c) mixed ignition engine (d) all of the above

4. Which of the following is a positive belt drive.

(a) V-belt (b) flat belt (c) Cross belt (d) timing belt

5. A operation of filling passage ways with liquid from outside source before starting

pumps is known as

(a) cavitation (b) cleaning (c) priming (d) chocking

6. _________is the ability of a material to resist deformation under stress. (a) strength (b) stiffness (c) hardness (d) brittleness

7. A one ton refrigeration system means that its refrigerating system is

(a) 50 KJ/min (b) 210 KJ/min (c) 300 KJ/min (d) 350 KJ/min

Q.2 (a) Write a short note on solar energy? 03

(b)

(c)

Explain Barrel calorimeter with neat sketch.

One kg of gas is compressed polytropically from 160 kpa pressure and 280 K

temperature to 760 KPa. The compression is according to law PV1.3

=

Constant. Find: (1) Final Temperature (2) work done (3) change in internal

energy (4) amount of heat transfer and (5) change in enthalpy. Take R=0.287

KJ/KgK and Cp= 1.002 KJ/KgK.

04

07

Q.3 (a) Show the function and location of the following in the boiler plant:

(i) Economiser (ii) Steam stop valve (iii) Fusible plug. 03

(b)

(c)

Derive Cp-Cv=R, with usual notations.

1.5 kg of steam at a pressure of 10 bar and temperature of 2500C is expanded

until the pressure becomes 2.8 bar. The dryness fraction of steam is then 0.9.

Calculate change in internal energy.

04

07

Q.4 (a) Compare Rankine cycle with Carnot cycle. 03

(b)

(c)

In an Otto cycle the compression ratio is 10. The temperature at the

beginning of compression and at the end of heat supply is 300 K and 1600 K

respectively. Assume, γ = 1.4 and Cv= 0.717 KJ/KgK.

Find: (i) Heat supplied (ii) Efficiency of the cycle.

Sketch and explain a Cochran boiler.

04

07

Q.5 (a) Explain with the help of neat sketches, the working of two stroke petrol

engine.

07

(b) Derive an equation for air standard efficiency of Otto cycle. 07

Q.6 (a) Explain working of a centrifugal pump. 03

(b)

(c)

What is compressor? Give uses of compressed air.

Explain Vapor Compression Refrigeration system with neat sketch. Also

draw p-h and T-s diagram for the same.

04

07

Q.7 (a) Define the following mechanical properties

(i) Ductility (ii) Hardness (iii) Plasticity 03

(b)

(c)

What is belt drive? Describe briefly types of belt drives.

What is coupling? Explain internal expanding shoe brake with a neat sketch? 04

07

*************



st / 2

nd EXAMINATION – SUMMER 2014

Subject Code: 2110006 Date:18-06-2014


Time: 02:30pm to 05:00 pm Total Marks: 70 Instructions:

1. Question No. 1 is compulsory. Attempt any four out of remaining six questions.



Q.1 (a) Objective Questions 07

1. Which of the following is not a unit of distance?

(a) Light year (b) Angstrom (c) Mile (d) Carat

2. The specific heat at constant pressure(Cp) of an ideal gas is

(a) Equal to its specific heat at constant pressure

(b) Cp < Cv (c) Cp > Cv (d) Cp = 2 Cv

3. The process of sublimation is found to occur in

(a) Liquid N2 (b) Solid CO2 (c) Solid O2 (d) Air

4. If x1 and x2 are the dryness fractions obtained in separating calorimeter and throttling

calorimeter respectively, then actual dryness fraction of steam is_______

(a) x1 · x2 (b) X1 + X2 / 2 (c) X1 + X2 (d) X1 ▬ X2

5. The process of Carnot cycle are

(a) Two isothermal and two constant volume

(b) Two constant pressure and two constant volume

(c) Two isothermal and two isentropic

(d) Two isothermal and two adiabatic

6. A device which is used for pumping water into the boiler is called

(a) Economizer (b) Feed pump

(c) Injector (d) Air preheater

7. Which part used in I.C.Engine to convert reciprocating motion of piston to rotary

motion of output shaft

(a) Connecting road (b) Crank shaft (c) Cam shaft (d) Gudgeon pin

(b) Objective Questions 07

1. Which are of the following is not a rotary pump?

(a) Gear pump (b) Vane pump (c) Screw pump (d) Axial pump

2. Which one of the externally fired boiler.

(a) Babcock and Wilcox (b) Lancashire

(c) Cochran (d) All of the above

3. The chemical formula of R-12 is

(a) CCl2F (b) CClF3 (c) CCl2F2 (d) CHClF2

4. Which types of coupling used to connecting shafts, whose axis are parallel but not in

one line?

(a)muff coupling (b)flexible coupling (c)Oldham’s coupling (d) flange coupling

5. Compressor in which compression of air from suction pressure to delivery pressure

takes place in more than one cylinder is called___________compressor.

(a) Single acting (b) Double acting

(c) Single stage (d) Multi stage

6. The ability of a material to resist fracture due to high impact loads is called

(a)strength (b)stiffness (c) toughness (d) brittleness

7. Which property is called Intensive property?

(a)Kinetic energy (b)viscosity (c)Internal energy (d)magnetization

Q.2 (a) (I) Write a short-note on bio-fuels. 03

(II) Explain Specific heat. Give Statements of Zeroth Law and First law of

thermodynamics. 04

(b) 1 kg of air at 9 bar pressure and 80o

C temperature undergoes a non-flow work

polytropic process. The law of expansion is PV1.1

= C. The pressure falls to 1.4 bar

during process. Calculate (1) Final temperature (2) Work done (3) Change in internal

energy (4) Heat exchange. Take R=287 J/kg and γ = 1.4 for air.

07

Q.3 (a) (I) state & Explain Charles’s law. 03

(II) Prove the equation of work done for Isothermal process. 04

(b) Calculate the internal energy per kg of superheated steam at 10 bar and a temperature

of 3000C. Find also change in internal energy if this steam is expanded to 1.4 bar and

dryness fraction 0.8.

07

Q.4 (a) Explain Cochran boiler with neat sketch & give its advantages and disadvantages. 07

(b) Write a short note on Separating calorimeter with its limitations. 07

Q.5 (a) Explain working of four stroke petrol engine with neat sketch & P-V diagram. 07

(b) A four cylinder two stroke petrol engine with stroke to bore ratio 1.2 develops 35 kW

brake power at 2200 rpm. The mean effective pressure in each cylinder is 9 bar and

mechanical efficiency is 78 %. Determine (1) Diameter and stroke of each cylinder

(2) Brake thermal efficiency (3) indicated thermal efficiency. If fuel consumption 8

kg / hr having C.V=43000 kJ/kg.

07

Q.6 (a) What do you mean by priming of centrifugal pump? Explain single acting

reciprocating pump. 07

(b) An engine operates on the air standard diesel cycle. The conditions at the start of the

compression stroke are 353 K and 100 kPa , while at the end of compression stroke

the pressure is 4 MPa. The energy absorbed is 700 kJ/kg of air. Calculate (1) the

compression ratio (2) the cut-off ratio (3) the work done per kg air (4) the thermal

efficiency.

07

Q.7 (a) (I) What should be the properties of common refrigerants? 03

(II) Explain Function and working of Fusible plug used in boiler. 04

(b) Explain types of belt drive. 07 *************

1/2



st / 2

nd EXAMINATION (New Syllabus) – WINTER 2013



Time: 10:30 am to 1:00 pm Total Marks: 70 Instructions:




Q.1 (a) Objective Questions: 07

1. Pump is a

(a) power producing machine (b) power consuming machine (c) universal machine

(d) all of above

2. Spark plug is used in

(a) petrol engine (b) diesel engine (c) steam engine (d) boiler

3. Cochran boiler is

(a) fire tube (b) water tube (c) single tube (d) none of these

4. Wind velocity is measured by

(a) manometer (b) tachometer (c) anemometer (d) thermometer

5. If load on the bearing acts perpendicular to the axis of the shaft then bearing is

known as

(a) journal bearing (b) thrust bearing (c) bushed bearing (d) radial bearing

6. When rotary motion is to be converted into linear motion following gear

arrangement is used

(a) spur gear (b) spiral gear (c) rack and pinion gear (d) none of these

7. Which power transmission element is used in motor cycle?

(a) rope (b) flat belt (c) chain (d) V belt

(b) Objective Questions: 07

1. The first law of thermodynamic is the law of

(a) energy conservation (b) heat transfer (c) work transfer (d) all of these

2. Gauge pressure is measured with respect to

(a) absolute zero pressure (b) atmospheric pressure (c) vacuum pressure (d) all of

these

3. The phase change from solid to vapour is called

(a) sublimation (b) vaporization (c) pressurization (d) temperature

4. Which coal is having the highest calorific value?

(a) bituminous coal (b) lignite coal (c) anthracite coal (d) coke

5. Internal energy of a gas is a function of

(a) enthalpy (b) pressure (c) pressure and volume (d) temperature

6. Following is not a component of Rankine Cycle

(a) boiler (b) turbine (c) condenser (d) compressor

7. In a domestic vapour compression refrigerator the refrigerant commonly used is

(a) ammonia (b) air (c) CO2 (d) Freon-12

2/2

Q.2 (a) What is an adiabatic process? For adiabatic process with the usual notation prove

PVγ = constant.

07

(b) Determine enthalpy and internal energy of 1 kg of steam at a pressure of 12 bar

when (i) the dryness fraction of steam is 0.8 (ii) steam is dry and saturated

(iii) steam is superheated to 2800 C. Take Cps = 2.1 kJ/kg K.

07

Q.3 (a) Give detailed classification of fuel. Write short note on wind energy. 07

(b) An air at 150 C and 1 bar is compressed adiabatically to 15 bar by an engine

working on Otto cycle. The maximum pressure of the cycle is 40 bar. Calculate air

standard efficiency, mean effective pressure. Take Cv = 0.718 kJ/kg K and R =

0.287 kJ/kg K.

07

Q.4 (a) Differentiate between fire tube and water tube boiler. Explain Babcock and Wilcox

boiler construction with neat sketch. 07

(b) Explain economiser and air-preheater with neat sketch. 07

Q.5 (a) What is throttling process? Explain throttling calorimeter with neat sketch. Derive

equation for dryness fraction. 07

(b) During testing of single cylinder two stroke petrol engine following data were

obtained. Brake torque 640Nm, cylinder diameter 21cm, speed 350 rpm, stroke

length 28 cm, mean effective pressure 5.6 bar, oil consumption 8.16 kg/hr, CV

42705 kJ/kg.

Determine (i) mechanical efficiency (ii) Indicated thermal efficiency (iii) Brake

thermal efficiency (iv) brake specific fuel consumption.

07

Q.6 (a) What is compressor? Explain working of double acting reciprocating pump and

bucket pump with neat sketch. 07

(b) What is refrigeration? What is refrigeration effect? Explain window air conditioner

with neat sketch. 07

Q.7 (a) What is brake? Describe an internal expanding shoe brake with a neat sketch and

state its applications. 07

(b) (1) Sketch and describe helical and bevel gear and state applications of each.

(2) Define elasticity, rigidity, hardness, fatigue, ductility, brittleness. 04

03

*************

1/1


GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER– 1st / 2nd • EXAMINATION – SUMMER 2013

Subject Code: 110006 Date: 11-06-2013 Subject Name: Elements of Mechanical Engineering Time: 02:30 pm – 05:00 pm Total Marks: 70 Instructions:

1. Attempt any five questions. 2. Make suitable assumptions wherever necessary. 3. Figures to the right indicate full marks.

Q.1 (a) Explain working of four stroke Diesel Engine with P-V diagram. 05

(b) A four cylinder four stroke petrol engine has 100mm bore and stroke is 1.3 times bore. It consumes 4 kg of fuel per hour having calorific value of 40500 kJ/kg. If engine speed is 850 rpm. Find its Indicated thermal efficiency. The mean effective pressure is 0.75 N/mm2

05

(c) Define Pressure and explain Absolute Pressure, Guage Pressure and Atmospheric pressure.

04

Q.2 (a) Explain construction and working of Locomotive boiler with neat sketch. 07

(b) State the function of the following (1) Fusible plug. (2) Economiser (3) Safety valve

03

(c) Define : (i) Sensible heat (ii) Latent heat (iii)Dryness fraction (iv)Enthalpy of evaporation.

04

Q.3 (a) Derive Expression PV/T=constant with the help of Boyle’s law and

Charle’s law. 05

(b) A steel cylinder contains O2 at pressure of 25 bar and temperature of 270C, After using some quantity of the gas the pressure was found to be 5 bar and temperature of 200C.700 liters of O2 was originally put in the cylinder at NTP Density of O2 at NTP is 1.43 gm/liter. Find the mass of O2 used.

06

(c) Define Calorific value and explain Higher and Lower Calorific values. 03

Q.4 (a) Explain Separating Calorimeter with neat sketch. 05 (b) Find internal energy of 1 kg of steam at a pressure of 15 bar when

(i) The steam is superheated with temperature of 4000C. (ii) The steam is wet with dryness fraction =0.9

Take Cps=2.1 kJ/kg K

05

(c) What are different methods of IC engine governing? Explain governing method used in the Petrol engine.

04

Q.5

(a) Derive expression for the efficiency of the Carnot cycle.

05

(b) In an ideal Diesel cycle the temperature at the beginning and at the end of compression are 570C and 6030C. The temperature at the beginning and at the end of expansion are 19500C and 8700C.Find the ideal efficiency of the cycle. If the pressure is 1 bar find the maximum pressure in the cycle.

05

(c) Explain Oldham’s coupling with neat sketch. 04

Q. 6 (a) Explain working of main parts of centrifugal pump with neat sketch. 05 (b) Explain difference between Reciprocating and Rotodynamic compressor. 05 (c) Draw and explain Internal expanding brake. 04

Q.7 (a) Explain Vapour absorption Refrigeration system with the neat sketch. 06 (b) Define (i) Hardness (ii) Creep (iii) Resilience (iv) Toughness. 04 (c) What are Bearings and how they are classified? 04

***************

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