GAUHATI UNIVERSITY

SYLLABUS FOR FOURTH YEAR B. E. COURSE (1996 REVISION)

Department of Mechanical Engineering

SEVENTH SEMESTER (MECHANICAL):

ME 776 : MECHANICAL VIBRATIONS (4 – 2 – 0)

Theory – 100

Sessional – 75

Basic concepts:

Vibration and its cause, elements, scope of study, degrees of freedom, free and forced vibration, types of damping, vibration models, equivalent springs. Vibration problems – Methods of analysis, D’ Alembert’s Principles, Energy method, Lagrange’s equation. Lagrangian, Hamiltonian , Classification of Mechanical system, Equation of motion.

Single Degree of Freedom System:

Free vibration without damping – longitudinal, transverse and torsional. Free damped vibration – critical damping, logarithmic decrement. Forced damping – harmonic force, constant force, Force unbalance – reciprocatory, rotary and torsional vibration – Geared system, critical or whirling speeds – Elasticity of bearing and supports. Vibration isolation, Force and motion transmissibility, Absorber, Self excited vibration, Semi-definite system, Coulomb damping, Energy dissipated by damping, Structural damping, Complex stiffness, Brief introduction to non-linear vibration. Response to general periodic excitation. Fourier Series, Impulse response, Step response.

Two degrees of freedom system:

Normal modes and natural frequencies, Torsional vibration, Dynamic vibration absorber – Vibration damper, Beat phenomenon, Response to harmonic excitation.

Solution by computer:

Finite difference numerical computation, Brief introduction to Analog computers.

Multi-degree Freedom System:

Introduction to vibration of continuous media – longitudinal, transverse and torsional system. Solution of vibration problems – Matrix method, Holzer method, Rayleigh – Ritz method.

Vibration measuring instruments: Frequency, displacement, velocity and acceleration measuring instruments, Seismic types.

Suggested Books:

1. T S Rao and K Gupta, Introductory course on theory and practice of Mechanical Vibrators: New Age International Publishers.

2. T S Rao, Advanced theory of Vibration Analysis, McGraw Hill International.

3. L Maitrovich, Elements of Vibration Analysis, McGraw Hill International.

4. W T Thomson, Theory of Vibration and Applications, Prentice Hall.

5. A A Shabana, Theory of Vibration, Vol. I & II, Springer.

ME 777 : ENGINEERING INSPECTION AND METROLOGY ( 3 – 1 – 2 )

Theory : 100

Sessional : 50 + 25 (Lab)

Controlling quality through inspection.

Types of inspection – 100% inspection.

Statistical methods.

Sampling – Representative sample.

Product variations – Chance causes, assignable causes.

Control charts.

Range.

Computer applications.

Interchangeability – its ipmortance in production and advantages.

Types of interchangeability – Universal or full interchangeability , Selective assembly , matched fit.

Inspection gauges and shop gauges and sub-standards. Limits, Fits and Tolerances and allowances on gauge.

Limit gauges – hole and plug gauge.

Taylor principle of gauging.

Tool-makers microscope.

Principle of amplification – Mechanical, Optical, Optomechanical, Electrical, Pneumatic, Special devices for measurement of accuracy of threads and gears.

Measurement of surface.

Fineness – Measure for roughness – Use of stylus instrument. Interroferometry – Principle of interference. Use of optical flat, Gauge interferometer – Principle NPL gauge interferometer. Laser interferometer.

Alignment testing – Optical method, Laser alignment testing.  

Books:

1. Dimensional metrology – by M K Khare and S Vajpayee.

ME 778 : HEAT TRANSFER - II ( 4 – 2 – 0 )

Theory : 100

Sessional : 75

A. Fundamentals of Convective Heat Transfer:

Introduction; The convective heat transfer co-efficient; The basic equations viz. the continuity, the momentum (Navier – Stokes) and the continuity equations. The boundary layer concept- the velocity boundary layer, the thermal boundary layer, the boundary layer equations (Approximations); Velocity and thermal boundary layer development in a circular pipe; the concept of entry length and fully developed region.

B. Forced convective systems:

Forced convection over a flat-plate (External flow); the momentum and energy integral equations, integral approach ( approx. method) to evaluate drag co-efficient, drag force and the heat transfer co-efficient in the laminar boundary layer region, analog between momentum and energy transfer, drag co-efficients for turbulent boundary layerregion. Heat transfer and temperature distribution for flow between parallel plates.

Forced convection in circular tubes ( Internal flow); Energy equation ( in cylindrical co-ordinates) for thermal boundary layers, Heat transfer co-efficient for laminar flow in tubes under conditions of - constant heat flux, constant wall temperature; slug flow, fully developed flow; Analogy between momentum and heat transfer for turbulent flow through tubes. Convection correlations for turbulent flow through tubes; Convection correlations for non-circular ducts.

C. Free Convection:

Laminar boundary layer equations of free convection on a vertical flat-plate; concept of Grashoff number. Empirical correlations for vertical plates, horizontal plates, inclined surface, vertical and horizontal cylinders, spheres.

D. Heat exchanger analysis:

Types; Overall heat transfer co-efficient. Fouling factor, LMTD methods of analysis, Effectiveness – NTU method. Pressure drop and pumping power.

E. Design of heat exchangers:

Aspects of design, double pipe heat exchanger; Shell and tube heat exchanger; Condensers, Optimization of heat exchangers.

F. Boiling and Condensation:

Boiling heat transfer phenomena, Boiling correlations, Laminar film-wise condensation on a vertical plate, Turbulent film-wise condensation, Film-wise condensation on and inside horizontal tubes, Condensation in the presence of non-condensable gas.

G. Convective mass transfer:

Convective mass transfer co-efficient; the concentration boundary layer. Analogy between momentum, heat and mass transfer, Convective mass transfer correlation, evaporation of water into air.

H. Dimensional analysis:

Application to free and forced convection; application to convective mass transfer.

Recommended books:

1. A basic approach to heat transfer – by M N Ožišik

2. Fundamentals fo heat transfer – by Sachdeva

 ME 779 : APPLIED THERMODYNAMICS – II (4-2-0)

Theory – 100

Sessional – 75

Chapter 1 : I. C. Engines

Review of Otto, Diesel and Dual cycles; Air-standard efficiency, thermal efficiency and relative efficiency; Classification of I C Engines. Basic constructions of an IC engine system. Fuel supply systems; control system, lubrication systems, ignition system. Combustion in S I Engines – Knocking. Rating of I C Engine fuels. Combustion in C I Engines – Diesel knock. Rating of C I Engine fuels. Supercharging and scavenging of I C Engines. Engine performance and testing – power, fuel consumption and efficiencies. Heat balance charts.

Chapter 2: Air Compressors

Introduction; Reciprocating type – Single stage and multi-stage, Compression ratio and volumetric efficiency, effect of clearance, compressor efficiencies. Methods for improving thermal efficiencies. Compressor work and power. Intercooler and aftercooler. Rotary compressors – Classification, Cenrifugal compressors – theory of operations, impeller and diffuser, impeller work; efficiency. Rotary Vs Reciprocating compressor. Introduction to axial flow compressors, charging and choking of compressors.

Chapter 3: Gas Turbine

Introduction – gas turbine cycles – open and closed, Ideal and Actual cycles. Isentropic efficiencies and thermal efficiencies. Power output. Methods to improve thermal eficiencies; Gas turbine Vs I C Engines. Principles of Jet and Rocket propulsion.

Chapter 4: Refrigeration

Inroduction – Reversed Carnot cycle and air refrigeration cycles; COP; Capacity of a refrigerating unit. Vapour compression and vapour absorption cycles. Properties of refrigerants. Heat pump.

Chapter 5: Psychrometry

Introduction; Psychrometric terms; Delton’s law of partial pressures. Psychrometric processes. Psychrometric chart. Psychrometr.

Reference books:

1. Applied thermodynamics --- T. D. Eastor and A McConkey, ELBS (Longman)

2. Thermal Engineering --- P. L. Ballaney.

ME 780 * (1) : Elective – I : HYDRAULIC MACHINES (4-2-0)

Theory – 100

Sessional – 75

Review of Euler equation for turbomachinery: Radial, axial and mixed flow machines. Impulse and reaction machines. Specific speed, specific diameter, efficiency, cordier diagram.

Turbines:

Pelton wheel, wheel diameter, jet diameter, bucket shape and size and number, speed control of pelton wheel. Use of pelton wheel and efficiency, specific speed and specific diameter range.

Francis – Runner , flow and speed ratio, casting guide, vanes, flow control, speed control, runner shape variation with the change of specific speed. Draft tube, charge tank, penstock, cavitation.

Axial flow turbine and Kaplan turbine. Blade profile, specific speed, diameter change of blade, pitch, guide vane, flow control, cavitation characteristics, draft tube, speed control of Kaplan turbines. Centrifugal pumps – Single-stage and multistage, radial and mixed flow pump. Vane pump, Volute casing pump. Pump efficiencies – hydraulic efficiency, overall efficiency, losses in pump, Speed ratio, efficiency. Pump characteristics – surging, cavitation in pump. Priming of centrifugal pumps, self-priming of pumps, Multi-stage pumps, runner, casing and stationary vanes.

Axial pump – Specific speed, flow ratio, speed ratio characteristics, application. Propeller pump, blade-shape and aerofoil analysis – left drag and esimate of pressure rise and power requirements.

Fluid couplings.

Hydraulic dynamometer.

Reciprocating pumps.

Gear pumps.   

ME 780*(2) : Elective – I : REFRIGERATION (4-2-0)

Theory – 100

Sessional – 75

Refrigeration: Introduction, history, methods of refrigeration, Ice, Evaporation expansion of air, throttling of gas, vapour compression and absorption, steam jet, liquid gas, dry ice, units of refr. Difference between engine, refrigerator and heat pump.

Air Refrigeration System: Simple cycles – Carnot and Bell-Coleman; Boot – strap, Regenerative & reduced ambient system;Air-craft refrigearting system; Actual cycles remming; Advantages and disadvantages.

Vapour Compression Systems: Analysis of simple cycles, representation of TS, pH plans; methods of improving COP; Deviations of actual cycles from theoretical cycles. Compound compression with liquid flash cooler, flash inter-cooler multiple systems – COP, power required.

Vapor Absorber Ref. System: Thermodynamical analysis of systems, Advantages and disadvantages, Components, Practical systems NHe Watt. Water LiBr, Electrolux systems.

Non – Conventional Ref. System: Steam jet ref. Thermoelectric, Vortex tube refr. – merits and demerits and applications.

Refrigerants: Nomenclature, classification, desirable properties. Important refrigerants and their comparisons, selection of refrigerants.

Ref. Equipment: Compressors, condensers, expansion devices, evaporators, piping , line valves, solenoid valves, oil separators, driers, filters, moisture indicators, purging and controls.

Application of Refrigeration: Production of dry ice, cascading, multi-staging domestic, commercial, industrial and medical, preservator of food-spoilage, methods of preservation, cold storage, preparing of insulating materials using in ref. Systems.  

Recommended books:

1. Refrigeration and Air – conditioning -- M. Prasad

2. Refrigeration and Air – conditioning -- C. P. Arora.

ME 780 * (3) : Elective – I MACHINE TOOLS ( 4-2-0)

Theory – 100

Sessional – 75

Chapter–I: Metal cutting fundamental principles. Forcesacting on the cutting tools. Merchant’s theory of metal cutting. Vibration and chatter during metal cutting processes.Tool wear, tool life in relation to speed and surface.

Chapter – II: Design and constructional prinsiples of machines tools. Basic features of construction and fundamental kinetics requirements of machine tools.

Kinematic drives of machine tools – selection of range of speeds and feeds; layout in G P. – Ray diagrams for machine tools, gear boxes sliding and clutches drives. Feed gear-box analysis.

Chapter – III: Considerations affecting the design of machine tools (Lathe, Milling and drilling machines) with reference to their purpose, strength, rigidity and accuracy.

Single purpose and general purpose machine tools – effect on design.

Chapter – IV: Application of hydraulic drives – circuit diagram, pumps and valves. Its effect on power consumption and surface finish.

Chapter V : Electric equipments for machine tools. Characteristics demanded from the machine tools.

Chapter VI: Automation in machine tools – Capstan and Turret lathe and their operation lay out. Single spindle automatic screw cutting machine tools and their cam lay out. Swiss type automatics.

Economics of automation.

Elementary principle of numerical control of machine tools.

Chapter VII : Acceptance tests for machine tools.  

Recommended Books:

1. Principles of machine tools, Vol I & II, by G C Sen and A Bhattacharyya.

2. Design of machine tools by S K Basu

3. Design of machine tools by S K Basu and D K Pal

4. Production Technology, Vol II, by Dr. O P Khanna

ME 780 * (4) : NON-CONVENTIONAL ENERGY SYSTEMS (4-2-0)

Theory – 100

Sessional – 75

1. Different forms of non-conventional energy sources : Solar, Bio-gas , wind, tidal, geothermal etc.

2. Basic bio-conversion mechanism: Source of waste, simple digesters; composition and calorific value of biogas, Bio-mass as a source of energy, energy plantation, production of fuel from wood, agricultural and municipal solid and animal wastes, sludge and waste water, bio-gas generation and utilization.

3. Solar Option: Energy from sun – availability of solar radiation, technique of collection, storage and utilization; Types of solar collectors; selective surfaces; solar thermal processes – heating, cooling, drying, power generation etc. Thermoelectric conversion and thermal storage. Introduction to photoelectric conversion.

4. Wind and tidal energy generation: Special characteristics, turbine parameters, optimum operation, electric powergeneration from wind/tidal energy; Types of wind mills, Elementary design principles, Principle of ocean thermal energy conversion; Power plant based on OTEC.

5. Geothermal Energy: System. Extent of available resources. Heat transport in geothermal systems. Hot springs and steam injections.

6.      The Nuclear options: Fission, fusion technology fundamentals. Thermal and fast reactors. State of art Breeder reactors, prospect and limitations, economics. Fusion energy – controlled fusion of H₂, He etc. Energy release rate, future possibilities.

7. Direct conversion methods: Thermo-ions, MHD, electrochemical devices, fuel cells etc. Intrigated energy packages using solar, biomass, wind etc.

8. Comparative study of non-conventional energy source, cost consideration and economic.

 Books:

1. Waste water Engineering - by MetCaff, Eddy – McGrow Hills

2. Solar Energy - by SP Sukhatme – TMG

3. Solar Energy Utilization - Duffie & Beckman – Wiley Int. Ltd.