(DME 311) - Anucde · consisting of bending moment 10KN-m and a torsional moment 30KN-m. Determine...

(DME 311)

B.Tech. DEGREE EXAMINATION, DECEMBER 2010.

(Examination at the end of Third Year)

Mechanical Engineering

Paper I — OPERATIONS RESEARCH

Time : Three hours Maximum : 75 marks

All questions carry equal marks.

Answer Question No. 1 compulsorily. Answer ONE question from each Unit.

1. (a) What is operations research?

(b) Define Infeasible solution.

(c) Define Basic Solution.

(d) Define Optimum Basic Solution.

(e) Explain west corner method.

(f) What is unbalanced transportation matrix?

(g) What is network diagram?

(h) What is CPM?

(i) Define Independent float.

(j) What is Burst Event?

(k) What is an activity?

(l) Define successor activity.

(m) Define Mas Mini principal.

(n) What in Dynamic Programming?

(o) Define scheduling.

UNIT I

2. (a) Explain Applications of LPP.

(b) Solve the following LPP by Graphical method

Maximize yxZ 4030

subject to the constraints

.0,

000,913625000,00,13650

yxyxyx

Or

(DME 311) 2

3. Solve the following problems by Simplex method

Maximize 321 7198 xxxZ

subject to

0,,

5033

2543

321

321

321

xxx

xxx

xxx

UNIT II

4. Find the initial Basic Feasible solution by using Vogel’s Approximation Method (VAM) with cost Rs. 86

Destination

D1 D2 D3 D4 Supply

Source O1 1 2 –2 3 70

O2 2 4 0 1 38

O3 1 2 –2 5 32

Demand 40 28 30 32

Or

5. A methods Engineer wants to assign four new methods to three work centres. The assignment of the new methods will increase production and they are given below. If only one method can be assigned to a work centre, Determine the optimum assignment

Increase in production (unit)

Work Centers

A B C

Methods 1 10 7 8

2 8 9 7

3 7 12 6

4 10 10 8

UNIT III

6. With neat sketches explain the following

(a) Rules for drawing network diagram

(b) Common errors in drawing networks.

Or

7. A project schedule has the following characteristics

(DME 311) 3

Activity Time 1-2 2 1-4 2 1-7 1 2-3 4 3-6 1 4-5 5 4-8 8 5-6 4 6-9 3

(a) Construct the PERT network and find critical path and time duration of project.

(b) Activity 2-3, 4-5, 6-9 each requires one unit of the same key equipment to complete it. Do you think availability of one unit of the equipment in the organization is sufficient for completing the project without delay it? If so what is the schedule of these activity?

UNIT IV

8. (a) What are the characteristics of game theory

(b) Solve the following game by LP.

B1 B2 B3

A1 3 –1 –3

A2 –2 4 –1

A3 –5 –6 2

Or

9. (a) Explain the characteristics of Dynamic programming.

(b) Explain the advantages and limitations of DP by LP.

————————

(DME 312)




Paper II — DESIGN OF MACHINE ELEMENTS


Answer Question No. 1 compulsorily. (15 marks)

Answer ONE question from each Unit. (4 15 = 60)

1. (a) Explain briefly the general procedure in machine design. (2)

(b) What are the different mechanical properties of metals used in machine design? (2)

(c) Define factor of safety and its importance in machine design. (2)

(d) What are the various factors influence the endurance limit of a material? (2)

(e) Explain self locking screws. (2)

(f) Derive an expression when the circular fillet weld subjected to torsion. (2)

(g) Write briefly design procedure of knuckle joint. (3)

UNIT I

2. (a) Explain the different types of machine design.

(b) A cylindrical shaft made of steel of yield strength 700 Mpa is subjected to static loads

consisting of bending moment 10KN-m and a torsional moment 30KN-m. Determine

the diameter of the shaft using two different theories of failure, and assuming a factor

of safety of 2. Take E = 210 Gpa and Poisson’s = 0.25.

Or

3. (a) Explain the general considerations in Machine design.

(b) Explain the following theories of failures

(i) Maximum shear stress theory

(ii) Maximum principal strain theory.

UNIT II

(DME 312) 2

4. (a) Explain the Goodman method for combination of stress.

(b) A 50 mm diameter shaft is made from carbon steel having ultimate tensile strength of 630 Mpa. It is subjected to a torque which fluctuates between 2000 N-M to –800 N-M. Using Soderberg method, calculate the factor of safety. Assume suitable values for any other data needed.

Or

5. (a) Explain the efficiency of square threaded screws and derive an expression for maximum efficiency of a square threaded screw.

(b) An electric motor driven power screw moves a nut in a horizontal plane against a force of 75 KN at a speed of 300 mm/min. The screw has a single square thread of 6 mm pitch on a major diameter of 40 mm. The coefficient of friction at screw threads is 0.1. Estimate power of the motor.

UNIT III

6. Two plates of 10 mm thickness each are to be joined by means of a single riveted double strap butt joint. Determine the rivit diameter, rivit pitch, strap thickness and efficiency of the joint. Take the working stresses in tension and shearing as 80 Mpa and 60 Mpa respectively.

Or

7. A rectangular steel plate is welded as a cantilever to a vertical column and supports a single concentrated load P, as shown in fig. Determine the weld size of the shear stress in the same is not to exceed 140 Mpa.

(DME 312) 3

UNIT IV

8. Design a Cotter joint to support a load varying from 30 KN in compression to 30KN is tension. The material used is carbon steel for which the following allowable stresses may be used. The load is applied statistically.

Or

9. Design a knuckle joint to connect two mild steel bars under a tensile load of 25 KN. The allowable stresses are 65 MPa in tension, 50 Mpa in shear and 83 Mpa in crushing.

————————

(DME 313)



Mechanical Engineering.

Paper III — MACHINE DYNAMICS


Answer Question No. 1 Compulsorily.

Answer ONE question from each Unit.


1. (a) Explain D'Alembert's principle. (2)

(b) Discuss dynamic balancing. (2)

(c) Types of dynamometers. (2)

(d) What is meant by Gyroscopic Torque? (2)

(e) Types of Governors. (2)

(f) Sketch the four – link mechanism. (2)

(g) Distinguish between flywheel and governor. (3)

(DME 313) 2

UNIT I

2. The crank and the connecting rod of an engine are 125 mm and 500 mm respectively. The connecting rod is of mass of 60 kg and its centre of gravity is 275 mm from the cross head pin centre, the radius of gyration about centre of gravity being 150 mm. If the engine speed is 600 rpm, for a crank position of 45 from the inner dead centre, determine, using klien's or any other construction.

(a) The acceleration of the piston

(b) The magnitude, position and direction of inertia force due to the mass of the connecting rod.

Or

3. The crank and connecting rod of a steam engine are 300 mm and 1500 mm in length. The crank rotates at 180 rpm clockwise. Determine the velocity and acceleration of the piston when the crank is at 40 from inner dead centre position. Also, determine the position of the crank for zero acceleration of the piston.

UNIT II

4. A twin cylinder v-engine has the cylinders set at an angle of 40 with the both pistons connected to a single crank. The crank radius is 60 mm and connecting rods are 300 mm long. The reciprocating mass is 1 kg per line and the total

(DME 313) 3

rotating mass is equivalent to 1.5 kg at crank radius. A balance mass is filled opposite to the crank equivalent to 1.8 kg at a radius of 80 mm. Determine for an engine speed of 900 rpm, the maximum and minimum values of the primary and secondary forces due to inertia of the reciprocating and rotating masses.

Or

5. A shaft carries four masses A, B, C and D at the extremities of arms of radii 20, 24, 30 and 24 cm respectively. The planes containing B, C and D are 30 cm, 48 cm and 72 cm respectively from the plane containing A. A = 20 kg, B = 50 kg, C = 30 Kg and D = 15 kg. Determine the necessary alternation to B and the angular positions of all the masses so that shaft may be incomplete balance.

UNIT III

6. The engine and the propeller of an aeroplane weighs 5 KN and the radius of gyration is 500 mm. The propeller rotates at 3000 rpm in clockwise direction looking from the rear of the aeroplane makes quarter of a circle of radius 100 m toward left hand side while flying at 240 km per hour. What gyroscopic couple will act on the aeroplane frame and what will be its effect?

Or

(DME 313) 4

7. In a prony brake dynamometer. The leverage is 750 mm and radius of the brake drum is 250 mm. If the engine is developing 37.3 kw power at 300 rpm. What would be the spring balance reading?

UNIT IV

8. A porter governor has equal link, each 250 mm long, pivoted at the axis; each ball is of mass 4 kg and the mass of central load is 15 kg. The governor begins to lift when the ball radius is 150 mm. It has a maximum speed at a radius of 200 mm. Determine the maximum speed; the range of speed; the sleeve left; the governor effort and the power of the governor.

Or

9. What is the function of a governor? Explain with a neat sketch the construction and working of a watt governor.

———————

WS 17

(DME 314)




Paper IV — HYDRAULIC MACHINES


Answer question No. 1 compulsorily.

(5 3 = 15)


(4 15 = 60)

UNIT I

1. (a) Write about forces exerted by fluid jet on a stationary flat plate.

(b) Classification of Turbines.

(c) What is difference between propeller and Kaplan Turbine?

(d) What is the principle of pump?

(e) Define Buckingham’s pi theorem.

UNIT II

2. A jet 200mm diameter moving of a velocity of 20m per second impinges normally on a series of flat vanes mounted over a wheel. If the velocity of the vanes is 8m per second, find

(DME 314)

2

WS 17

(a) The force exerted by the jet on the wheel.

(b) The work done by the jet on the wheel per second.

(c) The hydraulic efficiency.

Or

3. A boat driven by jet propulsion draws water through orifices amidship at 0.65 cumec. The water is discharged through orifices of area 0.05 metre 2 at the stern. Find the propelling force on the boat when it moves at 6m/sec.

UNIT III

4. The approach channel conveying water to an overshot water wheel is 1.5 meters wide the depth of flow being 0.2metre.The velocity of water in the channel is 1.75m per second. If the depth of the water fall is 18 metres find the power developed assuming an overall efficiency of 65%.

Or

5. The following results were obtained in test on a pelton wheel turbine:

Head at the base of the nozzle = 34.5m

Discharge of the nozzle = 0.2 cumec

Area of the jet = 280cm

Shaft power develop = 55.2 kw

(DME 314)

3

WS 17

kw3.30windageandResistance

mechanicalinabsorbedPower

Find (a) Power lost in the nozzle

(b) Power lost in the runner.

UNIT IV

6. A centrifugal fan has to deliver 4.25 cumec of air when running at 750 rpm. The diameter of the impeller at intel is 530mm and at outlet is 760mm. It may be assumed that the air enters radially with a speed of 15.25m/sec. The vanes are set

backwards at out lets at o70 at the tangent and the width at out let is 101.5mm. The volute casing gives a 30 percent recovery of the out let velocity head. The losses in the impeller may be taken as equivalent to 25 percent of the outlet velocity

head. The sp. wt of air is 12.25 3N/m and blade thickness effects may be neglected. Determine the manometric efficiency, the power required and the pressure at discharge.

Or

(DME 314)

4

WS 17

7. A single acting reciprocating pump has attunger diameter of 100mm and a stroke of 20mm. The suction pipe is 80mm in diameter and 6m long. The pump is situated at a height of 3m above the sump water level. If the pump runs at 30rpm. calculate the absolute pressure head in the cylinder at the beginning of the stroke. Take atmospheric pressure head = 10.30 metres of water.

UNIT V

8. Assuming that the viscous force F exerted by a fluid on a sphere of diameter D depends on the viscosity , mass density of fluid P, and the velocity of sphere ‘V’ obtain an expression for the viscous force.

Or

9. Derive on the basis of dimensional Analysis suitable parameters to represent the thrust developed by a probelles. Assume that the thrust P depends upon the angular velocity ‘w’ speed of advance ‘V’ diameter ‘D’ dynamic viscosity , mass density P and elasticity of the fluid medium which can be denoted by the speed of the sound in the medium C.

——————

(DME 315)




Paper V — I.C. ENGINES AND GAS TURBINES


Answer Question No. 1 compulsorily. (1 15 = 15)


1. (a) Classification of I.C. engines.

(b) Define value and port.

(c) What is the functions of carburettor?

(d) Fuel pump.

(e) Heat balance in I.C. Engines.

(f) Types of fuels.

(g) Octane number.

(h) Applications of centrifugal compressor.

(i) Stalling in I.C. Engine.

(j) Basic-closed cycle for gas turbine is implemented in which cycle.

(k) Compare thermal efficiency of Gas Turbine plant to Diesel Engine plant.

(l) Overall thermal efficiency of Jet engine.

(m) Distinguish between spark ignition engine compression Ignition Engine.

(n) Mean effective pressure.

(o) Define Detonation.

UNIT I

2. (a) Explain the basic engine nomenclature.

(b) With the help of neat sketch, explain the construction and working principle of SI engine (2 stroke).

Or

3. Sketch and explain the construction and working of simple carburettor.

(DME 315) 2

UNIT II

4. In a constant speed compression ignition engine operating on four-stroke cycle and fitted with band brake, the following observations were taken.

Brake wheel diameter = 60 cm.

Band thickness = 5 mm

Speed = 450 rpm.

Load on band = 210 N

Spring balance reading = 30 N

Area of indictor diagram = 4.15 m2

Length of indicator diagram = 6.25 cm

Spring No. 11 i.e. = 11 bar/cm.

Bore = 10 cm

Stroke = 15 cm.

Specific fuel compression = 0.3 kg/kw-hr.

Heating value of fuel = 41800 kJ/kg.

Determine the brake power, indicated power, mechanical efficiency, the indicated thermal efficiency and the brake thermal efficiency.

Or

5. A 4-cylinder engine running at 1200 rpm gave 18.6 kW. The average torque when one cylinder was cut out was 105 N-m. Determine the indicated thermal efficiency, if the calorific value of the fuel is 41800 kJ/kg and the engine uses 0.34 kg of petrol per kw-hr.

UNIT III

6. Explain what is pre-ignition in S.I. Engine. Does it cause detonation in these engines?

Or

7. An axial flow compressor comprises a number of similar slages with equal work done/stage land the velocity of flow is uniform throughout the compressor. The following are the data :

Overall stagnation pressure ratio = 3.5

Stagnation inlet temperature = 60°C

Relative air angle at rotor inlet = 130°C

Relative air angle at rotor out let = 100°C

Blade velocity = 185 m/sec

Degree of reaction = 0.5

Overall stagnation adiabatic efficiency = 0.87

The data refer to mean blade height and the measurement of angle is done in the same sense from the velocity diagram. Calculate :

(DME 315) 3

(a) Stagnation of outlet temp.

(b) Number of stages.

UNIT IV

8. In the closed cycle gas turbine the following data apply : working substance = Air, regarded as a simple gas with 1PC kJ/kg and 4.1r

Ambient tempt = 27°C

Top temp = 823°C

Pressure at comp inlet = 1 bar

Pressure ratio = 4

Comp efficiency = 80%

Turbine efficiency = 85%

Heating value of fuel = 41800 kJ/kg

Find the following :

(a) Compressor work kJ/kg

(b) Turbine work kJ/kg

(c) Thermal efficiency

(d) Heat supplied kJ/kg

(e) Network kJ/kg

(f) Air rate per shaft kW-hr

(g) Airfuel ratio

Or

9. In a gas turbine plant, air is compressed from 1 bar at 15°C through a pressure ratio of 4 : 1. It is then heated to 650°C in a combustion chamber and expended sack at atmospheric pressure of 1 bar in a turbine. Calculate the cycle efficiency and the work ratio of a perfect heat exchanger is used. The isentropic effectiveness at the turbine and compressor are 80 and 85% respectively.

–––––––––––––––

(DME 316)




Paper VI —METAL CUTTING & MACHINE TOOLS


Answer Question No. 1 Compulsory. (1 15 = 15)


1. Write a short note on :

(a) Principle of Thread cutting

(b) Lathe accessories

(c) Types of planers

(d) Types of shapers

(e) Specification of milling machine

(f) Types of cutting fluids

(g) Types of tool geometry

(h) Advantages of universal milling m/c

(i) Define Tool life

(DME 316) 2

(j) Up milling Vs Down milling

(k) Built up Edge

(l) Types of cutting tools.

(m) Calculation of different cutting forces

(n) Distinguish Honing and Lapping

(o) Dressing of Grinding wheels.

UNIT I

2. (a) Define a machine tool. Discuss the general requirements of design of machine tool.

(b) Explain the Primary and Auxiliary motions of machine tool.

(c) Describe the working of apron and half – nut in Lathe.

Or

3. (a) Sketch and Explain the five main parts of a lathe.

(b) Calculate suitable gear trains for cutting 10 mm pitch, 3 start on a lathe with a lead screw having 6.25 mm pitch.

Assuming that the available gears are

20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110.

(DME 316) 3

UNIT II

4. (a) What are the classifications of Drilling machine? Explain any five drilling machine operations.

(b) Explain the feed and machine time in drilling.

(c) Find the time required for drilling a 18 mm hole in a work piece having thickness 50 mm. Assume cutting speed 12m/min and feed 0.2 mm/rev. Neglect the length of approach.

Or

5. (a) Sketch and Explain quick return mechanism of a shaper.

(b) What are the various factors to be considered in selection of grinding wheel? Discuss each in detail.

UNIT III

6. (a) Sketch the elements of a high speed steel milling cutter.

(b) Name the various milling attachment.

(c) Difference between

(i) Up milling and down milling.

(ii) Bed type and planer type milling machine.

Or

(DME 316) 4

7. (a) Sketch and explain the principle of differential indexing.

(b) A certain component can be milled with either a slab mill of 90 mm dia, or a 150 mm diameter face mill. Each cutter has 16 teeth and the cutting speed is 20 m/min. If the feed for the slab mill is 0.15 mm per tooth and for the face mill 0.25 mm per tooth. What is the rate of feed for each other?

UNIT IV

8. (a) How do you classify the cutting tools? What is the difference between orthogonal and oblique cutting?

(b) What is the mechanism of chip formation with neat sketch? Explain the nomenclature of signal point cutting tool and their angles.

Or

9. (a) What are the types of Tool wears? Explain.

(b) What are the requirements of tool material? Discuss

(i) High speed steels

(ii) Diamond Tools.

———————

(DME 321)




Paper I — OPERATIONS MANAGEMENT


Answer any FIVE of the following.


1. (a) Batch production.

(b) Method of least squares.

(c) Aggregate planning.

(d) XYZ analysis.

(e) Safety stock.

(f) Doubling sampling plan.

2. State the features of job order production.

3. What are different methods of aggregate planning?

4. Explain the functions of materials management.

(DME 321) 2

5. Discuss the tolerance limits for a process.

6. Describe the nature and significance of TQM.

7. Enumerate the formation of master scheduling.

8. What are the relevant costs in inventory management?

9. Describe the features of mass and flow production.

————————

(DME 322)




Paper II — DESIGN OF TRANSMISSION ELEMENTS


Answer Question No. 1 Compulsorily.



1. Answer in brief :

(a) Applications of split muff coupling.

(b) Types of Lubricautions.

(c) Selection of ball in Roller bearing.

(d) Advantages of chain drive over belt drive.

(e) List the terminology used in helical gears.

UNIT I

2. A transmission shaft supporting a spur gear B and pulley D. The shaft is mounted on two bearing A and D. The diameters of pulley and gear are 450 and 300 mm respectively. 20 kW power at 500 rpm is transmitted from the pulley to the gear 1P and 2P are the belt tensions in the tight and loose sides while tP and rP are tangential and radial components of the gear – tooth force. Assume 21 3PP and tQ PP tan 20. The gear and pulley are keyed to the

shaft. The material for the shaft is steel 50 4C ( utS = 700 and ytS = 460 2mmN ). Determine

the shaft diameter using ASME code if 1.5KK tb .

Or

3. A flexible coupling is used to transmit 15 kW power at 100 rpm. There are 6 pins and their pitch circle diameter is 200 mm. The length of pin in contact with the left hand flange, the gap between the two flanges and the length of bush in contact with the right hand flange are 23, 5 and 35 mm respectively. The permissible shear and bending stresses in the pin are 35 and 152 2mmN respectively. The permissible pressure for the rubber brush is 1 2mmN . Calculate

(a) pin diameter by shear consideration

(b) pin diameter by bending consideration

(c) outer diameter of the rubber brush.

(DME 322) 2

UNIT II

4. (a) Discuss selection of parameters for Journal bearing design.

(b) The following date is given for 360 hydrodynamic bearing :

Diameter of bearing = 50.02 mm, Journal diameter = 49.93 mm, bearing length = 50 mm, Journal speed = 1440 rpm, radial load = 8 kW, viscosity of the lubricant = 12 cp. The bearing is machined on lathe from bronze casting, while the steel journal is hardened and ground. The surface roughness values for honing and grinding are 0.8 and 0.4 microns. For thick film lubrication, the min film thickness should be 5 times of sum of surface roughness.

Calculate :

(i) permissible min-film thickness

(ii) the actual film thickness under operating conditions

(iii) power lost infriction.

Or

5. The developed view of a hydrostatic bearing is shown in fig (a) consider the flow in the direction shown by arrows and neglect the flow in the other direction and over corners. the pressure distribution is linear. The thrust load is 500 kN and the film thickness is 0.2 mm. The viscosity of the lubricant is 500 cp. Calculate the supply pressure and flow requirement.

UNIT III

6. (a) Write the procedure for selection of pulleys.

(b) The leather belt drive transmits 15 kW power. The centre distance between the pulleys is twice the diameter of the big pulley. Let the diameters be ‘d’ and ‘D’. Both runs at 1440 rpm and 480 rpm respectively. The belt should operate at a velocity of 20 m/s approximately and the stresses in the belt should not exceed 2.25 N/mm2. The density of leather is 0.95 gm/cc and the coefficient of friction is 0.35. The thickness of the belt is 5 mm.

(DME 322) 3

Calculate :

(i) the diameters of pulleys

(ii) the length and width of the belt

(iii) the belt tensions.

Or

7. A sample chain No. 08 B is used to transmit power from a transmission shaft running at 200 rpm to another shaft running at 100 rpm. There are 19 teeth on the driving sprocket wheel and the operation is smooth without any shocks. Calculate :

(a) the power transmitting capacity of the chain drive

(b) the chain velocity

(c) the chain tension and

(d) the factor of safety based on the breaking load.

UNIT IV

8. (a) Explain desirable properties of a gear material.

(b) A pair of spur gears with centre distance of 495 mm is used for a speed reduction of 4.5 : 1. The module is 6 mm. Calculate the number of teeth on the pinion and the gear.

Or

9. The following data is given for a pair of parallel helical gears made of steel :

Speed of pinion = 720 rpm, number of teeth on pinion = 35, number of teeth on gear = 70, centre distance = 285 mm normal module = 5 mm, face width = 50 mm, normal pressure

angle = 20, ultimate tensile strength = 450 2mmN surface hardness = 300 BHN, grade of

machining = Gr. 8, factory safety = 2, service factor = 1.25

Calculate :

(a) helix angle

(b) the beam strength

(c) the wear strength

(d) the dynamic load by Spotl’s equation

(e) the maximum static load that the gears can transmit

(f) the power transmitting capacity.

———————

(DME 323)




Paper III — MECHANICAL VIBRATIONS


Answer Question No. 1 compulsorily.



1. (a) What are the causes and effects of

vibrations?

(b) Explain the term logarithmic decrement as applied to damped vibrations.

(c) Explain the term whirling speed of a shaft.

(d) Define over damping.

(e) Discuss dynamic magnifier.

(DME 323) 2

UNIT I

2. (a) Explain different types of free vibrations.

(b) A cantilever shaft 50 mm diameter and 300 mm long has a disc of man 100 kg at its free end. The Young’s modulus for the shaft material is 200 GN/m2. Determine the frequency of longitudinal and transverse vibrations.

Or

3. A fly wheel is mounted on a vertical shaft as shown in fig. The both ends of the shaft are fixed and its diameter is 50 mm. The flywheel has a mars of 500 kg. Find the natural frequencies of longitudinal and transverse vibrations. Take

200E GN/m2.

(DME 323) 3

UNIT II

4. A shaft 1.5 m long, supported in flexible bearings at the ends carries two wheels each of 50 kg mars. One wheel is situated at the centre of the shaft and the other at a distance of 375 mm from the centre towards left. The shaft is hollow of external diameter 75 mm and internal diameter 40 mm. The density of the shaft material is 7700 kg/m3 and its modulus of elasticity is 200 GN/m2. Find the lowest whirling speed of the shaft, taking into account the mars of the shaft.

Or 5. The following data are given for a vibratory

system with viscous damping : Mars = 2.5 kg, spring constant = 3 N/mm and the amplitude a decreases to 0.25 of the initial value after five consecutive cycles. Determine the damping coefficient of the damper in the system.

UNIT III

6. A mars of 500 kg is mounted on supports having a total stiffness of 100 kN/m and which provides viscous damping, the damping ratio being 0.4. The mars is constrained to move vertically and is subjected to a vertical disturbing force of the type

wtF cos . Determine the frequency at which resonance will occur and the max-allowable value of F , if the amplitude is restricted to 5 mm.

Or

(DME 323) 4

7. Calculate the whilling speed of a shaft 20 mm diameter and 0.6 m long carrying a mars of 1 kg at its mid point. The density of the shaft material is 40 mg/m3 and Young’s modulus is 200 GN/m2. Assume the shaft to be freely supported.

UNIT IV

8. Determine the natural frequency of free longitudinal vibration using equilibrium method.

Or

9. Determine the natural frequency using Rayleigh method.

–––––––––––––––

(DME 324)




Paper IV — BASIC ELECTRONICS AND MICROPROCESSORS


Answer Question No. 1 compulsorily. (1 15 = 15)


1. (a) Draw the VI characteristics of a PN junction diode both in forward and reverse bias.

(b) Define PIV of a rectifier.

(c) What are the applications of zener diode?

(d) Convert 10)35( to BCD number.

(e) What are the applications of flip flop?

(f) Define Dynamic RAM.

(g) What is meant by EEPROM?

(h) Draw any one universal gate.

(DME 324) 2

(i) Convert 16)346A( to decimal number.

(j) What are the flags available in 8085?

(k) Why do you use three RC sections in RC oscillator?

(l) Why is quartz crystal commonly used in crystal oscillators?

(m) What are the applications of multiplexers?

(n) What does the instruction MEWR perform in 8085?

(o) Define ALV.

UNIT I

2. (a) Draw the UJT characteristics and explain its working.

(b) Explain PN junction in equilibrium with no voltage applied, under forward bias and reverse bias conditions.

Or

3. (a) With neat diagrams explain the characteristics of zener diode and its applications.

(b) Explain the working of a half wave rectifier without filter with a circuit diagram.

(DME 324) 3

UNIT II

4. (a) What are the advantages of oscillators? Discuss the circuit operation of a Wein bridge oscillator.

(b) List the applications of opamp and draw the circuit of opamp as comparator.

Or

5. (a) Explain the action of a multivibrator in monostable mode.

(b) Discuss the circuit operation of a RC phase shift oscillator with a neat circuit diagram.

UNIT III

6. (a) Solve for 81610 )()()90925( .

(b) Draw the half adder circuit and truth table and explain its function.

Or

7. (a) Write the excitation table for SR flip flop and explain its operation.

(b) With a neat diagram explain the operation of multiplexer.

(DME 324) 4

UNIT IV

8. (a) Write an assembly language program of 8085 to arrange a series of numbers in descending order.

(b) Explain the following instructions of 8085 :

RAR, MVI, PCHL, XCHG and RAL.

Or

9. (a) Discuss the function of ALV of 8085.

(b) Write an assembly language program of 8085 to find the largest number of given data (10 numbers).

———————–––

(DME 325)




Paper V — HEAT TRANSFER



Answer question No.1 compulsorily.

(7 2 = 14)


(4 14 = 56)

1. (a) Define critical thickness of insulation for a cylinder.

(b) Define overall heat transfer coefficient for a composite slab.

(c) Explain why fixs are used? What are the commonly used types of fixs?

(d) Explain why fixs are generally used on the gas side in a gas-to-liquid heat exchange.

(e) Define NTV and effectiveness of a heat exchange.

(f) Define hydradynamic used thermal boundary layers.

(g) Distinguish between black body and grey body.

UNIT I

2. (a) Derive the expression for the critical radius of insulation for a sphere. (6)

(b) A stainless steel tube ( K = 19 W/mk), 2 cm ID and 4 cm OD is covered with a 4 cm

layer of asbestos insulation (K = 0.21 W/mk). If the steady state heat loss per metre

length of the tube is 750 W/m, and the outside surface temperature is limited to 50ºC,

what is the temperature of the inside wall of the tube? (8)

Or

(DME 325) 2

3. (a) Derive an expression for the temperature distribution in a solid cylinder of radius ‘R’

with internal heat generation. (6)

(b) Calculate the rate of heat loss from a rectangular fin of length 3 cm attached to a plane

wall. The thickness of the fix is 2 mm and its breadth is 20 cm. The convective heat

transfer coefficient from the surface of the fix to the outside air is 20 W/m2 ºC. The

ambient temperature is 30ºC and the temperature at the base of the fix is 100ºC.

Assume that the heat loss from the tip of the fin is negligible. (8)

UNIT II

4. (a) What is meant by lumped capacity? What are the physical assumptions necessary for a

lumped – Capacity unsteady – State analysis to apply? (4)

(b) A 5 cm diameter copper sphere is initially at a uniform temperature of 200ºC. If is

suddenly exposed to an environment at 20ºC having a heat transfer coefficients of 28

W/m2 ºC. Using the lumped capacity analysis, calculate the time necessary for the

sphere to reach 90ºC. (10)

Or

5. (a) Describe the relation between fluid friction and heat transfer. (6)

(b) Air A 1 atm and 35ºC flows across a 5 cm diameter cylinder at a velocity of 50 m/sec.

The cylinder or surface is maintained at 150ºC. Calculate the heat loss per unit length

of the cylinder. (8)

UNIT III

6. (a) Show that T1 for an ideal gas having the equation of state P = PRT. (4)

(b) A horizontal pipe 8.0 cm diameter is located in a room where atmospheric air is at 25ºC.

The surface temperature of the pipe is 15 m long. How much heat lost from the pipe per

unit length? (10)

Or

7. (a) Derive an expression for the effectiveness of a parallel flow heat exchanger. (7)

(b) A counter flow double pipe heat exchanger in to be used to heat 0.7 Kg/sec of water

from 35ºC to 90ºC with an oil flow of 0.9 kg/sec. The oil has a specific heat of 2.1 kJ/Kg

K. and enters the heat exchanger at a temperature of 175ºC. The overall heat transfer

coefficient is 425 W/m2 K. Calculate the area of the heat exchanger and its

effectiveness. (7)

(DME 325) 3

UNIT IV

8. (a) Define irradiation and radiosity. (4)

(b) Two parallel concentric disks have 1d =100 cm, 2d = 5 cm and are spaced at 10 cm

apart. Determine 12F and 21F . (10)

Or

9. The large parallel planes having emissivities of 0.3 and 0.5 are maintained at temperatures of 900 K and 400 K respectively. A radiation shield having an emissivity of 0.05 on both sides is placed between the two planes. Calculate

(a) The heat transfer rate per unit area if the shield were not present

(b) The heat transfer rate per unit area with the shield present

(c) The temperature of the shield. (14)

——————

(DME 326)




Paper VI — ENGINEERING METROLOGY


Answer Question No. 1 compulsorily.



1. (a) What is standards of length?

(b) What is shaft basis system?

(c) Define tolerance.

(d) Application of sine bar.

(e) Functions of clamping devices.

(f) Gear hobbing.

(g) Applications of bore guages.

(h) List the terminology used in surface finish.

(i) Applications of CMM.

(DME 326) 2

(j) List different types of Alignment Tests on Lathe.

(k) Static versus dynamic alignment tests.

(l) Best size wire.

(m) Use of V-Block

(n) Applications of fixture.

(o) Spirit level.

UNIT I

2. (a) Define limit. Explain in detail about different types of limits and fits.

(b) Discuss about selective assembly system in detail.

Or

3. (a) Write Taylor’s principle of limit gauging.

(b) On a limit system the following limits are specified between a shaft and hole.

Shaft 50 0.003 mm. Hole + 0.003 mm – 0.000 mm.

Find :

(i) Basic size

(ii) Shaft and hole tolerance

(iii) Max-clearance

(iv) Min clearance.

(DME 326) 3

UNIT II

4. (a) Explain design considerations in Tigs and fixtures.

(b) Explain principles and methods of Bevel gear generation.

Or

5. (a) Explain the principle of six point location and discuss about locating pins.

(b) Discuss gear hobbing. List out the applications and advantages of gear hobbing.

UNIT III

6. (a) Sketch and explain the measurement of effective diameter of thread using 2 wire method and derive the expression.

(b) Explain the construction and working principle of sigma comparator.

Or

7. (a) With the help of neat sketch explain the construction working and applications of Toolmaker’s microscope.

(b) Explain the straightness Testing using straight edge (wedge method).

(DME 326) 4

UNIT IV

8. (a) With a neat diagram explain Tomlinson surface meter in detail.

(b) Various alignment tests on milling machine in detail.

Or

9. (a) With the help of neat sketch explain the construction and working of Talysur Hobson Talysurf.

(b) Discuss various alignment tests on drilling machine with suitable sketches.

–––––––––––––––

(DME 311) - Anucde · consisting of bending moment 10KN-m and a torsional moment 30KN-m. Determine...

Documents

Transcript of (DME 311) - Anucde · consisting of bending moment 10KN-m and a torsional moment 30KN-m. Determine...