6th Semester Mechanical Engineering (Dec-2015; Jan-2016) Question Papers

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Sixth Semester B.E. Degree Exam , Dec.20l5lJan.20l6
Heat and Mass Transfer
€ Time: 3 hrs. Max. Marks:tffi
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* Note: l. Answer any FIVE full questions, selecting r "l'*
H atleast TWO questions from each part.
R 2. (Ise of heat iansfer data hand book ancl steam tuble$ ,
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S,8 PART - A
gE I a. Derive the general 3 - D Heat conduction equation in Cartesian coordinate system and
E ff hence obtain Laplace and Poisson equations. (10 Marks)
"*ti b. The Interior of a Refrigerator having inside dimensions of 0.5 x 0.5m base area and 01 mtr
:E E height is to be maintained at 60C. ihe walls of the Refrigerator are constructed of 2 milddt
iJ ,p steel sheets, thre^e (3mm) thick. [K : 46.5 Wm uC]
with a 50mm of glass wool insulation
E H [K: 0.046Wim 0C1
between them. If the Average Hegt transfer coefficients at the inner and
E
.E outer surfaces are ll.6Wlm2 0C
and 14.5W1m2
0C
resoectively.
A i Calculate : i) The rate at which the heat must be removed from the lnterior to maintain the
* ; specified temperature in the kitchen at 250C and ii) The temperature on the outer surface
g * of the metal sheet. (10 Marks)
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I E *::5f-m;:,;'74 r*=*,,p/;.r
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; ! 2 a. Derive an expression for critical thickness of insulation for a sphere. (08 Marks)
H E b. A motor body is 360mm in diameter (OD) and 240mm long. It's surface temperature should
F E not exceed-5$"C when dissipating 340 watts. Longitudinal fins of l5mm thickness and
e f 40mm t6:ffi"-are produced. The convection coefficient is 40W/m2 oC. Determine the
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40mm fuiffi"are produced. The convection coefficient is 40W/m2 oC. Determine the
numbeq{fl'fins required. Assume, the atmospheric temperature is 300C for a finite fin.
[Figffi(a)]. (I2lvlarks)
qlu.fu,F --'".
$ ;. numDe(qP Ins requfied. Assume, the amospheflc temperature rs 30"U tor a trrute trn.
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"E&F*' 3 a. Show that the temperature distribution under Lumped analysis is given by,
Fr
S' L& = s-B;Fo , where Ti : Initial temperature , Tu : Ambient temperature. (10 Marks)
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b. A 15mm diameter Mild Steel Sphere (K:42Wlm0c; is e*posed to cooling air flow at200C
resulting in the convective coefficient 'h' : 720 Wlm2
0C.
Determine the following :
i) Time required to cool the sphere from 5500C to 900C.
ii) Instantaneous heat transfer rate 2 minutes after start of cooling.
iii) Total energy transferred from the sphere during the first 2 minutes.
For Mild steel take : p : 7850 kglm3, Cp: 475 J/kg
0C
and u : 0.045 m'lhr. (10 Marks)
I of2

2. {fiiii
a.
b.
IOME63
Using Buckingham's fi - theorem, obtain the relationship between various dimensionless
numbers (N, : 0 GJ (G.) for free convection heat transfer. (08 Marks)
Air at 200C and at a pressure of 1 bar is flowing over a flat plate at a velocity of 3mlsec if
the plate is 280 mm wide and 560C. Calculate the following quantities at x:280mm, given
that the properties of air at bulk mean temperature : 380C are : p : 1.1374 kglr43,
K: O.O2732WlmoC , Co: 1.005 kJikg
0K, y: t6.768 x i0-6 m'lsec , P,:0.7. ffi
i) Boundary layer thickness ii) Thickness of boundary layer iii) Local copp{f,Se
heat transfer coefficient iv) Average convective heat transfer coefficient @*Wgte of
heat transfer by convection vi) Total drag force on the plate. __.ft*(i2fivlark0
PART-B , )*
Explain the significance of i) Reynold's number ii) Prandtl n"rlQt$ rii) Nusselt
number iv) Stanton number. { (10 Marks)
A refrigerated truck is moving on a highway atg}krn/hr in a deseffiffi where the ambient
air temperature is 500C. The body of the truck is a ^rfQt$rifular box measuring
1Omh (length) x 4m(width) x 3m(height). Assume that the podhflYry hyer on the four walls
is turbulent. The heat transfer takes place only from the fouq 3urfaces and the wall surfaces
of the truck is maintained at 100C. Neglecting heat tianSfer from front and back and
assuming flow to be parallel to 10m long side, calcuiate : i) A heat lost from the four
surfaces ii) The power required to overcome the r0sistance acting on the four surfaces.
The properties of air (at tr: 3-00q) are: p =_ f.i65kg/m3 , Cp: 1.005 kJlkg 0C
,
K: 0.02673Wm
oC
, y : 16 x 10-6 m'ls , n5,U.7bt (10 Marks)
a- Derive an expression for LMTD o$ounter flow heat exchanger. State the assumptions
made.
^ r*q* 3 (10 Marks)
b. 8000 kglhr of air at 1000C is cB#&Yypassing it through a single pass cross flow heat
exchanger. To what temperaturerip tde air cooled, if water entering u 15^oq flows through tbe
tubes unmixed atthe rate of 7500 kglhr. Take, U:500kJ/trr-m'0C , A:20m2,
C, of air: 1kJ/kg
0C
, Cr,,ofwater : 4.ZtltUg0C. ;rig.qO1a;1 (10 Marks)
,
.,,,,'u, frrl =1gja
..1
.t
d,lll'
Fig'Q6(a) l,'= ?
a. Define i) Pool boiling ii) Forced convection boiling iiD Sub cooled iv) Local
b'oiling iv) Saturated boiling. (08 Marks)
b. Explain Fick's law of diffusion. (04 Marks)
c. A vertical tube (Taking Experimental value) of 60mm OD and 1.2mtr long is exposed to
steam^at atmospheric pressure. The outer surface of the tube is maintained at a temperature
of 500C by circulating cold water through the tubes. Calculate i) Rate of heat transfer to
the coolant ii) The rate of condensation of steam. Assuming the condensation film is
Laminor and TPP of water at 750C are: pL : 975 kg/m3, W, : ZIS x 10-6 N-S/m2 ,
K : 0.67Wm0 C. The properties of saturated vapor i*, : 1000C , p, : 0.596 kg/m3,
hs:2257Wlkg- (08 Marks)
For a Black body enclosed in a hemispherical space, show that emissive power of Black
body is n times the Intensity of Radiation. (08 Marks)
State and explain i) Kircho{f s law ii) Planck's law iii) Wein's displacement law
iv) Lambert's cosine law. (08 Marks)
Explain briefly the concept of a Blackbody. (04 Marks)
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10M862
(10 Marks)
(12 Marks)
Sixth Semester B.E. Degree Examination, Dec.2015 I Jan.20l6
Design of Machine Elements - ll
Note: 1. Answer FIVE full questions, selecting
at least TIUO questions from each part.d
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2. Use of data hand bookpermitted.
3. Missing data, if any, may be suitably assumed.
PART _ A
A ring is made from a 75mm diameter bar. The inside diametercf the ring is 100mm. For
the load shown in figure Ql(a), Calculate the maximum shearqtress in the bar and specify
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An engine's chest ipC$r.?.a by a flat rectangular head of 200mm x 300mm dimensions.An engme's cnest l**qplvereo Dy a llat rectangular head ot Zuumm x JUUmm dlmenslons.
The plate is maderdg*.y cast iron FG150 with ultimate stress of the material is 150N/mm2,
supported at *thq,.edses and subjected to a uniform pressure of 1.5N/mm2. Determine the
thickness of3ffe,hbad for a factor of safety 5. (10 Marks)
.r3"
A 'V' b$lPis to be arranged between two shafts whose centers are 3000mm. The driving
its location.
Safe working tensile stress * 2.1 N/mm2
Coefficient of friction -0.27
Groove angle of pulley - 40"
Also find the initial tension required in each belt.
A 20mm 8 x 19 steel wire rope is used with a hoisting drum of lm diameter to lift a load of
201N. The depth of mine is 800m and the acceleration is 3mlsec2. Determine the numbei of" - -" "
ropes required using a factor of safety 5. Neglect weight of skip. tog Niarks)
'
.
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1 of3

4. 3a.
4a.
b.
6a.
b.
Design a valve spring of a petrol engine for the following operating conditions.
Spring load when the valve is open - 400N
Spring load when the valve is closed - 250N
Maximum inside dia of spring-25mm
Length of spring when the valve is open - 40mm .*-M
Length of spring when the valve is closed - 50mm ,". '0"*"
Maximum permissible shear stress - 400MPa (10 Marks)
i) Define nipping in the leave springs. "-,.'@ Marks)
ii) A locomotive spring has an overall length of 1100mm and sustain a loaff.iffi?5kN at its
centre. The spring has 3 full length leaves and 15 graduated leaves with"a CIe?rtral band of
100mm. All the leaves are stressed at 0.4 GPa when fully loaded. k%,,risib of total spring
depth to width is 2. Determine '"-".
i) Width and thickness of leaves ii) nipping
iii) What load is exerted on the band after the spring is assembbjl9'," (08 Marks)
Derive the Lewis equation for the beam strength of a spur gear tooth. Also list the
assumptions. (03 Marks)
A 55kW motor running at 450rpm is geared to a pump by means of a double helical gearing.
The forged steel pinion on motor shaft has a PQD- of around 200mm and it drives a good
grade C.I gear over the pump shaft at l20rpmJT,-hd allowable stress for both pinion and gear
l"
material should be taken as 224 Nlm1m1 ara 5O N/**' respectively. Assuming A! form
10ME62
(17 Marks)
(14 Marks)
denq.,,& b.
%
teeth with P
: 20" and.Zt: 24. Dedffi ttie gears.
PART _ B
a. Explain with a sketch, the formative number of teeth of bevel gear. (06 Marks)
b. A two teeth right hand worm transmits 2kW at 1500rpm to a36 teeth wheel. The module of
the wheel is 5mm and the pitch diameter of the worm is 60mm. The normal pressure angle is
14.5". The coefficie,nt of friction is found to be 0.06.
i) Find the centre distance, the lead and lead angle.
ii) Deterrnine the forces.
iii) Determine the efficiency of the drive.
A multiple clutch with steel andbrorue is to transmit 8kW at l440rpm. The inner diameter
of the contact is 80mm and the outer diameter of contact is 140mm. The clutch plate
operates in oil with expected coefficient of friction of 0.1 and allowable pressure of
0.35MPa. Assume uniform wear theory. Determine the nurnber of steel and bronze plates,
axial force required, average pressure, actual maximum pressure. (10 Marks)
A 400mm radius brake drum contacts a single shoe as shown in Fig.Q6(b) and sustains
200N - m toque at 500rpm. For a coefficient of friction 0.25, determine
i) Normal force on the shoe.
ii) Required force F to apply the brake for clockwise rotation.
iii) Required force F to apply the brake for counterclockwise rotation.
iv) The dimension 'C' required to make the brake self locking, assuming the other
dimensions remains the sam'e.
v) Heat generated. (10 Marks)
2 of3

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Fie. Q6 (b)
(08 Marks)
b. A 75mm long full journal bearing of diameter 75mm supports aradial load of 12kN at the
shaft speed of 1800 rev/min. Assume ratio of diameter to the diametral clearance as 1000.
The viscosity of oil is 0.01 Pas at operating temperature. Determine the following:
i) Sommerfield number j& d'
ii) The coefficient of friction bq,qp.O.,.g4 Mckee's equation
iii) Amount of heat generated,'* a
iv) Power loss due to frictignY",
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8 a. The following data is gfr€n'for the piston of a four stroke diesel engine:
Cylinder bore - 250mm
Maximum pressure - 4MPa
Bearing pressure at small end of connecting rod: 15MPa
7 a. Explain the following : & d
i) Hydrodynamic theory of lubrication.
ii) Bearing characteristics number and bearing modulus.
iii) Sommerfield number. i l''.il;
Length ofp-iry$.tr pin in bush of small end: 0.45D
Ratio of iff#flto outer dia of piston pin: 0.6
a"i*,cd:*p ffiffiffi::'.Hfl::,'ffi*l;i;,:1T-i?#e
.ic1+i. * ;. -$Pulate
.;" i) Outer dia of the piston pin
(12 Marks)
d* "-.1
$ ii) Inner dia ofpiston pin
,,.,..,'i.'....'', iii) Mean dia of piston boss
, .ih" iv) Check for bending stress (10 Marks)
.Ar'; b. Determine the dimensions of cross section of the connecting rod for a diesel engine with the
T'*,}" following data :
qi*1,,!.$r.. ", .cylinder bore = 100mm
Length of connecting rod: 350mm
Maximum gas pressure : 4MPa
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(10 Marks)

6. USN 10ME64
(10 Marks)
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Finite Element Method
Time: 3 hrs. Max. Marks:100
Note: Answer FIVE full questions, selecting
at least TWO questionsfrom each parL
PART _ A
I a. What is Finite Element Method (FEMX Explain the steps involved in FElvI. (10 Marks)
b. Differentiate between plane stress and plane strain problems. Also sfate the stress strain
relations for both. (10 Marks)
2 a. State the principle of minimum potential energy and apply the same to determine nodal
displacement of a spring system shown in Fig Q.2(a) . (10 Marks)
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kr=h Nlrnn,
kr'h= 6o ir/",,
kh = frvr,nr,
fr"fooc
Fr,l5oM, F3-fu0ru
b. Using Rayleigh's - Ritz method, derive an expression for roaximum deflection of the simply
supported beam with point load 'p' at centre. (10 Marks)
3 a. Derive the shapo function for triangular element (CST Elernent) in natural co-ordinate
system. (10 Marks)
b. Derive an expression for Jacobean matrix for a four noded quadrilateral element. (10 Marks)
4 a. A steprped bar is shown in Fig. 4(a).
Deterniine i) The nodal displacement and nodal forces
.ii)
The stresses in each element
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Fig.Q2 (a)
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1 of2

7. 10ME64
b. Solve the lbllowing system of equations by Gauss Elimination method.
xt+xr*)tr=6
xr-xz*Zxr=J
xt+2xz-xt='2 (10 Marks)
PART _ B
Derive the shape function for a quadratic bar element using Lagrange's interpolation.
(10 Marks)
5a.
b.
la.
b.
Evaluate i [rr^ + x' +--llo.j, L (x+2).1
Using one - point and two - point Gauss quadrature.
a. Derive the stifftress matrix for truss element.
b. For the two bar truss shown in Fig.6 (b), determine
Assume E :200GP?, A:6 x l-ari
Fie.Q6 (b) )n
(10 Marks)
(10 Marks)
nodal displacements.
(10 Marks)
ffi ?,.-
:
Fig.Q7 (b)
Derive element conductivity matrix for one dirnensional heat flow element. (10 Marks)
Find the teneperature distribution and heat transfer through an iron fin of thickness 5mm,
height 50mm and width 1000mm. The heat transfer coefficient around the fin is 10Wim2 K
and ambient temperature is 28'C. The base of fin is at 108oC. Take K : 50W/rr,l K.
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Derive the Hermite shape {iinctions for a beam element.
For the beam fixed at both ends and loaded as shown in
displacement and shapes at node 2, and reaction forces at node 1
ll1 v-,
(10 Marks)
Fig.Q7(b). Determine the
only. (10 Marks)
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Use two eXernents. (10 Marks)

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b.
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(08 Marks)
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{10 Marksi
(1S Vlarks)
(SE Marks)
{06 t{arks'}
(06 fiarks)
(04 Ntarks)
(tr0 Marks)
Sixth Semester B.E" Degree Exarnination, Dec"2015/Jan"20tr 5
Mechatronics and Microprocessor
Time: 3 hrs. IvIax. Marks:100
Note: Answer FIVE full questions, selecting
ut least TWO questions from each part-
PART A
E a. Define mechatronics. What are the advantages and disadvantages of mechatronics?{8S Me nks)
b. Exptain wittrr a block diagram the working of a digital camera. (10 Manks)
c. Discuss basic eiernents of a ciosed-loop systern. (05 Manks)
a.
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Expiain static and dynamic characteristics of sensors.
Explain workirlg principle of Hall effect sensor.
Deftne following terms:
i) Hysteresis error
ii) Repeatability
iii) Non-linearity error
Discuss any four solid state switches.
What is stepper motor? Explain various types of stepper motor.
Exptrain inverting and non-inverting op-aflips with a neat sketch.
rffith a neat sketeh, discuss basic elements used in analog tcl rligital converter.
PART _ B
a. State and prove De-Morgan's theorem. Also draw the logic circuit for the sa$1e.
b. Explain any six laws of Boolean algebra.
c. With the hetrp of s5,rnbols and truth table, exptain XOR and NAND gate.
a. What are the differences between microprocessors and microcontrolier:s?
b. Explain with a neat sketch of architecture 8085 microprocessor.
o. Explain the following terminology reiated to microprocessor:
i) Intemrpts
ii) RAN{
iii) Assembler (06 Starks)
Discuss c.lassification of instruction sets of 8085 microprocessor. (10 Marks)
What are buses? Explain types of buses. (&E Marks)
I-ist any four applications of microprocessor. (02 l!arks)
Explain with a neat diagram of the flow of data word and instrumeirtation word. (18 &tarks)
Draw and explain timing diagram for memory write operati,on. (10 Vlarksi
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