Enroll. No. _____________

SILVER OAK COLLEGE OF ENGINEERING & TECHNOLOGY

BE - SEMESTER–V • MID SEMESTER-I EXAMINATION – WINTER 2018

SUBJECT: Design of Machine Elements (2151907) (ME)

DATE: 07-08-2018 TIME:02:00 pm to 03:30 pm TOTAL MARKS:40

Instructions: 1. All the questions are compulsory. 2. Figures to the right indicate full marks. 3. Assume suitable data if required.

Q.1 (a) What is 25Cr4Mo2, X15Cr25Ni12, 55C4 designation of steel? [03]

(b) State different equations used for thick cylinder design with their conditions and

limitations

[03]

(c) What are preferred numbers? The maximum & minimum load carrying capacities

of dumpers in a manufacturing unit are 40 kN and 630 kN respectively. The

company is interested in developing seven models in this range. Specify their load

carrying capacities.

[04]

Q.2 (a) Two pulleys, one 450 mm diameter and other 200 mm diameter on parallel shaft

1.95 m apart are connected by a cross-belt. Find the length of the belt required and

the angle of contact between the belt and each pulley.

What power can be transmitted by the belt when the larger pulley rotates at 200

rpm. If the maximum permissible tension in the belt is 1 kN and the coefficient of

friction between the belt and the pulley is 0.25?

[06]

(b) A component machined from a plate made of steel 45C8 (Sut = 630 MPa) is shown

in figure: 1. It is subjected to a completely reversed axial force of 50 kN. The

expected reliability is 90% and the factor of safety is 2. The size factor (Kb) is 0.85,

Surface finish factor (Ka) = 0.76. Determine the plate thickness t for infinite life, if

the notch sensitivity factor (q) is 0.8.(Take Reliability factor (Kc) =0.897,

Kt =2.27)

Figure: 1

[05]

(c) What are the principles of design for manufacture and assemblies (DFMA)? [04]

OR

Q.2 (a) Derive the ratio of driving tensions for a flat belt drive [06]

(b) A shaft section where the diameter changes from 430 mm to 300 mm, a fillet radius

of 7.5 mm is provided. This section is subjected to a constant bending moment of

470 kN-m. following data may be assumed :

Yield strength of shaft material (Syt) = 350 MPa;

[05]

Endurance limit of specimen = 210 MPa; q = 0.8, Sut = 500 MPa; Kb = 0.75,

Ka = 0.8, fatigue stress concentration factor (Kf) = 2.28

Table for the theoretical stress concentration factor (Kt) is

(r/d) 0.025 0.05 0.1

Kt 2.6 2.05 1.66

Where ‘r’ is fillet radius and ‘d’ shaft diameter. Determine the expected life of the

shaft.

(c) Write a note on belt materials. [04]

Q.3 (a) A bar of steel having corrected endurance strength of 275 MPa, tensile yield

strength of 415 MPa and ultimate tensile strength of 550 MPa. If it is subjected to

an alternating torsional stress of ± 250 MPa, find the factor of safety against

fatigue failure and the expected life of the component.

[06]

(b) A thick cylinder having 120 mm external diameter and 60 mm internal diameter is

subjected to an internal fluid pressure of 15 MPa. Determine the hoop and radial

stresses at inner and outer surface of cylinder and at radius= 45 mm. Also sketch

curves showing the stresses distribution.

[05]

(c) Define stress concentration and state the methods of reducing stress concentration. [04]

OR

Q.3 (a) A rotating shaft, subjected to a non-rotating force of 5 kN and simply supported

between two bearings A and E is shown in Figure: 2. The

shaft is machined from plain carbon steel 30C8 (Sut = 500 MPa) and the expected

reliability is 90%. The corrected endurance limit of the bar is 96.37 MPa. The

equivalent notch radius at the fillet section can be taken as 3 mm. What is the life

of the shaft? Take Ka = 0.79, Kb = 0.85, Kc = 0.897, Modified stress concentration

factor (Kd) = 0.64.

Figure: 2

[06]

(b) An air receiver consisting of a cylinder closed by

hemispherical ends shown in figure: 3. It has a storage

capacity of 0.25 m3 and an operating internal pressure of

5 MPa. It is made of plain carbon steel 10C4

(Sut= 340 N/mm2) and the factor of safety is 4. Figure: 3

Neglecting the effect of welded joints, determine the dimension of the receiver.

[05]

(c) Define Notch sensitivity and draw S-N Diagram for low & high cycle fatigue. [04]

Enroll. No. _____________

SILVER OAK COLLEGE OF ENGINEERING & TECHNOLOGY

ADITYA SILVER OAK INSTITUTE OF TECHNOLOGY

BE - SEMESTER–V • MID SEMESTER-I EXAMINATION – WINTER 2018

SUBJECT: FLUID POWER ENGINEERING (2151903) (ME)

DATE: 10-08-2018 TIME: 02:00 pm to 03:30 pm TOTAL MARKS:40

Instructions: 1. All the questions are compulsory. 2. Figures to the right indicate full marks. 3. Assume suitable data if required.

Q.1 (a) Explain root blower with neat sketch. [03]

(b) Write advantages and disadvantages of hydroelectric power plant. [03]

(c) Give function of the following elements of hydropower plant:

1) Spillway 2) Trash rack 3) Penstock 4) Surge tank

[04]

Q.2 (a) A jet of water having velocity of 40 m/s impinges without shock on a series of vanes

moving at 12 m/s. The jet is making an angle of 20º with the direction of the motion

of vane. Relative velocity at outlet is 0.9 times the relative velocity at inlet and

absolute velocity of water at exit is normal to the direction of motion of vane. Now,

calculate:

a) Vane angles at inlet and outlet.

b) Work done on vane per kg of water.

c) Efficiency

[06]

(b) With usual notations derive an expression for indicated work of reciprocating air

compressor by considering clearance.

[05]

(c) Justify the need for multi-staging in a reciprocating air compressor. [04]

OR

Q.2 (a) A small ship driven by reaction jets and discharging at stern is estimated to have a

relative velocity of 12 m/s when moving at 30 km/hr. The cross-sectional area of

the jets at the discharge is 240 cm2. Find the resistance to the motion of the ship

and propulsive work if water enters through orifice facing the direction of motion

of ship and pump is 85 % and friction losses in the pipe are equivalent to 3.6 m of

water head. Calculate: a) Power required to drive the pump

b) Overall efficiency of pump.

[06]

(b) Derive the equation of forces when jet strikes tangentially at one end of

symmetrical fixed curved blade.

[05]

(c) Compare reciprocating compressor & centrifugal compressor. [04]

Q.3 (a) Atmospheric air at 1 bar and 20˚C is taken into a simple compressor having zero

clearance. It is compressed according to law (PV1.2 = C) to the discharge pressure of

4 bar. The discharge is taken through a regulating valve into a closed vessel of 3 m3

capacity. Here the initial conditions were 1 bar and 20˚C and after charging for 4.2

minutes were 3.5 bar and 25˚C. Calculate by neglecting the clearance of compressor.

(i) The volume of air taken per minute at atmospheric conditions.

(ii) The indicated power required to drive the machine.

[06]

(b) Show that the efficiency of propulsion when the inlet orifice are at the right angles

to the direction of motion of ship does not exceed by 50%.

[05]

(c) Explain construction & working of scroll compressor. [04]

OR

Q.3 (a) Show that when a jet of water impinges on a series of curved vanes maximum

efficiency is obtained when the vane is semi circular and the velocity of jet is double

the velocity of vane.

[06]

(b) Show that the efficiency of propulsion when the inlet orifice facing the direction of

motion of ship is given by η = 2u/ V+2u, where V is absolute velocity of issuing jet

and u is velocity of ship.

[05]

(c) Explain construction & working of screw compressor. [04]

Enroll. No. _____________

SILVER OAK COLLEGE OF ENGINEERING & TECHNOLOGY

ADITYA SILVER OAK INSTITUTE OF TECHNOLOGY

BE - SEMESTER–V• MID SEMESTER-I EXAMINATION – WINTER 2018

SUBJECT: HEAT TRANSFER (2151909) (ME)

DATE: 11-08-2018 TIME: 02:00 pm to 03:30 pm TOTAL MARKS:40

Instructions: 1. All the questions are compulsory. 2. Figures to the right indicate full marks. 3. Assume suitable data if required.

Q.1 (a) Define : Total Emissive power, Irradiation and Emissivity [03]

(b) What is thermal conductivity? Explain its importance in heat conduction

problems.

[03]

(c) State and prove Kirchoff’s law of radiation. [04]

Q.2 (a) Define total emissive power (Eb) and intensity of radiation (Ib). Show that

Eb = π×Ib.

[06]

(b) Consider two large parallel plates, one at temperature at 727 C with

emissivity 0.8 and other at 227 C with emissivity 0.4. An aluminum

radiation shield with an emissivity of 0.05 on both sides is placed between

two plates. Calculate reduction in heat transfer rate between two plates as

a result of shield.

[05]

(c) Write any four important characteristics of shape factor. [04]

OR

Q.2 (a) Derive an expression for the shape factor in case of radiation exchange

between two black bodies.

[06]

(b) An enclosure measures 1.5m* 1.5m with a height of 2m under steady state

conditions, The wall and ceiling are maintained at 525 K and floor is at

400K. Determine net radiation to floor. Take emissivity of ceiling and wall

=0.85 and emissivity of floor = 0.75.

[05]

(c) State Stefan- Boltzmann law and define Absorptivity, solid angle, and steady

state.

[04]

Q.3 (a) Derive general heat conduction equation in Cartesian coordinates. [06]

(b) The wall of a boiler is made up of 250 mm of fire brick (k = 1.05 W/mK),

120 mm of insulation brick (k = 0.15 W/mK), and 200 mm of red brick (k =

0.85 W/mK). The inner and outer surface temperatures of the wall are 850

C and 65 C respectively.

Calculate 1. The rate of Heat flow per square meter

2. The temperatures at contact surfaces.

[05]

(c) State and explain Fourier’s law for heat transfer. Mention the assumptions

on which it is based.

[04]

OR

Q.3 (a) The walls of a refrigerated truck consist of 1.2 mm thick steel sheet (k=18

W/m-K) at the outer surface, 22 mm thick cork (k=0.04 W/m-K) on the inner

surface. Consider Heat transfer coefficient of 5 W/m2-K (between inside air

and inside surface) and Heat transfer coefficient of 30 W/m2-K (between

outside air and outside surface). The temperatures at the inside and outside air

are 0°C& 35°C respectively.

Calculate (1) heat transfer rate (2) steel-cork interface temp.

[06]

(b) What is the critical thickness of insulation on a small diameter wire and a

steam pipe? Explain its physical significance in both the cases & derive an

expression for critical radius of cylinder.

[05]

(c) Explain how conduction phenomena occurs inside solid objects, arrange

the following in decreasing order of thermal conductivity k values.

1. Diamond

2. Iron

3. Aluminium

4. Silver

[04]

Enroll. No. _____________________

SILVER OAK COLLEGE OF ENGINEERING & TECHNOLOGY

BE - SEMESTER– V • MID SEMESTER- I EXAMINATION – WINTER 2018

SUBJECT: Control Engineering (2151908) (ME)

DATE: 08/08/2018 TIME: 02:00 am to 03:30 pm TOTAL MARKS:40

Instructions: 1. All the questions are compulsory. 2. Figures to the right indicate full marks. 3. Assume suitable data if required.

Q.1 (a) Explain any one Mechanical Close Loop Control System. [03]

(b) Compare hydraulic control system with pneumatic control system in detail. [03]

(c) Write comparison between Open loop system and Closed loop system. [04]

Q.2 (a) Explain Basic Hydraulic Circuit with its Components. [06]

(b) Using the block diagram reduction techniques, find the closed loop transfer

function of the system whose block diagram is given in Fig.

[05]

(c) Find the transfer function for the fig. using signal flow graphs.

[04]

OR

Q.2 (a) Explain Basic pneumatic Circuit with its Components. [06]

(b) Using the block diagram reduction techniques, find the closed loop transfer

function of the system whose block diagram is given in Fig.

[05]

(c) For the signal flow graph of a multiple loop system shown in figure, determine

C(s)/R(s) using Mason’s gain formula

[04]

Q.3 (a) Using Routh criterion, discuss about the stability for the system having

characteristics equation is given as

3S7 + 9S6 + 6S5 + 4S4 + 7S3 + 8S2 + 2S + 6 = 0

[06]

(b) Using R-H criterion determine the stability of the system whose characteristic

equation is given by

S5 + 1.5S4 + 2S3 + 4S2 + 5S + 10 = 0

[05]

(c) What is control System? Explain Advantages and disadvantages of control

system.

[04]

OR

Q.3 (a) Using Routh criterion, discuss about the stability for the system having

characteristics equation is given as

S6 + 2S5 + 8S4 + 12S3 + 20S2 + 16S + 16 = 0

[06]

(b) Write short note on Dashpots. [05]

(c) List out any five open loop & close loop mechanical systems [04]

Enroll. No. _____________

SILVER OAK COLLEGE OF ENGINEERING & TECHNOLOGY

BE - SEMESTER–V • MID SEMESTER-I EXAMINATION – WINTER 2018

SUBJECT: THEORY OF MACHINE (2151902) (MECHANICAL)

DATE: 09-08-2018 TIME: 02:00 PM to 03:30 PM TOTAL MARKS:40

Instructions: 1. All the questions are compulsory. 2. Figures to the right indicate full marks. 3. Assume suitable data if required.

Q.1* (a) Define the following.

a. Sensitiveness

b. Hunting

c. Isochronous

[03]

(b) What are the effects of friction and of adding a central weight to the sleeve of a

Watt governor?

[03]

(c) What do you understand by gyroscopic couple? Derive a formula for its magnitude. [04]

Q.2 (a) Describe with a neat sketch a centrifugal clutch and deduce an equation for the

total torque transmitted.

[06]

(b) The turbine rotor of a ship has a mass of 3500 kg. It has a radius of gyration of 0.45

m and a speed of 3000 rpm. clockwise when looking from stern. Determine the

gyroscopic couple and its effect upon the ship:

a) when the ship is steering to the left on a curve of 100 m radius at a speed of 36

km/h.

b) when the ship is pitching in a simple harmonic motion, the bow falling with its

maximum velocity. The period of pitching is 40 seconds and the total angular

displacement between the two extreme positions of pitching is 12 degrees.

[05]

(c) What is the function of a governor? How does it differ from that of a flywheel? [04]

OR

Q.2 (a) A centrifugal clutch is to transmit 15 kW at 900 rpm. The shoes are four in number.

The speed at which the engagement begins is 4/5th of the running speed. The inside

radius of the pulley rim is 150 mm and the centre of gravity of the shoe lies at 120

mm from the centre of the spider. The shoes are lined with Ferrodo for which the

coefficient of friction may be taken as 0.25. Determine: 1. Mass of the shoes, and 2.

Size of the shoes, if angle subtended by the shoes at the centre of the spider is 60º

and the pressure exerted on the shoes is 0.1 N/mm2.

[06]

(b) Explain the effect of the gyroscopic couple on the reaction of the four wheels of a

vehicle negotiating a curve.

[05]

(c) Explain the following cases in naval ships

a) Pitching b) Rolling

[04]

Q.3 (a) A multi-disc clutch has three discs on the driving shaft and two on the driven shaft.

The outside diameter of the contact surfaces is 240 mm and inside diameter 120

mm. Assuming uniform wear and coefficient of friction as 0.3, find the maximum

axial intensity of pressure between the discs for transmitting 25 kW at 1575 rpm.

[06]

(b) Explain gyroscopic couple and discuss its effect on an aero plane taking turns when

viewed from rear.

[05]

(c) State the different types of governors. What is the difference between centrifugal

and inertia type governors? Why is the former preferred to the latter?

[04]

OR

Q.3 (a) Explain the term height of the governor. Derive an expression for the height in the

case of a Watt governor. What are the limitations of a Watt governor?

[06]

(b) Derive the equation for the torque transmitted by the cone clutch with usual

notation considering uniform wear.

[05]

(c) The turbine rotor of a ship has a mass of 8 tonnes and a radius of gyration 0.6 m.

It rotates at 1800 rpm clockwise, when looking from the stern. Determine the

gyroscopic couple, if the ship travels at 100 km/hr and steer to the left in a curve of

75 m radius.

[04]