VTU Elements of Mechanical Engg. - January 2013 Exam Question Paper

VTU First Year Engineering (P Cycle) (Semester 2)
Elements of Mechanical Engg.
January 2013

Total marks: --
Total time: --

INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

1 (a) (i) Hydro energy is considered as ____________.
(a) Tidal Energy (b) Heat energy (c) Indirect Solar energy (d) Solar Energy

1 M

1 (a) (ii) The primary source of solar energy are:
(a) Heliochemical process (b) Helioelectrical process (c) Heliothermal process (d) All of these

1 M

1 (a) (iii) Lancashire boiler is a ___________ boiler.
(a) Water tube (b) Fire tube (c) Gas tube (d) Air tube

1 M

1 (a) (iv) The temperature at which water starts to boil in static pressure is ____________.
(a) Sensible heat (b) Saturation temperature (c) Wet steam temperature (d) Dry steam temperature

1 M

1 (b) Find the total enthalpy of 0.6 kg of steam with an initial dryness fraction of 0.7 is heated at a constant pressure of 7 bar till its temperature rises to 250°C. Assume CPS = 2.25 KJ/KgK. From steam table, at 7 bar, hf=679.1 KJ/Kg. hfg=2064.9 KJ/kg, Tsat=165°C.

6 M

1(c) Explain with a neat sketch, the working principle of Lancashire boiler.

10 M

2 (a) (i) It is an example of reaction turbine.
(a) De-Leval turbine (b) Kaplan turbine (c) Flow turbine (d) Pelton wheel

1 M

2 (a) (ii) Open cycle turbines uses _______________ as the working substance.
(a) Ammonia (b) Nitrogen (c) Air (d) CO₂

1 M

2 (a) (iii) ____________ is an example for reaction water turbine.
(a) Pelton wheel (b) Francis turbine (c) Kaplan turbine (d) Both B and C

1 M

2 (a) (iv) Method of improving efficiency by successive stages in a turbine is ___________.
(a) governing (b) Compounding (c) Supercharging (d) Turbocharging

1 M

2 (b) With a neat sketch explain the working of open cycle gas turbine.

8 M

2 (c) Sketch and explain the working of reaction steam turbine with the help of pressure and velocity profile diagram.

8 M

3 (a) (i) The motion of a piston is ______________.
(a) Rotory (b) Oscillatory (c) Rectilinear (d) Circular

1 M

3 (a) (iii) The power measured in the crankshaft of engine is ____________.
(a) Indicated power (b) Brake power (c) Horse power (d) Torque

1 M

3 (a)(ii) Diesel engine is also called as
(a) 4-stroke engine (b) 2-stroke engine (c) C.I. engine (d) S.I. engine

1 M

3 (c) A 4-cylinder two stroke petrol engine develops 30 kW at 2500 rpm. The mean effective pressure on each piston is 8 bar and the mechanical efficiency is 80%. Calculate the diameter and stroke of each cylinder, stroke to bore ratio 1.5. Also calculate the specific fuel consumption if brake thermal efficiency is 28%. The calorific value of fuel is 43900 KJ/kg.

8 M

3(a)(iv) __________ is fed into the diesel engine through the inlet valve.
(a) Fuel (b) Diesel (c) Air fuel mixture (d) Air

1 M

3(b) With the help of a line diagram,explain the working of a two-stroke petrol engine.

8 M

4(a) (i) _____________ is the heart of the refrigerator.
(a) Compressor (b) Condenser (c) Expansion valve (d) Evaporator

1 M

4(a)(ii) The ratio of heat absorbed in a system to work supplied is ____________.
(a) Refrigeration effect (b) COP (c) Ton of refrigeration (d) Coding effect

1 M

4(a)(iii) In a refrigerator exchange of heat takes place in ______________.
(a) Condenser (b) Evaporator (c) Compressor (d) Both A and B

1 M

4(a)(iv) _____________ is the refrigerant used in vapour compression refrigerator.
(a) Ammonia (b) Air (c) Freon-12 (d) Nitrogen

1 M

4(b) Explain with a neat sketch the working of vapour compression refrigerator

8 M

4(c) With a neat sketch explain the working of a typical room air conditioner

8 M

5(a)(i) _____________ objects are produced in engine lathe.
(a) Plane objects (b) Curved objects (c) Circular objects (d) None of these

1 M

5(a)(ii) Taper turning is an operation of producing ___________ on a work piece.
(a) Tapping (b) Reaming (c) Taper (d) Boring

1 M

5(a)(iii) Flute in a twist drill is used for,
(a) Flow of coolant (b) Removal of material (c) Easy removal of curl chips (d) All of these

1 M

5(a)(iv) ___________ is not a drilling operation.
(a) Taper turning (b) Reaming (c) Knurling (d) Turning

1 M

5(b) Explain with a schematic diagram, show how a centre lathe is specified

8 M

5(c) How are counter sinking and counter boring operation done on a drilling machine? Explain with suitable sketches

8 M

6(a)(i) Milling cutter is a ____________.
(a) Multipoint cutting tool (b) Abrasive cutter (c) Single point cutting tool (d) Metal removing machine

1 M

6(a)(ii) Milling is a ________________.
(a) Metal removal process (b) Metal cutting process (c) Metal joint process (d) None of these

1 M

6(a)(iii) ______________ is a natural abrasive mineral consists of aluminium oxide.
(a) Diamond (b) Corundum (c) Emery (d) Aluminium nitrate

1 M

6(a)(iv) Grinding is also called as ______________.
(a) Turning (b) Metal cutting (c) Abrasive machining (d) Lapping

1 M

6(b) Sketch and explain, the principle and working of a horizontal milling machine.

8 M

6(c) With a neat sketch, explain the surface grinding machine

8 M

7(a)(i) Welding is a _____________ process used for metals.
(a) Metallurgical joining (b) Forged forming (c) Mechanical joining (d) Adhesive bonding

1 M

7(a)(ii) Gas welding is a __________________ method of joining two metals.
(a) Fission (b) Fusion (c) Gas reaction (d) Oxidizing

1 M

7(a)(iii) Lubricants are used to reduce the _____________ in machines.
(a) Efficiency (b) Effectiveness (c) Friction (d) Torque

1 M

7(a)(iv) In thrust bearing the bearing pressure will be ______________.
(a) Radial (b) Circular (c) Axial (d) Centrifugal

1 M

7(b) With a neat sketch, explain the working of oxy-acetylene gas welding

8 M

7(c) List the important properties of a good lubricant

8 M

8(a)(i) The ______________ motion is the simplest form of transmitting power with minimum loses.
(a) Rotational (b) Rectilinear (c) Oscillatory (d) None of these

1 M

8(a)(ii) _______________ is called as positive drive mechanisms.
(a) Belt drive (b) Chain drive (c) Gear drive (d) Both B & C

1 M

8(a)(iii) ______________ type of gear drive is used for transmitting power between two perpendicular shafts.
(a) Bevel gear (b) Elliptical gear (c) Helical gears (d) Spur gear

1 M

8(a)(iv) For power transmission _____________ is the most suitable power transmission.
(a) Belt drive (b) V-belt drive (c) Rope drive (d) Gear drive

1 M

8(b) Derive an expression for length of a belt in an open drive system

8 M

8(c) Two spur gears A and B connect two parallel shafts that are 500 mm apart. Gear A runs at 400 rpm and gear B at 200 rpm. If the circular pitch is 30 mm, calculate the number of teeth on gears A and B

8 M

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