MORE IN Elements of Mechanical Engg.
GTU First Year Engineering (Semester 1)
Elements of Mechanical Engg.
June 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) Explain working of four stroke Diesel Engine with P-V diagram.
5 M
1 (b) A four cylinder four stroke petrol engine has 100mm bore and stroke is 1.3 times bore. It consumes 4 kg of fuel per hour having calorific value of 40500 kJ/kg. If engine speed is 850 rpm. Find its Indicated thermal efficiency. The mean effective pressure is 0.75 N/mm2
5 M
1 (c) Define Pressure and explain Absolute Pressure, Guage Pressure and Atmospheric pressure
4 M

2 (a) Explain construction and working of Locomotive boiler with neat sketch.
7 M
2 (b) State the function of the following (1) Fusible plug. (2) Economiser (3) Safety valve
3 M
2 (c) Define : (i) Sensible heat (ii) Latent heat (iii)Dryness fraction (iv)Enthalpy of evaporation.
4 M

3 (a) Derive Expression PV/T=constant with the help of Boyle?s law and Charle?s law
5 M
3 (b) A steel cylinder contains O2 at pressure of 25 bar and temperature of 27°C, After using some quantity of the gas 0the pressure was found to be 5 bar and temperature of 20°C. 700 liters of O2 was originally put in the cylinder at NTP Density of O2 at NTP is 1.43 gm/liter. Find the mass of O2 used.
6 M
3 (c) Define Calorific value and explain Higher and Lower Calorific values.
3 M

4 (a) Explain Separating Calorimeter with neat sketch.
5 M
4 (b) Find internal energy of 1 kg of steam at a pressure of 15 bar when
(i) The steam is superheated with temperature of 400°C.
(ii) The steam is wet with dryness fraction =0.9Take Cps=2.1 kJ/kg K
5 M
4 (c) What are different methods of IC engine governing? Explain governing method used in the Petrol engine.
4 M

5 (a) Derive expression for the efficiency of the Carnot cycle
5 M
5 (b) In an ideal Diesel cycle the temperature at the beginning and at the end of compression are 57°C and 603°C. The temperature at the beginning and at the end of expansion are 1950°C and 870°C.Find the ideal efficiency of the cycle. If the pressure is 1 bar find the maximum pressure in the cycle.
5 M
5 (c) Explain Oldham?s coupling with neat sketch.
4 M

6 (a) Explain working of main parts of centrifugal pump with neat sketc
5 M
6 (b) Explain difference between Recipr ocating and Rotodynamic compressor.
5 M
6 (c) Draw and explain Internal expanding brake.
4 M

7 (a) Explain Vapour absorption Refrigeration system with the neat sketch.
6 M
7 (b) Define (i) Hardness (ii) Creep (iii) Resilience (iv) Toughness
4 M
7 (c) What are Bearings and how they are classified?
4 M

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