Gujarat Technological UniversityWinter 2025 examination

GTU 3110006 Basic Mechanical Engineering (BME) Winter 2025 Question Paper & PDF

B.E. · Common Engineering · Semesters 1 and 2 · Subject code 3110006
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Total
70 marks
To pass
23 marks (33%)
Duration
2.5 Hours 2:30 PM – 5:00 PM
Questions
5 with internal choice
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Q.1

14 Marks
(a)
3 marks
Give classification of Cochran boiler and Lancashire boiler.
(b)
4 marks
Write a short note on CNG as a fuel.
(c)
7 marks
iThe absolute pressure in a compressed air tank is 200 kPa. What is the gauge pressure in the tank if atmospheric pressure is 1.01 bar?
iiThe temperature of a system rises by 130°C during a heating process. Express this rise in temperature in kelvins.
iiiA 4-kW resistance heater in a water heater runs for 3 hours to raise the water temperature to the desired level. Determine the amount of electric energy used in both kWh and kJ.

Q.2

14 Marks
(a)
3 marks
State the function of any three mountings in boilers.
(b)
4 marks
Classify engineering materials.
(c)
7 marks

0.4 kg of gas is expanded isentropically from 10 bar and 340°C to 1 bar. It is then heated at constant volume to 3 bar and 340°C and then finally it is compressed isothermally until the initial pressure of 10 bar is attained. Draw the p-V diagram for these processes and find the value of the adiabatic index γ. Take Cp = 1.005 kJ/kgK.

(c)
7 marks

A gas expands from 450 kPa and 130 litres to 150 kPa and 260 litres. The decrease in enthalpy during the process is 55 kJ. Taking Cv = 718 J/kgK, determine (i) change in internal energy, (ii) value of Cp, and (iii) value of R.

Q.3

14 Marks
(a)
3 marks
What is a rigid coupling? What are its types?
(b)
4 marks

Draw a schematic diagram of the vapor compression refrigeration system. Where is the condenser located in a split air-conditioner?

(c)
7 marks

A rigid tank contains 10 kg of water at 90°C. If 8 kg of the water is in the liquid form and the rest is in the vapor form, determine (a) the pressure in the tank and (b) the volume of the tank.

(a)
3 marks
What is a friction clutch? What are its types?
(b)
4 marks

What is the difference between the working principle of vapor compression and vapor absorption refrigeration system?

(c)
7 marks

Find the dryness fraction of steam supplied in a combined separating-and-throttling calorimeter from following data: initial pressure = 10 bar, final pressure = 1 bar, water separated = 1.5 kg, steam discharged from throttling calorimeter = 20 kg, temperature of steam after throttling = 120°C. Take specific heat of superheated steam as 2.1 kJ/kg K.

Q.4

14 Marks
(a)
3 marks
Find the incorrect statements from the following and correct them.
  • Rigid flange coupling is used when axes of shafts are parallel but not in alignment.
  • Pin type flexible coupling is used where angular misalignment is more.
  • Universal coupling requires proper alignment of shaft axes.
  • Oldham’s coupling is for small angular misalignment.
(b)
4 marks
Describe main parts of a centrifugal pump in short.
(c)
7 marks

A Diesel engine has a compression ratio of 15 and heat addition at constant pressure takes place 6% of the stroke. Find the air standard efficiency of the engine.

(a)
3 marks
Draw a labeled diagram of a simple band brake.
(b)
4 marks
Explain any one type of rotary pumps with figure.
(c)
7 marks

In an air standard Otto cycle, the upper and lower limits of absolute temperatures are T3 and T1 respectively. Show that for maximum work, the ratio of compression should have the value r=(T3T1)1.25r = \left(\dfrac{T_3}{T_1}\right)^{1.25}.

Q.5

14 Marks
(a)
3 marks
Which mechanical drive will you suggest in each of the following different situations:
  • When there is less space available.
  • Where ‘slip’ is permitted.
  • When high velocity ratio is required.
(b)
4 marks

What is isothermal efficiency, clearance ratio, and volumetric efficiency of a compressor?

(c)
7 marks

Distinguish between petrol engine and diesel engine. Use the following points: cycle of operation, compression ratio, fuel ignition, governing, engine speed, thermal efficiency, engine weight.

(a)
3 marks
State three disadvantages of using gear drives.
(b)
4 marks
Give classification of air compressors.
(c)
7 marks
The following data refer to a test on I.C. engine:

Indicated power = 42 kW, frictional power = 7 kW, engine speed = 1800 rpm, specific fuel consumption per B.P. = 0.30 kg/kWh, calorific value of fuel used = 43000 kJ/kg. Calculate: (i) mechanical efficiency, (ii) brake thermal efficiency, and

iiiindicated thermal efficiency.

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About this paper

Official Gujarat Technological University (GTU) examination paper for Basic Mechanical Engineering (BME) (Winter 2025, B.E. · Common Engineering, Sem 1). Features complete 70-mark regular & remedial examination pattern, official marking distribution across all 5 questions, and direct 1-click official PDF download.

Transcribed for student exam preparation from Gujarat Technological University official examination archives. Questions, syllabus guidelines, and curriculum marking schemes remain the intellectual property of Gujarat Technological University.

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