GUJARAT TECHNOLOGICAL UNIVERSITY
BE SEM- I / II Winter Examination-Dec.-2011
Subject code: 110006
Subject Name: Elements of Mechanical Engineering
- Attempt any five questions.
- Make suitable assumptions wherever necessary.
- Figures to the right indicate full marks.
- Use of Steam Tables and Mollier’s Chart is permissible
Q-1 (a) What is flow and non-flow process?
(b) Define : (i) Sensible heat (ii) Enthalpy of evaporation
(iii) Heat of superheat (iv) Dryness Faction.
(c) Calculate the enthalpy per kg of steam at 10 bar pressure and a temperature of 300 °C. 7 Find also the change in enthalpy if this steam is expanded to 1.4 bar and dryness fraction
of 0.8. Take specific heat of superheat steam equal to 2.29 kj/kgK.
Q-2 (a) What is adiabatic process? Prove with usual notations the law of governing adiabatic
process process as PVY = Constant.
(b) 0.67 kg of gas at 14 bar and 290 °C is expanded to four times the original volum according 7 to the law PV13 = Constant.
Caluculate : (1) The original and final volume of the gas.
(2) The final temperature of the gas .
(3) The final pressure of the gas. Take R = 287 J/kgK.
Q-3 (a) Differentiate between petrol engine and diesel engine.
(b) Derive equeation for air standared efficiency of otto cycle.
(c) In an ideal constant volume cycle the pressure and temperature at the beginning of the comperession are 97 kPa and 50 °C respectively. The volume ratio is 5. The heat supplied 7 during the cycle is 930 kj/kg of working fluid.
Calculate : (1) The maximum temperature attained in the cycle.
(2) The thermal efficiency of the cycle.
(3) Work done during the cycle/kg of working fluide.
Q-4 (a) State the function of the following :
(1) Pressure gauge
(2) Fusible plug
(b) With neat sketch describe the working of two stroke cycle petrol engine.
(c) With neat sketch describe the construction and working of Cochran boiler.
Q-5 (a) Give classification of governor. Explain working of any one with neat sketch.
(b) Classify the centrifugal pump and explain with neat sketch the vertex type centrifugal Pump.
(c) Classify the air compressor . Differentiate between reciprocating compressor and rotary compressor.
Q-6 (a) What is refrigerant? State the most widely used refrigerant.
(b) With neat sketch explain vapour compression refrigeration cycle.
(c) Explain with neat sketch split air conditioner. State its advantages.
Q-7 (a) What is zeroth law of thermodynamics.
(b) With simple sketch explain working of disc clutch.
(c) Write short note on: Type of belt drive.
Define : Malleability , Compressive strength , Toughness and Brittleness.
(b)Write similarities between heat transfer and work transfer.
(c)Write advantages of gaseous fuels over other fuels. Write short note on LPG.
(a) Explain different types of watershed development techniques
(b) Explain different modes of transportation and their Importance
( c) Explain traffic planning and its importance
Q.5 (a) Explain different types of Building loads
(b) The offset from boundary of an agricultural plot are taken as below at the 05 interval of 20 m . Calculate the area between the base line and boundary by Simpsons rule and trapezoidal rule The offsets are 0.24, 0.89, 1.45, 2.56,
5.67, 8.76, 7.88, 4.56,3.66,2.5 and 1.35.
( c) Explain properties and uses of concrete
Q.5 (a) Explain the different types of water conveyance structures
(b) Enlist different types of doors and draw sketch of panelled door.
Describe (i) isogonic line (ii) Application of contour map