GTU Elements of Mechanical Engineering Question Paper Dec 2011

GTU Elements of Mechanical Engineering

Question Paper Dec 2011


        BE SEM- I  II Winter Examination-Dec.-2011

     Subject Name: Elements of Mechanical Engineering


  1. Attempt any five questions.
  2. Make suitable assumptions wherever necessary.
  3. Figures to the right indicate full marks.
  4. Use of Steam Tables and Mollier’s Chart is permissible

Q-1 (a) What is flow and non-flow process?                                                                                      3

(b)  Define : (i) Sensible heat                (ii) Enthalpy of evaporation                                            4

                           (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                 7

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.                                                            3

(b)  Derive equeation for air standared efficiency of otto cycle.                                                    4

(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 :                                                                                      3

(1)    Pressure gauge

(2)    Fusible plug

(3)    superheater

(b)  With neat sketch describe the working of two stroke cycle petrol engine.                                 4

(c)  With neat sketch describe the construction and working of Cochran boiler.                               7

Q-5 (a) Give classification of governor. Explain working of any one with neat sketch.                          3

(b) Classify the centrifugal pump and explain with neat sketch the vertex type centrifugal              4 Pump.

(c) Classify the air compressor . Differentiate between reciprocating compressor and                     7 rotary compressor.

Q-6 (a) What is refrigerant? State the most widely used refrigerant.                                                     3

(b)  With neat sketch explain vapour compression refrigeration cycle.                                           4

(c)  Explain with neat sketch split air conditioner. State its advantages.                                         7

Q-7 (a) What is zeroth law of thermodynamics.                                                                                 3

(b)  With simple sketch explain working of disc clutch.                                                                4

(c)    Write short note on: Type of belt drive.                                                                               7

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