Applied Thermodynamics SPPU Insem Question Paper Mar 2023

Questions

1. Q1

   1. a)

      A refrigeration machine using R-12 as refrigerant operates between the pressures 2.5 bar and 9 bar. The compression is isentropic and there is no under cooling in the condenser. The vapour is in dry saturated condition at the beginning of the compression. Estimate theoretical C.O.P. if the actual C.O.P. is 0.65 of theoretical value, calculate the net cooling produced per hour. The refrigerant flow is 5 kg/min. Properties of refrigerant are: Pressure Temperature Liquid Vapour Entropy of (bar) (ºC) enthalpy enthalpy saturated vapour (kJ/kg) (kJ/kg) (kJ/kg-K) 9 36 70.55 201.8 0.6836 2.5 -7 29.62 184.5 0.7001

      [7]
   2. b)

      Draw and explain the following processes: i) Sensible heating ii) Humidification iii) Sensible cooling & humidification iv) Sensible cooling & dehumidification 2

      [8]
   OR

2. Q2

   1. a)

      Explain with neat sketch the working of a simple vapor absorption refrigeration cycle.

      [7]
   2. b)

      The pressure and temperature of mixture of dry air and water vapour are 736 mm of Hg and 21 ºC. The dew point temperature of the mixture is 15 ºC. Find the following. i) Partial pressure of water vapour in the mixture ii) Relative Humidity iii) Enthalpy of mixture iv) Specific Volume of mixture per kg of dry air

      [8]

3. Q3

   1. a)

      What is a heat engine? Differentiate between the internal and external combustion engines with applications.

      [7]
   2. b)

      Compare between the air standard with fuel air cycle and actual cycle.

      [8]
   OR

4. Q4

   1. a)

      Draw valve timing diagram for 4-stroke S.I. engine and explain the same.

      [7]
   2. b)

      Differentiate between S.I. and C.I. engine with applications explain in detail. 

      [8]