Intercooler pressure for perfect inter-cooling

Question

Question 1: Differentiate between impulse and reaction turbines.

Question 2: A single phase single acting reciprocating air compressor has a bore of 20 cm and a stroke of 30 cm. The compressor runs at 600 rpm. The clearance volume is 4% of the swept volume and index of compression and expansion is 1.3. The suction conditions are 0.97 bar and 27^o C and delivery pressure is 5.6 bar. The atmospheric conditions are at 1.01 bar and 17^o C. Find out:

a) The free air delivered in m³/min 
b) The volumetric efficiency referred to the free air conditions. 
c) The indicated power.

Question 3: 2 kg/s of air enters the LP cylinder of a two phase reciprocating air compressor. The total pressure ratio is 9. The air at inlet to compressor is at 100 kPa and 35^o C. The index of compression in each cylinder is 1.3. Find out the intercooler pressure for perfect inter-cooling. Also, find out the minimum power needed for compression, and percentage saving over single phase compression. Tame R = 0.287 kJ/kg K and Cp = 1 kJ/kg K.

Question 4: A three phase reciprocating air compressor compresses air from 1 bar and 17^oC to 35 bar. The law of compression is pv1.25 = c. The law is same for all phases of compression. Find out the minimum power required to compress 15 m³/min of free air. Also find out the intermediate pressures. Suppose that the perfect inter cooling and neglect the clearance.

Question 5: A four cylinder, double acting compressor is needed to compress 30 m³/min of air at 1 bar and 25^o C at a pressure of 15 bar. Find out the capacity of motor needed and cylinder dimensions if the following data are given.

a) Speed of the compressor = 310 rpm
b) Clearance volume = 3.5%
c) Stroke to bore ratio = 1.2
d) Mechanical efficiency = 82%
e) Index of compression 1.3

Question 6: One kg or air at 35^o C DBT and 60% RH is mixed with 2 kg of air at 20^o C DBT and 13^o C dew point temperature. Compute the vapors pressure and dew point temperature of stream one, enthalpy of both streams and specific humidity of the mixture.

Question 7: With a schematic diagram, describe the requirement of a winter air conditioning system.

Question 8: Define the term Specific Humidity, Dry Bulb Temperature, Relative Humidity and Wet Bulb Temperature.

Question 9: 100 m³ of air per minute at 15^o C DBT and 80% RH are heated till its temperature is 20^o C. Compute heat added to air per minute, RH of the heated air and wet bulb temperature of the heated air.

Question10: Write down the merits and demerits of vapor absorption system over a vapor compression system.