3 kg of air at 1.5 bar pressure and 77°C temperature at state 1 is compressed polytropically to state2 at pressure 7.5 bar, index of compression being 1.2. It is then cooled at constant temperature to its original state 1. Find the net work done and heat transferred.
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Explanation:
3 kg of air at 1.5 bar pressure and 77°C temperature at state 1 is compressed polytropically to state2 at pressure 7.5 bar, index of compression being 1.2. It is then cooled at constant temperature to its original state 1. Find the net work done and heat transferred.
answer
Transcribed image text: 4. 3 kg of air at 1.5 bar pressure and 77oC temperature at state 1 is compressed polytropically to state 2 at pressure 7.5 bar, index of compression being 1.2. It is then cooled at constant temperature to its original state 1. Find the net work done and heat transferred. 5. An air compressor requires shaft work of 200 kJ/kg of air and the compression of air causes increase in enthalpy of air by 100 kJ/kg of air. Cooling water required for cooling the compressor picks up heat of 90 kJ/kg of air. Determine the heat transferred from compressor to atmosphere. 6. Steam at a 6.87 bar, 205°C, enters in an insulated nozzle witha velocity of 50 m/s. It leaves at a pressure of 1.37 bar and a velocity of 500 m/s. Determine the final enthalpy of steam.