Question

Problem 6.030 SI Air is compressed adiabatically in a piston-cylinder assembly from 1 bar, 300 K to 9 bar, 600 K. The air can be modeled as an ideal gas and kinetic and potential energy effects are negligible. Determine the amount of entropy produced, in kJ/K per kg of air, for the compression. What is the minimum theoretical work input, in kj per kg of air, for an adiabatic compression from the given initial state to a final pressure of 9 bar? Note that work is positive into the compressor. Part A Your answer is incorrect. Try again. Determine the amount of entropy produced, in kJ/K per kg of air, for the compression. X kJ/K 66 g/m = the tolerance is +/-5% Click if you would like to Show Work for this question: Open Show Work SHOW HINT Attempts: 2 of 4 used SAVE FOR LATER SUBMIT ANSWER Part B The parts of this question must be completed in order. This part will be available when you complete the part above.

Answer 1

(Part 1) Initial Ti= 3ook Final Compression P = 1 bar T2 =6ook P2 = 9 bar = 0.287 kJ/kg k for air, Cp= 1.005 kJ/kg k adiabatic index, y = Bartlet Raira ideal behaviour Entropy produced in compression (assuoning T2 P2 m(cp lo S2-S Take on=1kg. gas NH Rlo 600 1.005 lo 0.287 los 1 300 AS 0.066009 KJ/K ko/k Part 2 Minimum Theoretical coork is obtained when the process is i sentropic i.e, it doesn't produce entropy. for (Let Tá is final temperature) isen popic process 3 y-1 T2 T 300x ( ) T = - 562.03 K W comp. mR (51-T₂) 1 x 0.287 (562.03-300) 1-1.4 1-8 comp =- 188 kJ/kg air. So work input to compressor is 188 KJ /kg air - Ane