A simple Brayton cycle uses air as the working fluid, has a pressure ratio of 9.
ID: 1852437 • Letter: A
Question
A simple Brayton cycle uses air as the working fluid, has a pressure ratio of 9.92, and the air enters at 100 kPa, 25 oC. The maximum cycle temperature is limited to 902 oC to prevent damage to the turbine and the compressor efficiency is 88%.
What is the temperature at the end of the compression process?
What is the temperature at the turbine exhaust?
How much heat is added to this cycle?
How much heat is rejected by the cycle?
What is the thermal efficiency of this engine?
Please show your work
Explanation / Answer
= 1.4, Cp = 1.005, Cv = 0.717
T2/T = (P2/P1)^(-1)/
T2/T1 = 1.92625
T2 = 574.0225 K
T3 = 1175 K
T3/T4 = (P3/P4)^(-1)/
T3/T4 = 1.92625
T4 = 609.993 K
Heat Added = Cp(T3 - T2) = 1.005*(1175 - 574.0225) = 603.982 kJ/kg
Work Done = Cp(T3 - T4) = 1.005*(1175 - 609.993) = 567.832 kJ/kg
Compression Work = Cp(T2 -T1)/0.88 = 1.005*(574.0225-298)/0.88 = 315.2302 kJ/kg
Heat rejected = Cp(T4 - T1) = 1.005*(609.993 - 298) = 313.5529 kJ/kg
Cycle Eff = (567.832-315.2302)/603.982 = 41.8227%
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.