1. A Brayton cycle uses air and produces a net work of 14000 Btu/s with an inlet state of 60°F, 14.7 psi and a compression ratio of 16. The heat added in the combustion process is 400 Btu/lbm. If the thermal efficiency is 0.547 Determine: Using variable specific heat method
1) The highest temperature in the cycle
2) The mass flow rate of the air
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2. A Brayton gas turbine cycle has two stages of compression and two stages of expansion. The pressure ratio across each stage of the compressor and turbine is 3. The air enters each stage of the compressor at 300K and each stage of the turbine at 1200K. If the efficiency of each compressor is 80% and each turbine is 85% Determine: *using variable specific heat method for*:
Case 1) no regenerator
a) The back work ratio
b) The thermal efficiency
Case 2) a regenerator with 75% effectiveness
a) The back work ratio
b) The thermal efficiency