(Solved): A gas turbine engine of single stage compression and expansion processes operates with the air-sta ...

A gas turbine engine of single stage compression and expansion processes operates with the air-standard actual Brayton cycle. The overall pressure ratio is \( 12 / 1 \) and the working temperature is between \( 25^{\circ} \mathrm{C} \) and \( 1300^{\circ} \mathrm{C} \). The isentropic efficiencies of the compressor and turbine are \( 85 \% \), respectively. For this operation, the kinetic and potential energies changes are negligible. Sketch the cycle on a T-s diagram and determine: [CO3:PO3] a) the turbine actual exit temperature (K), b) the back work ratio, c) the thermal efficiency (\%) of the cycle, and d) the new thermal efficiency (\%) of the cycle if a regenerator having an effectiveness of \( 90 \% \) is installed to heat up the air leaving the compressor and briefly explain the changes. CONFIDENTIAL EM/JUL 2022/MEC251 (Given that for air, specific heat capacity, \( C_{p}=1.005 \mathrm{~kJ} / \mathrm{kg} . \mathrm{K}, C_{v}=0.718 \mathrm{~kJ} / \mathrm{kg} . \mathrm{K} \), specific gas constant, \( R=0.287 \mathrm{~kJ} / \mathrm{kg} . \mathrm{K} \) and specific heat ratio, \( k=1.4 \) are constant throughout the cycle). (20 marks)