Question

The incorporation of intercooling system between low-pressure and high-pressure compressors of Brayton cycle

• A. Increases the thermal efficiency and decreases the net work output
• B. Increases both thermal efficiency and net work output
• C. Decreases both thermal efficiency and net work output
• D. Decreases the thermal efficiency and increases the net work output

Hint:

Intercooling in the Brayton cycle reduces the compression work, leading to better net work output but lower thermal efficiency.

Answer 1

The Correct Option is D

Step 1: Intercooling in Brayton cycle
Intercooling is a process used in the Brayton cycle where the air between the two stages of compression is cooled. This reduces the work required by the second compressor stage, leading to lower power consumption.
Step 2: Effect on thermal efficiency
While intercooling increases the work output by reducing the compressor work, it actually decreases the thermal efficiency of the cycle. This is because cooling the air between stages increases the temperature gradient, which is detrimental to thermal efficiency.
Step 3: Effect on work output
By reducing the work required to compress the air in the second stage, it allows more energy to be available for expansion in the turbine, thereby increasing the net work output of the cycle. Conclusion
The correct answer is Option (4) because intercooling decreases thermal efficiency but increases the net work output of the Brayton cycle.