How does the Brayton cycle relate to jet engines?
The Brayton cycle is the fundamental operating cycle of jet engines, where it describes the process of air compression, fuel combustion at constant pressure, and expansion to produce thrust. This cycle efficiently converts fuel energy into kinetic energy, propelling the aircraft forward.
What are the main components of a Brayton cycle?
The main components of a Brayton cycle are a compressor, a combustion chamber (or combustor), and a turbine. These components work in a sequence that involves compression of air, fuel combustion to add heat, and expansion through the turbine to produce work.
What are the efficiency limitations of the Brayton cycle?
The efficiency of the Brayton cycle is primarily limited by the maximum and minimum temperatures achievable within the cycle, constrained by material limits and design. Additionally, real-world factors like pressure losses, non-ideal compressor and turbine performance, and heat losses further reduce its theoretical efficiency.
How does reheating improve the efficiency of the Brayton cycle?
Reheating improves the efficiency of the Brayton cycle by expanding the working fluid across multiple turbine stages with intermittent reheating in between, which increases the average temperature of heat addition, reduces pressure drops, and hence increases the work output without significantly increasing the specific fuel consumption.
How can the efficiency of a Brayton cycle be improved?
The efficiency of a Brayton cycle can be improved by increasing the pressure ratio, implementing intercooling, reheating, and regeneration. Intercooling reduces compressor work, reheating increases turbine work, and regeneration reduces the heat input needed by transferring exhaust heat to the compressed air before combustion.