The Brayton cycle is known as the constant

• A. temperature cycle.
• B. volume cycle.
• C. pressure cycle.
• D. mass cycle.

Answer: (C)

The key idea here is that heat is added to the working fluid at nearly constant pressure. In the ideal Brayton (air‑standard) cycle, air is compressed, then fuel is burned in the combustor while the flow remains at essentially the same pressure. The combustor is part of the open, continuous flow path, so the pressure doesn’t change much as temperature rises. After heating, the gas expands through the turbine, producing work and dropping in temperature and pressure along the way. Because the energy addition happens at roughly constant pressure, the Brayton cycle is described as a constant-pressure cycle. Real engines have small pressure losses, but the principle remains the same.