Brayton cycle combustion process

In summary, combustion of fuel and air in a combustion chamber in a Brayton cycle is idealized by a constant pressure because the open ends of the chamber allow for a known flow rate and any increase in pressure is offset by acceleration through the exhaust. This is in contrast to a diesel cycle, where idealization by constant pressure is necessary due to the increase in pressure from ignition. In the case of the Brayton cycle, idealizing combustion by constant volume would be more logical due to the fixed combustion chamber.
  • #1
ehabmozart
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Why does or how does combustion of fuel and air in a combustion chamber in a brayton cycle is idealized by a CONSTANT pressure. I remember that in a diesel cycle, it was idealized by constant pressure because as P increases by ignition but the volume increase offsets this increase. However, in this brayton cycle case, a combustion chamber is fixed and idealizing combustion by constant volume seems more logical.

Thanks in advance
 
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  • #2
The combustion chamber has open ends where air enters from one end and exit from the other with a known flow rate. As soon as the pressure want to increase in the combustion chamber, the gases are accelerated through the exhaust instead, such that the pressure never increases.
 
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FAQ: Brayton cycle combustion process

1. What is the Brayton cycle combustion process?

The Brayton cycle combustion process is a thermodynamic cycle that is used in gas turbine engines to convert fuel into mechanical energy. It involves compressing air, adding fuel and igniting it, expanding the combustion gases through a turbine, and then exhausting the gases out of the engine.

2. How does the Brayton cycle combustion process work?

The process starts with air being drawn into the engine and compressed to a high pressure. Fuel is then injected and ignited, creating a high-temperature and high-pressure gas. This gas expands through the turbine, causing it to spin and produce mechanical energy. Finally, the exhaust gases are released, and the cycle repeats.

3. What are the advantages of using the Brayton cycle combustion process?

The Brayton cycle combustion process offers several advantages, including high efficiency, low emissions, and a simple design. It also has a high power-to-weight ratio, making it ideal for use in aircraft engines and power generation.

4. What are the limitations of the Brayton cycle combustion process?

One limitation of the Brayton cycle combustion process is that it is not very efficient at low power levels. It also requires a steady flow of air and fuel to maintain the cycle, which can be challenging to achieve in certain conditions. Additionally, the high temperatures and pressures involved can lead to wear and tear on engine components.

5. How is the Brayton cycle combustion process different from the Otto cycle?

The main difference between the Brayton cycle combustion process and the Otto cycle is that the Brayton cycle is an open cycle, while the Otto cycle is a closed cycle. This means that the air and fuel mixture is constantly replenished in the Brayton cycle, while it remains constant in the Otto cycle. Additionally, the Brayton cycle uses a turbine to extract work, while the Otto cycle uses a piston.

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