Questions tagged [combustion]

For questions specifically about the process of burning fuel.

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28 views

What was the first engine to utilise Can-Annular combustion system?

Im doing research on the history and development of combustion systems and cannot find the first engine to utilise the Can-Annular combustion system.
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1answer
78 views

What is the air/fuel mixture ratio in a turbojet engine?

How does it relates to stoichiometry ? What are the possible extinction accidents related to air/fuel mixture ratio ?
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When are pressure-swirl atomizers and airblast atomizers used?

I am a little confused as to when (during T/O, cruise, etc.) and how the combined pressure-swirl atomizer and airblast atomizer is used. Lefebvre writes that "the merits of the pressure-swirl ...
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Does/Can combustion instabilities occur in SCRAM jet?

I was told that combustion occurs at Supersonic speeds in SCRAM jet. So acoustic disturbances/ pressure fluctuations can't travel into incoming jet stream. Does this avoids combustion instabilities in ...
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Turbine engine combustion efficiency [duplicate]

What I read about combustion efficiency of jet engine is ratio of (Th-Tc)/ Th where Th combustion chamber temp and TC exhaust temp. I also read this efficiency reduces with increase in altitude and ...
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Is the combustion process in turbofans and turboshafts different?

According to a journal paper, for a Gnome turboshaft engine, fuel-air equivalence ratio decreases as power output increases. However, for a CFM56 turbofan engine, the opposite trend is true, and ...
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482 views

Can some one please explain to me the purpose of the combustion chamber? [duplicate]

Please, i need some one to explain to me the purpose of the combustion chamber in a jet engine, why do we need to burn the gases to get energy ? the compression does not suffice ?? is it possible to ...
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1answer
1k views

What are the differences between single and double annular combustion chambers?

The combustion chamber of a jet engine may be can type or annular type. Annular type combustion chamber can be SAC (single annular combustion chamber) or DAC (double annular combustion chamber). What ...
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1answer
4k views

What is the difference between single and dual annular combustor?

CFM56 uses single annular and GEnX uses dual annular combustion chamber. somebody please explain with pics.
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2answers
1k views

What is the Fuel-Oxygen ratio for a large turbofan at cruise conditions?

What is the Fuel-Oxygen ratio (by mass) for a large turbofan at cruise conditions? In order to be concrete, I'll just pick an engine at random. I pick the GE90-115B. Okay it's not really random, it'...
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1answer
3k views

How does a turbofan with afterburner continue to function in extreme humidity and rain?

From what I understand, the fan(s) collect(s) and compress(es) air into the compression chambers, where fuel is added to the air & combusted to create an even bigger pressure/thrust, right before ...
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2answers
1k views

What materials are used to make up a combustion chamber? [duplicate]

What type of materials are used to make up the different sections such as the linings of the combustion chambers in a gas turbine engine. Do these type of materials vary for the different types of gas ...
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1answer
2k views

What is the temperature of the air leaving the combustion chamber of a CFM56-5C?

What is the temperature of the air leaving the combustion chamber of a CFM56-5C? I was wondering as I could only find out that the fuel burns at around 1500 Celsius but this can't be the same as the ...
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1answer
494 views

Are flame holders made of a special material other than that used in combustion chamber?

Are the flame holders made of materials which have higher friction coefficients than the combustion chamber in order to create turbulence?
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3k views

How is the correct air speed for fuel combustion obtained at the inlet of the combustor? [duplicate]

Many jet aircraft travel at speed of about Mach .8 which at an altitude of 11 km represents an airspeed of about 300 kt or 150 m/s. If fuel was injected into air at this speed, the mix would just ...
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1answer
970 views

How is flame stabilisation carried out?

How is flame stabilization done in a jet engine combustion chamber? What are the various ways of doing this? What are the challenges/ problems faced?
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3k views

What is the absolute velocity change through compressor+burner?

I thought that the velocity going through a turbojet increased as it went through the compressor and the burner. Intuitively, if the pressure/enthalpy increases, so would the velocity, right? I came ...
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635 views

Why would a jet engine use cannular combustors if the annular design is superior?

Why are cannular type burners used in aircraft engines if annular type have more advantages over it?
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4answers
14k views

Why do gases in the combustion chamber only flow one direction to the gas turbine in a jet engine?

As far as I know from the working principle of jets engines, compressed air in the combustion chamber (or combustion canister) is mixed with fuel. The ignited mixture expands backwards to turn the ...