Solving Supersonic Combustion Challenges with Detonations

In summary, the conversation discusses how a detonation might propagate outward in all directions equally. There is no way to make a partially spherical wave or planewave out of the shockwave from a detonation, other than blocking one side with a barrier.
  • #1
Clausius2
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Ok. Let's suppose the next imaginary experiment. I encouragely promise that I don't know anything about nowadays supersonic combustion problems. I want to continue with the discussion spread in the "rocket thrust" thread, and what Enigma and Russ Waters said.
There is a supersonic flow at the entrance of combustion chamber, due to the intake of air. Why it does not possible generate a combustion steady wave (i.e. a detonation wave) in the combustion chamber. A weak detonation causes a supersonic flow behind it. I heard the Chapman-Jouguet detonations are possible oftenly.
How could I generate a steady detonation?, I mean a detonation that no moves in the laboratory reference axes.
I have another idea: what about heating the supersonic inlet current?.
The Mach number will decrease, but would it descent below M=1?. In this case would occur a shock wave at the intake?.
 
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  • #2
I think one of the problems with continuous detonation is how to intake air into the fire. As you've pointed out, a detonation creates a supersonic shockwave which spreads outward in every direction away from the center. If the shockwave were stationary relative to the laboratory frame of reference, how would air get in?
 
  • #3
I was not thinking of an spherical shock wave. It would be a part of an sphere, or a plane wave indeed.
I claim to the combustion expertises to try to get rid of my theory giving a powerful reason of why it is not possible (nowadays).
 
  • #4
But I think it is the nature of any detonation to propagate outward in all directions equally. I can think of no way to make a partially spherical wave or planewave out of the shockwave from a detonation, other than blocking one side with a barrier, which would also prevent the inflow of fuel.

Do you know of a way to generate a blast of that shape so that fuel flow will be permitted? I keep trying to imagine one, but I keep running into dead-ends.
 
  • #5
I was thinking like in a burner in which fuel flow and breathing air are mixed coaxially and axilsimmetrically, with the fuel inflow at the centre. It would be a diffusion flame, but now, Is it possible a detonation in such a burner, if the air intake is supersonic?. Would there be enough residence time for burning?. If that is possible, there would be a detonation-steady wave in the laboratory frame, with a flame shape (with a continuous fuel intake).
But the scientists are not dull at all, so I'm waiting an answer telling me this idea is something like a cock and bull story.
 
  • #6
Dear all!
I have a problem in simulating the 1 dimensional znd structure for detonation. I want to use 1 step Arrhenius model for reactio. has anyone done it before? please help me.
Thanks
 

Related to Solving Supersonic Combustion Challenges with Detonations

1. What is supersonic combustion and why is it important?

Supersonic combustion is the process of burning fuel at supersonic speeds, or speeds faster than the speed of sound. It is important because it can lead to more efficient and powerful engines for air and space travel.

2. What are some of the challenges associated with supersonic combustion?

Some challenges include controlling and stabilizing the detonation process, managing high temperatures and pressures, and preventing unwanted vibrations and instabilities in the engine.

3. How can detonation be used to solve these challenges?

Detonation, or rapid and simultaneous combustion, can provide a more efficient and stable combustion process compared to traditional deflagration. It can also help to reduce the formation of pollutants and increase fuel efficiency.

4. What research has been done to improve supersonic combustion using detonation?

There is ongoing research in areas such as optimizing fuel-air mixtures, developing new engine designs, and using advanced computational models to study detonation dynamics. Additionally, experiments are being conducted using alternative fuels and additives to enhance combustion efficiency.

5. What are the potential applications of using detonation in supersonic combustion?

Detonation-based supersonic combustion could have significant applications in hypersonic flight, space propulsion, and even in power generation. It could also help to improve the performance of existing engines and reduce emissions in various industries, such as aviation and energy production.

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