Questions tagged [combustion-chamber]

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How is the stainless-steel tubing in rocket engines brought into the correct shape?

Some American rocket engines have TCA's (thrust chamber assemblies) built after a certain scheme: A combustion chamber, including part of the nozzle, made of several dozens of stainless steel tubes ...
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4 votes
1 answer
97 views

Discrepancy in local Mach behavior between CEA and other sources

I'm exploring some designs using the NASA CEA (Chemical Equilibrium with Applications) code and I ran into a discrepancy between CEA predicted values for local Mach number at the exit plane and values ...
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4 votes
1 answer
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How is a desired chamber pressure achieved in a liquid rocket engine

Before everyone responds that this has been asked before, I have read through every relevant post I could find here and believe my question has not been clearly covered. I also understand that "...
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1 vote
1 answer
144 views

If building a liquid propellant rocket engine, with bi propellants, how does the dimensions of my Combustion chamber, affect the efficiency?

If building a liquid propellant rocket engine, with bi propellants, how does the dimensions of my Combustion chamber, affect the efficiency ? but also what is the best C* dimensions for an earth sea ...
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4 votes
0 answers
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What equation is being used- chamber pressure v.s. mass flow rate? (Cold-gas thruster)

I am doing a project on cold gas thrusters and have seen a couple of graphs relating chamber pressure against mass flow rate. I can't seem to find the equation that relates these two parameters to ...
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4 votes
1 answer
142 views

Is there a relation between combustion instabilities and chamber pressure?

Is there a relation between the combustion chamber pressure, and either an increase or decrease in both high and/or low frequency combustion instabilities. If so, how has this influenced engine design,...
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17 votes
3 answers
1k views

Is it always one nozzle per combustion chamber and one combustion chamber per nozzle?

When I read about engines like the RD-170 they might have a single turbopump feeding multiple combustion chambers, and each combustion chamber has its own nozzle. Is there, or would it be reasonable ...
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5 votes
1 answer
136 views

Is there a distinct flame-front in a liquid-fuelled rocket combustion chamber?

Liquid fuel and liquid oxidizer are injected at high pressure through small orifices into the 'top' of a rocket's combustion chamber. The intention is that these mix quickly and then burn completely ...
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1 vote
1 answer
786 views

How does one determine the optimal CH4:O2 ratio in a methane-LOX rocket engine?

The SpaceX Raptor uses a 78:22 O2:CH4 ratio. It also has combustion chamber pressures higher than any other rocket engine ever built. My questions are: What's the math / chemistry that determines ...
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5 votes
1 answer
476 views

Does peroxide spontaneously decompose when introduced into hot combustion chambers?

I understand that hydrogen peroxide (HTP) can be decomposed into superheated steam and oxygen using a catalyst, but I haven't been able to find any information on whether or not it will decompose in ...
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2 votes
1 answer
112 views

What is the effect of poorly choosing L* in combustion chamber design?

I am a member of a university rocketry club and we are in the process of designing a liquid rocket engine. One of the previous propulsion leads did the primary conceptual design of this engine in RPA. ...
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5 votes
1 answer
288 views

What is the feasibility of a graphite chamber, nozzle and bell walls

What is the feasibility of using graphite, particularly variants that are easy and affordable to acquire, in a combustion chamber, nozzle and bell as well as nozzle extension? Does it need ...
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3 votes
1 answer
239 views

I don't know where to start with the calculations - rocket engine

Last year I stumbled upon the "How to design, build and test a rocket engine" pdf and since then I have been intrigued by making one (or at least calculating it). So I've been doing some ...
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4 votes
2 answers
228 views

Is it impossible to prevent the combustion instability by injecting the reactants at the choking condition for the liquid rocket engine?

For the liquid rocket engine like LOX/LH2, LOX/methane or LOX/kerosene, the injection velocity fluctuation of fuel and oxidizer (u') can cause the combustion instability sometimes. However, isn't it ...
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3 votes
0 answers
46 views

Where could I find more propellant combustion charts for more different/more broad examples/numbers?

So after asking how I could calculate this kind of propellant combustion charts for different fuels/oxidizers and other ratios and other stuff and getting some really good answers, especially from ...
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5 votes
2 answers
173 views

How to calculate these engine parameters on my own?

I am a space enthusiast and am intrigued mostly by rockets. I recently found a book HOW to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES and have been fiddling around with rocket engine ...
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2 votes
1 answer
193 views

For F1 rocket engine, why propellant holes were not in proportion to the fuel to oxidizer ratio?

I understand that the F1 rocket engine had (approximately) 1428 Oxidizer holes and (approximately) 1404 Fuel (RP1) holes in the injector plate. Since the Oxidizer to fuel ratio was 2.27:1 for the F1 ...
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8 votes
1 answer
719 views

What is the job of the acoustic cavities inside the main combustion chamber?

I am new to rocket engines. I was looking at an image of RS-25 engine's MCC and found these acoustic cavities, and I want to know how they work. Can somebody please explain their working principle? ...
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1 vote
1 answer
132 views

What Constitutes A Combustion Chamber?

I have been reading about combustion chambers and noticed they seem to just be an empty space with the fuel and oxidizer coming in one end and the nozzle at the other end. If the shape below were ...
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4 votes
0 answers
282 views

How to measure the temperature inside a combustion chamber

This question is inspired by How do you determine what the temperature will be in the combustion chamber of a rocket engine? . I wonder how you would mesaure the temperature on the inner surface of ...
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3 votes
2 answers
305 views

Is presssuized gas absent in a turbopump-driven rocket engines?

For RL-10 rocket engines, are the propellent pumps able to provide the propellent without a source of pressurant gas?
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  • 491
3 votes
0 answers
300 views

Problems with shutting off "torch igniter" during the operation of combustion chamber

With reference to the presentation pp 76, where SSME's Augmented Spark Igniter is said to have their flame "On" even after the main combustion chamber ignition, is to prevent the blowback from the ...
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4 votes
1 answer
356 views

How are rocket propellants ignited repeatedly without the ignition source melting

I know that SpaceX's Falcon uses TEA-TEB instead of a physical igniter, but if I remember correctly, NASA has never used hypergolic propellants to start their restart-able engines. How does NASA's (or ...
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3 votes
1 answer
236 views

What is the inner wall of the thrust chamber made of?

With advancements in additive manufacturing, the manufacture of regeneratively cooled thrust chambers is simpler nowadays. Brooklyn based startup Launcher Space Inc. says most 3D printed engines use ...
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5 votes
1 answer
3k views

How are the combustion chamber length and diameter decided

How are the combustion chamber length and diameter decided? Are there any proper formulations or procedures?
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4 votes
1 answer
310 views

Does LOx stay as liquid when entering combustion chamber?

Given the heat from combustion and increased temperature, would the LOx still be in liquid form after emanating from the injector? Or will it instantly transform into gas? Are injectors cooled using ...
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