Questions tagged [combustion-chamber]

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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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0answers
54 views

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 ...
4
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1answer
103 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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3answers
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 ...
5
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1answer
80 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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1answer
152 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 ...
5
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1answer
459 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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1answer
58 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. ...
5
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1answer
234 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 ...
3
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1answer
154 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 ...
4
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2answers
165 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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0answers
40 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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2answers
150 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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1answer
150 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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1answer
596 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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1answer
115 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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0answers
196 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 ...
3
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2answers
273 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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0answers
213 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 ...
4
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1answer
309 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 ...
3
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1answer
214 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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1answer
2k 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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1answer
241 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 ...