Rocket Engine Combustion Chamber Equations

In summary, the conversation discussed the design of a proper combustion chamber and nozzle for a rocket engine. The participants mentioned the difficulty in finding equations that cover the dimensions of the chamber and suggested using search engines to find information on specific rocket engines and nozzle designs. They also mentioned that NASA Marshall and Rocketdyne have their own proprietary codes for analyzing nozzle designs. AIAA has books on propulsion that may include information on combustion chambers, throats, and nozzles. The participants also provided some information on the dimensions and parameters of the SSME, including its area ratio, chamber pressure, and mixture ratio.
  • #1
FiggyOO
13
0
Good evening all,

I was wondering if anyone would be able to point me in the right direction to equations in regards to designing a proper combustion chamber for a rocket engine, as well as for the throat/De Laval nozzle as well. I've looked around and I can't seem to find anything that covers the actual dimensions of the chamber.
 
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  • #2
I don't think things are just as easy as using equations & feeding numbers for designing purpose.
 
  • #3
This might be useful.

http://www.pwrengineering.com/articles/nozzledesign.htm


NASA Marshall used a program called RAMP to analyze nozzle designs. I would expect Rocketdyne (now part of United Technologies/Pratt & Whitney) used their own proprietary code.

Search Google or other search engine with "SSME","nozzle"

The SSME uses an H2-rich mixture.

AIAA has a number of books on propulsion, including some description of combustion chambers, throats, and nozzles.
 
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  • #4
Thanks, I know there are equations to make a proper combustion chamber though. I know that the chamber needs to be a certain length and diameter in relation to the nozzle.
 
  • #5
One could take a cross-section and simply plot diameter or radius of nozzle as a function of distance from throat.

For SSME -
Area Ratio: 69:1
Chamber Pressure: 2,994 psia
Engine Mixture Ratio: 6.0 (IIRC, mass O2/mass H2)

Dimensions
Length: 168 in.
Diameter: 96 in.

http://www.enginehistory.org/SSME/SSME1.pdf
 
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1. What is a rocket engine combustion chamber?

A rocket engine combustion chamber is a part of a rocket engine where fuel and oxidizer are mixed and ignited to produce hot gases that generate thrust. It is a critical component of a rocket engine and is responsible for converting chemical energy into kinetic energy to propel the rocket.

2. What are the main equations used in a rocket engine combustion chamber?

The main equations used in a rocket engine combustion chamber are the conservation of mass, conservation of momentum, and conservation of energy equations. These equations are used to calculate the flow of fuel and oxidizer, the resulting thrust, and the temperature and pressure within the chamber.

3. How are the combustion chamber equations derived?

The combustion chamber equations are derived using principles of thermodynamics, fluid mechanics, and chemical kinetics. They take into account factors such as the chemical reactions between the fuel and oxidizer, the compressibility of gases, and the heat transfer within the chamber.

4. What are the assumptions made in the combustion chamber equations?

The combustion chamber equations make several assumptions to simplify the calculations. These include assuming the gases are ideal, neglecting friction and heat loss to the walls of the chamber, and assuming steady-state conditions with no changes in the flow properties over time.

5. How are the combustion chamber equations used to optimize rocket engine performance?

The combustion chamber equations play a crucial role in optimizing rocket engine performance. By using these equations, engineers can determine the most efficient fuel and oxidizer ratios, chamber pressure, and nozzle design to maximize thrust and specific impulse while minimizing weight and cost.

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