# Tag Info

10

They are provided to help damp out combustion instabilities. The main injector uses cooled baffle elements, developed at Glenn in the 1960s to control pressure waves that could destroy the engine. Pressure waves in the space shuttle main engine combustion chamber are also controlled by acoustic cavities. Testing by Glenn engineers determined the ...

7

You can referthis book Modern Engineering for Design of Liquid-Propellant Rocket Engines chapter 4. It depends the on the number of performance parameters such as $C_f, C^*$ and $I_{sp}$. From which the Throat area is calculated. Throat area is usually used as a starting point to have the thrust chamber dimensions. Characteristic length and Contraction ratio ...

7

Restartable hydrogen-oxygen engines like the RL10 (used on the Delta and Atlas upper stages) and J-2 (used on Saturn) use spark ignition. On the J-2, the spark igniter is positioned above the fuel injector face, in a small chamber above the main combustion chamber. It's apparently uncooled and actually operates continuously during engine firing. Presumably ...

5

Anton must really love chemistry or pain. NASA's CEA is a robust tool for analyzing combustion thermo-chemistry which was developed by the same Gordon & McBride mentioned in Anton's answer while they were working at NASA. They also make MATLAB wrappers for the thing, but I'm not sure where to find a publicly available option. It will save you a ...

4

The ACES upper stage (in development at the moment) is being designed to do without an external source of pressurizing gas: Fundamentally IVF is a Hydrogen/Oxygen auxiliary power unit, that uses free boiloff hydrogen and oxygen to generate electricity (eliminating main vehicle batteries), provide autogenous tank pressurization (eliminating most or all ...

4

No, the Centaur with its RL-10 engines requires tank pressurization. Helium Supply and Pressurization System - Helium is the main pressurant used for tank pressurization. Typically, four 26-inch diameter high-pressure helium bottles mounted on the aft bulkhead are used for storage. They are made of a graphite/epoxy composite overwrap enveloping a stainless ...

4

To an old timer like me who was one of the pioneers in much of the rocket engine research during the Saturn V F-1 engine development at Princeton University (around 1966 – 71), I’m glad to see renewed public interest in these topics. My feelings are that the private rocket companies now-a-days are doing some good things with their new designs and strategies. ...

4

From my (probably) similarily rough understanding of L*, it's a minimum size required for propellants to stay long enough in the chamber to mix properly. If the distance is shorter than that, you will experience problems with combustion instability. As such, having a length that's too large is certainly not as bad as too short, although the engine is then ...

3

The reason you can't finish your calculations is that you are missing half of the engine. You are going to have to make some decisions about the nozzle in order to get exhaust velocity. I'll make some decisions for you and show you how to work through it. Your engine's design altitude is going to be 11.8 km. This means that your nozzle exit plane pressure is ...

3

You will need to write a solver for the incomplete combustion of your propellant. This can be done by hand, but I recommend writing a program to implement it. These days, such calculations are primarily done by solving for the maximum entropic state of the system (the system being the mixture of reactants at the chamber temperature & pressure). The ...

3

There are different numbers on this NASA page about Saturn V: Finally, the fuel squirted through 3 700 orifices into the combustion chamber to mix with the oxidizer, which entered through 2 600 other orifices in the injector face If the hole numbers of the question are correct, (1428 Oxidizer holes and (approximately) 1404 Fuel (RP1) holes) the explanation ...

3

'tubes' aren't enough. You want an injector, in order to atomize the fuel and oxidizer and mix them. A simple one is the pintle injector, which has concentric openings for the fuel and oxidizer. Fuel being injected: and oxidizer: Other injectors have lots of openings alternating fuel and oxidizer, like the F-1 engine used in the Saturn V: You also ...

2

Inconel is chosen because it has a much higher melting point than copper, so the engine can be run at a high temperature.

Only top voted, non community-wiki answers of a minimum length are eligible