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Thu Dec 20, 2012, 10:40 AM

A novel twist on space launches (BBC)

Steven Ashley

To understand why Orbitec’s engines are different, you must first understand how larger liquid-fuel rocket engines – the ones that power astronauts and satellites into orbit – work. At their most basic these rockets have a combustion chamber that’s fed by two pressurised tanks – one of a rocket fuel and one of an oxidiser. When these two are forced into the chamber they mix, ignite and the exhausts are sent at high speed through a nozzle at the end of the rocket, propelling it forward.

At full thrust, these engines get incredibly hot, reaching temperatures upwards of 3,000C (5,400F) or more, hot enough to melt the metal chamber in which the rocket fuel mixes with oxygen and burns. At these extremes, even rockets with sidewalls made of heat-resistant superalloys would fail catastrophically.

To solve this problem, rocket scientists usually incorporate vein-like networks of cooling tubes through the sides of the combustion chamber which contain heat-absorbing liquid fuels that carry off excess thermal energy. The arrangement is like a car’s radiator system with internal coolant ducts arrayed around the outside of the engine core. It is only through this so-called "regenerative cooling" system that the rocket is able to maintain its structural integrity. Although the system works it adds considerable weight, cost and complexity to the engine.

Orbitec’s alternative approach keeps the hot burning gases away from the chamber surfaces altogether. The company’s patented designs create a cyclonic swirl, or vortex, of fuel and oxygen that holds the searing gases and fumes in the very centre of the cylindrical combustion chamber, away from the vulnerable sidewalls.

“Our vortex generator eliminates the high temperatures at the inner surfaces of the engine,” says Martin Chiaverini, principal propulsion engineer at the firm. “You can touch the exterior during lab-test firings and not get burned.”
more: http://www.bbc.com/future/story/20121219-a-novel-twist-on-space-launches

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Reply A novel twist on space launches (BBC) (Original post)
eppur_se_muova Dec 2012 OP
Berlum Dec 2012 #1
phantom power Dec 2012 #2

Response to eppur_se_muova (Original post)

Thu Dec 20, 2012, 01:44 PM

2. I got to see the regenerative cooling infrastructure in the SpaceX engines

Lots Of Tubes. Some of them machined right into the engine assembly itself. Eliminating that subsystem would be a giant simplification.

From a complex systems perspective, I wonder if there are any problems with the vortex system chaotically dropping into some kind of non-vortex attractor. That would be bad.

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