View Full Version : Gelled rocket fuel

2009-Jan-22, 02:53 PM
An article from R&D Magazine (http://www.rdmag.com/ShowPR.aspx?PUBCODE=014&ACCT=1400000101&ISSUE=0901&RELTYPE=MS&PRODCODE=00000000&PRODLETT=GT&CommonCount=0)

Engineers and food scientists are teaming up to develop a new type of gelled fuel the consistency of orange marmalade designed to improve the safety, performance and range of rockets for space and military applications.

"This is a very multidisciplinary project," said Stephen Heister, the Purdue Univ. professor of aeronautics and astronautics who is leading one of two teams on the project, which is funded by the U.S. Army Research Office.

Gels are inherently safer than liquids because they don't leak, and they also would allow the military to better control rockets than is possible with solid fuels now used. Motors running on gelled fuels could be throttled up and down and controlled more precisely than conventional rockets that use solid propellants, Heister said.

"You can turn the engine on and off, you can coast, go fast or slow," he said. "You have much greater control, which means more range for missiles. The gelled propellants also tend to have a little more energy than the solid propellants."

Gelled fuels also could be used in thrusters to position satellites and on NASA space missions.

2009-Jan-22, 06:49 PM
It's one approach. Using solid fuel motors throttled by pumping in a liquid catalyst works, too, although not much testing has been done.

Are the gels combined, as in a hypergolic mixture?

2009-Jan-23, 06:07 AM
Gelled propellants were mentioned in the most recent edition (2001) of Sutton's Rocket Propulsion Elements. It's nice to see that someone's trying to put it into practice.

2009-Jan-23, 06:01 PM
Are the gels combined, as in a hypergolic mixture?
That was mentioned in the article.

What I would like to know is how does the gel get to the injectors. Are they fluid enough or dynamic enouth that they can get them to perform in the tank as a fluid, or is there going to be some residue clinging to the sides?

2009-Jan-23, 07:27 PM
A weakly-gelled fluid might damp slosh without the complexity and mass penalty of baffles, eliminate the need for ullage rockets, and still be pumpable. Could be good for rockets that are higher performance than solids and which might need to sit around in freefall for an extended time.

I honestly don't see them as being inherently safer, though. They don't leak? They certainly will leak, under the pressures required to make them flow at high rates. They might even tend to hide leaks until a system is pressurized. And if spilled, they'll...well, stick around, rather than quickly evaporating like LOX. Imagine cleaning toxic, strongly oxidizing goo out of every crevice of a vehicle and launchpad after a problem...

Ara Pacis
2009-Jan-24, 07:03 AM
Can we create carrier compounds for LH2 and LOX that can be densely saturated and in gel form? Call them HyGel and Gellox.

2009-Jan-24, 09:37 AM
Encyclopedia Astronautica (http://www.astronautix.com/engines/lr87.htm) lists an engine that operated on a smiler principles, but they ran into problems with stability.
On a side note, I have used Astronautica as a source when debating Apollo Hoax Conspiracy Theorists, what's the general consensus on its accuracy?