🚀 go-pugleaf

-From: Nick_Janow@mindlink.bc.ca (Nick Janow)
-Subject: Re: Aluminum as Rocket Fuel?
-Date: 2 Jan 93 20:35:31 GMT
-Organization: MIND LINK! - British Columbia, Canada

-0004244402@mcimail.com (Karl Dishaw) writes:

-> How's liquid Al going to work in the combustion chamber?
->
-> --forming fine droplets will require a new injector plate--how did that
-> work for the Li-F rocket Bruce mentioned?  What kind of surface tension
-> does LAl have?  How small would we have to get the droplets to be?

-Depending on the reaction chamber and throat material and conditions, it
-might be possible to use ultrasonics to break the aluminum into fine
-droplets.

-Hmmm, I vaguely that there are ways to make ultrasonic "whistles".  I don't
-know if this could be applied to the injection system, but if it could, it
-would at least not require an electrical power source.  It does sound complex
-though; hopefully existing injection technology will produce droplets of
-sufficiently small size.

There's a diagram on the wall in the building where I work, depicting the
formation of metallic powders. A narrow stream of liquid metal is injected
into a chamber, along with several intersecting high-speed jets of inert gas.
The physics of interacting jets causes turbulence which tears the stream
of metal apart. First the liquid metal breaks up into streamers, several
times as long as they are wide, then the streamers break up into individual
droplets, which eventually solidify.

The first part of this process could be used to form a fine mist of liquid
aluminum, presumably using oxygen instead of inert gas. The metal and gas
are introduced through different openings, which should help to prevent
buildup of oxide on the injectors.

If you want a more advanced reusable engine, you probably need to bring
along a supply of inert gas to blow the molten aluminum out of the
injectors as part of the shutdown process.

John Roberts
roberts@cmr.ncsl.nist.gov