🚀 go-pugleaf

In article <C0n6pG.7v4.1@cs.cmu.edu> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
>
>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


This reminds me of an observation I made back when I was building small
amateur rockets.  It seems that an easy way to raise the ISP of a fuel is
to preheat it.  An exothermic reaction consumes some of its output in 
heating the unreacted material up to reaction temperature.  So, liquid Al
at 1000C ought to burn a bit hotter than solid Al at room temperature.  Also,
to pressurize it, you only need something that is a gas at 1000C, like for
example potassium metal (bp 760C, mp 62C).


	Loren Carpenter
	loren@pixar.com