Slush hydrogen

Slush hydrogen is a combination of liquid hydrogen and solid hydrogen at the triple point with a lower temperature and a higher density than liquid hydrogen. It is formed by bringing liquid hydrogen down to nearly the melting point increasing density by 16-20% compared to liquid hydrogen [ [http://gltrs.grc.nasa.gov/cgi-bin/GLTRS/browse.pl?1995/TM-106863.html A summary of Slush hydrogen] ]

Production

The continuous freeze technique used for slush hydrogen involves pulling a continuous vacuumover triple point liquid and using a solid hydrogen mechanical ice-breaker to disrupt the surface of the freezinghydrogen. [ [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19970026089_1997043543.pdf Comparision of the continuous freeze slush hydrogen production] ] [ [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780018251_1978018251.pdf Producing Liquid-Solid Mixtures of Hydrogen Using an Auger] ] [ [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690017064_1969017064.pdf 1966 - Preparation and characterization of slush hydrogen and nitrogen gels] ]

*Fuel density 0.085 g/cc
*Freezing Point -259 deg C
*Boiling Point -259 deg C

History

Slush hydrogen was proposed in the 1965 to maximize fuel weight to empty weight [ [http://www.astronautix.com/props/airshlh2.htm Density] ]

ee also

*Compressed hydrogen
*Hydrogen safety
*Metallic hydrogen
*Timeline of hydrogen technologies
*Liquefaction of gases

References