Content deleted Content added
Keystone18 (talk | contribs) |
m clean up spacing around commas and other punctuation fixes, replaced: , → , |
||
Line 38:
| H=2
| Appearance = Colorless liquid
| Density = {{convert|0.07085|g/cm3|lb/ft3|abbr=on}}<ref>[http://webbook.nist.gov/cgi/fluid.cgi?Action=Load&ID=C1333740&Type=SatT&Digits=5&PLow=.5&PHigh=1.5&PInc=.1&RefState=DEF&TUnit=K&PUnit=atm&DUnit=kg/m3&HUnit=kJ/mol&WUnit=m/s&VisUnit=uPa*s&STUnit=N/m Thermophysical Properties of Hydrogen]
| MeltingPtC = −259.14
| MeltingPt_ref = <ref name="h">[http://www.safety.seas.harvard.edu/services/hydrogen.html ''Information specific to liquid hydrogen''] {{webarchive|url=https://web.archive.org/web/20090717083849/http://www.safety.seas.harvard.edu/services/hydrogen.html |date=2009-07-17}}, harvard.edu, accessed 2009-06-12</ref>
Line 92:
==Uses==
Liquid hydrogen is a common [[liquid fuel|liquid]] [[rocket propellant|rocket fuel]] for [[spacecraft propulsion|rocketry]] application and is used by [[NASA]] and the [[United States Air Force|U.S. Air Force]], which operate a large number of liquid hydrogen tanks with an individual capacity up to 3.8 million liters (1 million U.S. gallons).<ref name="Flynn2004">{{cite book|author=Flynn, Thomas |title=Cryogenic Engineering, Second Edition, Revised and Expanded|url=https://books.google.com/books?id=-XfMBQAAQBAJ&pg=PA401|date=2004|publisher=CRC Press|isbn=978-0-203-02699-1|page=401}}</ref>
In most [[rocket engine]]s fueled by liquid hydrogen, it first [[regenerative cooling (rocket)|cools]] the nozzle and other parts before being mixed with the oxidizer, usually [[liquid oxygen]], and burned to produce water with traces of [[ozone]] and [[hydrogen peroxide]]. Practical H<sub>2</sub>–O<sub>2</sub> rocket engines run fuel-rich so that the exhaust contains some unburned hydrogen. This reduces combustion chamber and nozzle erosion. It also reduces the molecular weight of the exhaust, which can increase [[specific impulse]], despite the incomplete combustion.
| |||