Rocket propellants cryogenic liquids

In organizing the symposium, we made the usual division into solid and liquid rocket propellants. Most readers no doubt already know the relative merits of solid vs. liquid systems—viz., the instant readiness of solids (compared with cryogenic liquids), their higher density (important in volume-limited systems), and the relative simplicity of rocket construction liquids offer easy variation in thrust level and the attainment of higher specific impulses, the latter because physical separation permits the use of fuels and oxidizers that would be incompatible if premixed. 

A Liquid Air Device for Cooling the Wearer of a Totally Enclosed Liquid Rocket Propellant Handler s Suit (4) 196 Pressurized Cooldown of Cryogenic Transfer Lines (4) 378... 

Dilution of Cryogenic Liquid Rocket Propellants During Pressurized Transfer... 

Aerospace Industry AppUcations. NASA s space program utilizes cryogenic liquids to propel rockets. Rockets carry liquid hydrogen for fuel and liquid oxygen for combustion. Cryogenic hydrogen fuel is what enables NASA s workhorse space shuttle to get into orbit. Another application is using liquid helium to cool the infrared telescopes on rockets. 

From Table I we may observe that the theoretically high propellants involve the use of the cryogenic fluids liquid oxygen, liquid hydrogen, and liquid fluorine. Some obstacles encountered in the development of rocket propellant systems possessing a higher than LOX-gasoline systems are [5] ... 

Combustion temperatures, as indicated in Table I, range from 4000-8000 F. Consequently data on behavior of the propellant at the high temperatures and pressures encountered are necessary in order to evaluate its performance as a coolant. The preheating of the coolant fuel or oxidant also improves the rocket motor efficiency. Cryogenic liquids, particularly the hydrogen—oxygen system, serve well as coolants. 

G. R. Kinney, High energy liquid propellants for rockets," 1958 Cryogenic Engineering Conference Proceedings. 

S. Greenfield, "Dilution of cryogenic liquid rocket propellants during pressurized transfer," 1957 Cryogenic Engineering Conference Proceedings. 

The curves in Fig. 4 were developed to illustrate the general relation between Insulation Performance Factor R and staging time for the liquid hydrogen tank of a 30,000 lbs propellant system. This vessel with 6,000 lbs of usable capacity, might be considered typical of cryogenic rocket tankage. The assumptions used are listed on the figure however, some comment about them is in order. 

In an age of rockets and space travel, there is a constant demand for new and stronger propellants. These are classified into cryogenics and storable liquids and characterized by the specific impulse ( /J which is the thrust per unit mass flow of fuel and by convention reported in units of seconds (see Table 14.5). The thrust depends on the combustion temperature and the exhaust and combustion chamber pressures, Pe and Pc, respectively. 

Although cryogenics has been used in rockets since the 1930s, the first large-scale use occurred during World War II in the V-2 rocket, which was propelled with alcohol and liquid oxygen. These unmanned weapons launched the beginnings of modern rocketry and eventually man s entry into space. 

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