Cryogenic fluids various properties

Cryogenic service is usually defined as temperatures below -100°C (-150°F). Properties of some cryogenic fluids are listed in Table 2.73. Valve materials for operation at temperatures down to -268°C (-450°F) include copper, brass, bronze, aluminum, 300-series stainless steel alloys, nickel, Monel, Durimet, and Hastelloy. The limitation on the various steels falls between 0° and -150°F (-17 and -101°C), with cast carbon steel representing 0°F (-17°C) and 3.5% nickel steel being applicable to -150°F (-101°C). Iron should not be used below 0°F (-17°C). 

Several recent publications from this laboratory on the calculation of thermodynamic properties of cryogenic fluids contain various relations for the determination of entropy, enthalpy, and internal energy. Considerable interest has been expressed about the derivation and application of these equations this interest generally results from the fact that standard texts on thermodynamics are, almost without exception, inadequate in the presentation of material on the calculation of thermodynamic properties. The purpose of this paper is to derive the functions necessary for the calculation of these properties. These derivations are intended to give the reader a better understanding of the methods of calculating thermodynamic properties and thus of the limitations of the tables so produced. 

Equations (la), (2) and (3) were combined and coded for solution on a Burroughs Datatron 205 computer. Properties of the most common cryogenic fluids (oxygen, nitrogen, argon, hydrogen and helium) were expressed as a function of pressure and the problem solved for various. initial pressure conditions. 

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