کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
201323 | 460544 | 2013 | 4 صفحه PDF | دانلود رایگان |
Many cubic equations of state have attractive terms that are products of a density function and a temperature function, the so-called alpha function. By making the alpha function substance-specific – usually by letting it depend on the acentric factor – reasonably good representations of the thermodynamic properties can be achieved for many substances. This approach, however, does not always work well for hydrogen and hydrogen-containing mixtures. It is shown in this work that, for hydrogen, an alpha function can be reasonably defined in the temperature range 30–300 K only, provided that the densities are not too high. For higher temperatures or for modeling liquid hydrogen it is necessary to introduce corrections for soft repulsion into the hard-sphere terms of the equations of state.
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• The alpha function of cubic EoS is computed for hydrogen from reference data.
• For hydrogen, the alpha function cannot be defined at all temperatures and densities.
• The alpha function should not be fitted to the acentric factor of hydrogen.
• EoS covering wide density and temperature ranges need to account for soft repulsion.
Journal: Fluid Phase Equilibria - Volume 352, 25 August 2013, Pages 93–96