A General Expression for the Ordered-Packed Volume Fraction of Hard Spheres of Different Diameters

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• 作者：Cyrus Ghotbi and Juan H. Vera
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2002
• 出版时间：March 6, 2002
• 年：2002
• 卷：41
• 期：5
• 页码：1122 - 1128
• 全文大小：70K
• 年卷期：v.41,no.5(March 6, 2002)
• ISSN：1520-5045

文摘

An expression is proposed to evaluate the ordered-packed volume fraction of hard spheres ofunequal diameters in multicomponent mixtures. This value can be used with different mixingrules and with any one-component hard-sphere equation of state (EOS) meeting the correctclose-packed limit. It is shown that the new method improves the results produced byconventional mixing rules for the individual radial distribution functions (RDFs) at contact valueof hard-sphere mixtures. Particular attention is given to the case of the large diameter ratioespecially when the larger spheres are at low concentration. Based on the observation that, ina binary mixture, the value of the RDF at contact value of the larger spheres approaches thevalue of the RDF at contact value of a one-component hard-sphere fluid, the proposed expressionis used to correct the RDF at contact value of a pure hard-sphere fluid in the Santos et al.mixing rule. The EOS obtained by combining the Ghotbi-Vera one-component EOS with thecorrected Santos et al. mixing rule is used to predict different thermodynamic properties, andthe results are compared with the computer-simulated data.