Viscosity calculation of supercritcal gases based on the modified Enskog theory

ISRN Physical Chemistry

2012

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For thermodynamic performance to be optimized, particular attention must be paid to the fluid's thermal pressure coefficients and thermodynamics properties. A new analytical expression based on the statistical mechanics is derived for thermal pressure coefficients of dense fluids using the intermolecular forces theory to be valid for liquid lithium as well. The results are used to predict the parameters of some binary mixtures at different compositions and temperatures metal-nonmetal lithium fluid which agreement with experimental data. In this paper, we have used newly presented parameters of analytical expressions based on the statistical mechanics and predicted the metal-nonmetal transition for liquid lithium. The repulsion term of the effective pair potential for lithium shows well depth at 1600 K, and the position of well depth maximum is in agreement with X-ray diffraction and small-angle X-ray scattering.

Section: Resultsmentioning

confidence: 99%

Calculation of Thermal Pressure Coefficient of Lithium Fluid by pVT Data

ISRN Physical Chemistry

2012

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“…In this paper, the accurate thermal pressure is used for the evaluation of the internal pressure of dense fluids using the speed of sound theory . Agreement with experimental thermal pressure coefficient data is shown to be, in general, quite good.…”

Section: Introductionmentioning

confidence: 95%

A New Regularity for Internal Pressure of Dense Fluids

2006

J. Phys. Chem. B

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In this paper, we derive a new regularity for dense fluids, both compressed liquids and dense supercritical fluids based on the Lennard-Jones (12-6) potential function and using speed of sound results. By considering the internal pressure by modeling the average configurational potential energy, and then taking its derivative with respect to volume, we predict that isotherm [(partial differential E/partial differential V)(T)/rhoRT]V(2) is a linear function of rho(2), where E is the internal energy, (partial differential E/partial differential V)(T)) is the internal pressure, and rho = 1/V is the molar density. The regularity is tested with experimental data for ten fluids including Ar, N(2), CO, CO(2), CH(4,) C(2)H(6), C(3)H(8), C(4)H(10), C(6)H(6), and C(6)H(5)CH(3). These problems have led us to try to establish a function for the accurate calculation of the internal pressure based on speed of sound theory for different fluids. The results of the fitting show limited success of the pure substances. The linear relationship appears to hold from the lower density limit at the Boyle density and from the triple temperature up to about double the Boyle temperature. The upper density limit appears to be reached at 1.4 times the Boyle density. The results are likely to be useful, although they are limited.

“…The principle of corresponding states calls for reducing the thermal pressure at a given reduced temperature and density to be the same for all fluids. The leading term of this correlation function is the thermal pressure coefficient of perfect gas, which each gas obeys in the low density range [31,32]. In this paper, we drive an expression for the thermal pressure coefficient of R11, R13, R14, R22, R23, R32, R41, and R113 dense refrigerants using the linear isotherm regularity [18,28].…”

Section: Resultsmentioning

confidence: 99%

Calculation of Thermal Pressure Coefficient of R11, R13, R14, R22, R23, R32, R41, and R113 Refrigerants by pVT Data

Advances in Physical Chemistry

Farzad

2013

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For thermodynamic performance to be optimized particular attention must be paid to the fluid's thermal pressure coefficients and thermodynamic properties. A new analytical expression based on the statistical mechanics is derived for R11, R13, R14, R22, R23, R32, R41, and R113 refrigerants, using the intermolecular forces theory. In this paper, temperature dependency of the parameters of R11, R13, R14, R22, R23, R32, R41, and R113 refrigerants to calculate thermal pressure coefficients in the form of first order has been developed to second and third orders and their temperature derivatives of new parameters are used to calculate thermal pressure coefficients. These problems have led us to try to establish a function for the accurate calculation of the thermal pressure coefficients of R11, R13, R14, R22, R23, R32, R41, and R113 refrigerants based on statistical-mechanics theory for different refrigerants.