Mean spherical approximation algorithm and Monte Carlo results for binary multi-Yukawa mixtures /
| Main Author: | |
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| Other Authors: | , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy Link to ProQuest copy |
| Abstract: | An efficient numerical algorithm is given to find the Blum and H0ye mean spherical approximation (MSA) solution for mixtures of hard-core fluids with multi-Yukawa interactions. The initial estimation of the variables is based on the asymptotic high-temperature behavior of the fluid. From this initial estimate only a few Newton-Raphson iterations are required to reach the final solution. This solution is guaranteed to be unique and stable, from a thermodynamic point of view, whenever the fluid appears as a stable, homogeneous phase. A criterion to ascertain whether the solution obtained is stable or not is included in the algorithm. Furthermore, this Yukawa-MSA algorithm can be used in a most simple way to estimate the onset of thermodynamic instability and to predict the nature of the resulting phase separation (whether vapor-liquid or liquid-liquid). Specific results are presented for two binary multi-Yukawa mixtures. For both mixtures, the Yukawa interaction parameters were adjusted to fit, beyond the hard core diameters σ, Lennard-Jones potentials. Therefore, the potentials studied, although strictly negative, included a significant repulsion interval. The characteristics of the first mixture were chosen to produce a nearly ideal solution, while those of the second mixture favored strong deviations from ideality. The MSA algorithm was able to reflect correctly their molecular characteristics into the appropriate macroscopic behavior, reproducing not only vapor-liquid equilibrium but also liquid-liquid separations. The same mixtures were studied through Monte Carlo (MC) simulation for a variety of compositions, densities (in the liquid range) and temperatures. A comparison is made between the theoretical and "experimental" results for configurational energy, pressure and chemical potentials. The latter were determined, in the simulations, through a new implementation of Widom's test particle (or particle insertion) method. This very simple implementation allowed the calculation of chemical potentials at high densities, where the usual implementations tend to fail. An analysis of the standard deviations and of the internal consistency of the MC data is used to confirm the general reliability of the simulation results... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Chemical engineering." |
| Physical Description: | x, 186 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |