11. Multifunctional composites by high-pressure spray processesEckhard Weidner, Marcus Petermann, Željko Knez, 2003, pregledni znanstveni članek Opis: A series of spraying processes designed to generate powders and composites using supercritical fluids have been proposed in the past 15 years. In this review, thermo- and fluid-dynamic aspects and engineering principles are discussed and advantages of such technologies are demonstrated. These new techniques display convincing advantages, producing competitive high-quality products with tailor-made properties. Initial industrial applications have been achieved in the production of food products and fine-chemicals. Ključne besede: chemical processing, high pressure technology, micronization, supercritical fluids, particles, powder generation, thermodynamics, fluid dynamics, PGSS Objavljeno v DKUM: 01.06.2012; Ogledov: 2413; Prenosov: 102 Povezava na celotno besedilo |
12. An approach to calculate thermodynamic properties of mixtures including Propane, n-Butane, and IsobutaneJurij Avsec, Koichi Watanabe, 2005, izvirni znanstveni članek Opis: This paper discusses a mathematical model for computing the thermodynamic properties of propane, n-butane, isobutane, and their mixtures, in the fluid phase using a method based upon statistical chain theory. The constants necessary for computations such as the characteristic temperatures of rotation, electronic state, etc. and the moments of inertia are obtained analytically applying a knowledge of the atomic structure of the molecule. The paper presents a procedure for calculating thermodynamic properties such aspressure, speed of sound, the Joule-Thomson coefficient, compressibility, enthalpy, and thermal expansion coefficient. This paper will discuss, for the first time, the application of statistical chain theory for accurate properties of binary and ternary mixtures including propane, n-butane, and isobutane, in their entire fluid phases. To calculate the thermodynamic properties of Lennard-Jones chains, the Liu-Li-Lu model has been used. The thermodynamic properties of the hydrocarbon mixtures are obtained using the one-fluid theory. Ključne besede: statistical thermodynamics, chain theory, mixtures, transport properties, hydrocarbons, isobutane, n-butane, propane, refrigerants Objavljeno v DKUM: 01.06.2012; Ogledov: 2035; Prenosov: 89 Povezava na celotno besedilo |
13. Statistical approach to calculate thermodynamic properties for propaneJurij Avsec, K. A... Watanabe, 2005, izvirni znanstveni članek Opis: The paper describes a mathematical model to compute equilibrium thermodynamic properties in the fluid phase of pure hydrocarbons with the aid of classical thermodynamics and statistical associating chain theories. In the present paper thermodynamic properties for propane, as an example of hydrocarbon substances, are calculated. To calculate the thermodynamic properties of real fluids, models based on the Lennard-Jones intermolecular potential were applied. To calculate the thermodynamic properties of real fluids with the aid of classical thermodynamics, Miyamoto-Watanabe (MW) equations, developed in terms of the Helmholtz energy were used. Analytical results obtained by statistical thermodynamics are compared with the MW model and show relatively good agreement. Ključne besede: statistical thermodynamics, propane, thermodynamic properties, SAFT model, chain theory Objavljeno v DKUM: 01.06.2012; Ogledov: 1757; Prenosov: 83 Povezava na celotno besedilo |
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15. The calculation of thermal conductivity, viscosity and thermodynamic properties for nanofluids on the basis of statistical nanomechanicsJurij Avsec, Maks Oblak, 2007, izvirni znanstveni članek Opis: The paper features the mathematical model of calculation of thermophysical properties for nanofluids on the basis of statistical nanomechanics. Calculation of properties for nanofluids for real substances is possible by the classical and statistical mechanics. Classical mechanics has no insight into the microstructure of the substance. Statistical mechanics, on the other hand, calculates the properties of state on the basis of molecular motions in a space, and on the basis of the intermolecular interactions. The equations obtained by means of classical thermomechanics are empirical and apply only in the region under observation. The main drawback of classical thermomechanicsis that it lacks the insight into the substance of microstructure. Contrary to classical mechanics, statistical mechanics calculates the thermomechanic properties of state on the basis of intermolecular and intramolecular interactions between particles in the same system of molecules. It deals with the systems composed of a very large number of particles. The results of the analysis are compared with experimental data and show a relatively good agreement. The analytical results obtained by statistical mechanics are compared with the experimental data and show relatively good agreement. Ključne besede: statistical thermodynamics, thermophysical properties, viscosity, thermal conductivity, thermodynamic properties, mathematical model, nanofluids, statistical nanomechanics Objavljeno v DKUM: 31.05.2012; Ogledov: 2239; Prenosov: 138 Povezava na celotno besedilo |
16. Analytical calculation of diffusion coefficients and other transport properties in binary mixturesJurij Avsec, Maks Oblak, 2006, izvirni znanstveni članek Opis: The note features the mathematical model of computing binary diffusion coefficient, thermal diffusion factor and viscosity in the real-gas region on the basis of nonequilibrium statistical mechanics. For the analytical calculation of transport properties, we have used the Kihara and Chapman-Cowling model up to the third order. In the presented note we calculated transport properties for mixtures between carbon monoxide and helium. We have developed the new mixing rules for the calculation of transport properties for mixtures. The analytical results obtained by statistical mechanics are compared with the experimental data and they show relatively good agreement. Ključne besede: thermodynamics, statistical thermodynamics, mathematical models, binary diffusion coefficient, thermal diffusivity, binary mixtures Objavljeno v DKUM: 30.05.2012; Ogledov: 2216; Prenosov: 70 Povezava na celotno besedilo |