Modeling the dynamic viscosity of associating and polar fluids via the use of density scaling
| Autor: | M. Díaz-Cruz, Ricardo Macías-Salinas, Miguel Angel Flores-Granados, Fernando García-Sánchez |
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| Rok vydání: | 2018 |
| Předmět: |
Chemistry
General Chemical Engineering Relative viscosity Intrinsic viscosity Inherent viscosity General Physics and Astronomy Thermodynamics 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Thermodynamic potential Viscosity Temperature dependence of liquid viscosity Critical point (thermodynamics) 0103 physical sciences Physical and Theoretical Chemistry 010306 general physics 0210 nano-technology Scaling |
| Zdroj: | Fluid Phase Equilibria. 458:16-29 |
| ISSN: | 0378-3812 |
| Popis: | It is well-known that certain dynamical properties such as the dielectric relaxation times and the viscosity of liquids can be graphically superpositioned onto a single master curve as a function of the thermodynamic potential (ργ/T), where T is the temperature, ρ is the density, and γ is a state-independent scaling exponent. We presently applied the aforementioned thermodynamic scaling to the viscosity of typical hydrogen-bonding formers and polar fluids such as water, hydrogen sulfide, ammonia, methanol and an ionic liquid: [bmim][PF6]. Unlike previous studies on density scaling of transport properties, a more suitable reduction and normalization of the viscosity was introduced here in order to obtain improved correlations of viscosity over much wider temperature and pressure ranges encompassing the zero-density limit, the high-density region, the gas-liquid saturation line and the vicinity of the critical point. A calculation procedure is also described here to optimize the value of the scaling exponent γ that ensures the best super-positioning of all experimental isotherms considered for each substance. |
| Databáze: | OpenAIRE |
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