MD simulations and excess entropy scaling for the transport properties of dense HFEs

0575728 - ÚT 2024 IT eng A - Abstrakt
Aminian, Ali - Vinš, Václav
MD simulations and excess entropy scaling for the transport properties of dense HFEs.
22nd EUROPEAN CONFERENCE ON THERMOPHYSICAL PROPERTIES. Venice, 2023. s. 168-168. ISBN 9791221042207.
[European Conference on Thermophysical Properties /22./. 10.09.2023-13.09.2023, Venice]
Grant CEP: GA ČR(CZ) GA22-03380S
Institucionální podpora: RVO:61388998
Klíčová slova: transport properties * refrigerants * MD simulations * excess entropy scaling
Obor OECD: Thermodynamics
https://www.ectp2023.eu/book-of-abstracts

Low GWP HydroFluoroEthers (HFEs) are appropriate for electronic cooling and have the potential to be used in the air-conditioning systems. However, their transport properties need to be examined in the dense fluid region. Therefore, we report, validate, and test quantum mechanically-derived force fields and we used equilibrium and non-equilibrium MD simulations for the transport properties. The fractional Stokes-Einstein (SE) relation was tested to scale the predicted self-diffusion coefficient vs viscosity in the form of (DT-1) ∝ (1/η)s, with s ranges between ≈ 0.89 and 0.92 for the HFE-7000 to -7500 in the reduced density range of ρσ3=0.56-0.75. The excess entropy scaling of the transport coefficients were performed via the formula Г/Г^0=exp(〖aS〗^ex/kT), with Г^0 being the dilute term, for the saturated and dense fluid properties. The formulation was tested for different HFOs, HFCs, and HFEs. The saturation entropies were used for the saturated properties predictions. Three general entropy scaling formula were developed for saturated and dense phases for the dynamic viscosity (η) of several refrigerants, but the three heat conductivity (k) formulas need to be substance-specific valid for the saturated and dense phases. Based on the comparisons with the experimental data (partly are mentioned in the REFPROP v.10), an estimated average error of 15% for the dense liquid and 37% for the dense gas included supercritical (SC) region of heat conductivity, while 19% for the dense liquid viscosity, 22% for the dense gas viscosity included SC fluid, and 45% up to supercritical region for the saturated viscosity were obtained.
Trvalý link: https://hdl.handle.net/11104/0349489