Diffusivities of an Equimolar Methane–Propane Mixture Across the Two-Phase Region by Dynamic Light Scattering

Piszko M, Giraudet C, Fröba AP (2020)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2020

Journal

International Journal of Thermophysics Springer Verlag (Germany)

Book Volume: 41

Article Number: 102

Journal Issue: 7

DOI: 10.1007/s10765-020-02680-1

Abstract

The present contribution examines the accessibility of diffusivities across the two-phase region of an equimolar methane–propane mixture for dynamic light scattering (DLS) experiments. Heterodyne DLS experiments and theoretical calculations of the Rayleigh ratio were performed at 125 different thermodynamic states including the gas, liquid, supercritical, and the two-phase region. The present measurements document that two diffusivities can be determined simultaneously in the liquid state and saturated liquid phase for temperatures and pressures which correspond to densities larger than 1.15 times the critical density. Based on a rigorous assignment of the signals detected in this work, the slow and fast diffusivities could be associated with the Fick and thermal diffusivities. For all other thermodynamic states, a single hydrodynamic mode or signal was obtained experimentally. With the help of theoretical Rayleigh ratios as well as from the general behavior of the diffusivities as a function of temperature and pressure, the signals were identified to be related to the Fick diffusivity in the supercritical state and to a mixed diffusivity in the gas state and the saturated vapor phase. The results are discussed in connection with the behavior of the diffusivities along certain paths in the pressure–temperature projection of the phase diagram of the mixture.

Authors with CRIS profile

Maximilian Piszko Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Cédric Giraudet Erlangen Graduate School in Advanced Optical Technologies (SAOT) Andreas Paul Fröba Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP)

Additional Organisation(s)

Erlangen Graduate School in Advanced Optical Technologies (SAOT)

Related research project(s)

Accurate determination of binary gas diffusion coefficients by using laser-optical measurement methods and molecular dynamics simulations April 1, 2017 - March 31, 2020

How to cite

APA:

Piszko, M., Giraudet, C., & Fröba, A.P. (2020). Diffusivities of an Equimolar Methane–Propane Mixture Across the Two-Phase Region by Dynamic Light Scattering. International Journal of Thermophysics, 41(7). https://doi.org/10.1007/s10765-020-02680-1

MLA:

Piszko, Maximilian, Cédric Giraudet, and Andreas Paul Fröba. "Diffusivities of an Equimolar Methane–Propane Mixture Across the Two-Phase Region by Dynamic Light Scattering." International Journal of Thermophysics 41.7 (2020).

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