Non-Equilibrium Phase Behavior of Confined Molecular Films at Low Shear Rates

AbstractA Brownian dynamics algorithm described in the companion paper [1] is used to simulate sheared suspensions of particles interacting via a depletion potential. The shear and interaction forces interplay to give a complex non-equilibrium phase diagram: a variety of shear induced agglomerates form at low shear rate, but, for shear rates above a non-equilibrium phase boundary the agglomerates develop interfaces predominantly orientated parallel to the plane of shear gradient and flow.

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Non-equilibrium phase behavior and friction of confined molecular films under shear: A non-equilibrium molecular dynamics study

The Journal of Chemical Physics ◽

10.1063/1.4965829 ◽

2016 ◽

Vol 145 (16) ◽

pp. 164704 ◽

Cited By ~ 12

Author(s):

Sz. Maćkowiak ◽

D. M. Heyes ◽

D. Dini ◽

A. C. Brańka

Keyword(s):

Molecular Dynamics ◽

Phase Behavior ◽

Equilibrium Phase ◽

Molecular Films ◽

Non Equilibrium Molecular Dynamics ◽

Non Equilibrium

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Thermodynamic Analysis of Relaxation Model for Non-Equilibrium Phase Behavior of Hydrocarbon Mixtures

Journal of Physics Conference Series ◽

10.1088/1742-6596/2090/1/012138 ◽

2021 ◽

Vol 2090 (1) ◽

pp. 012138

Author(s):

I M Indrupskiy ◽

P A Chageeva

Keyword(s):

Relaxation Time ◽

Phase Behavior ◽

Relaxation Process ◽

Thermodynamic Analysis ◽

Balance Equation ◽

Equilibrium Phase ◽

Characteristic Relaxation Time ◽

Relaxation Model ◽

Entropy Balance ◽

Non Equilibrium

Abstract Mathematical models of phase behavior are widely used to describe multiphase oil and gas-condensate systems during hydrocarbon recovery from natural petroleum reservoirs. Previously a non-equilibrium phase behavior model was proposed as an extension over generally adopted equilibrium models. It is based on relaxation of component chemical potentials difference between phases and provides accurate calculations in some typical situations when non-instantaneous changing of phase fractions and compositions in response to variations of pressure or total composition is to be considered. In this paper we present a thermodynamic analysis of the relaxation model. General equations of non-equilibrium thermodynamics for multiphase flows in porous media are considered, and reduced entropy balance equation for the relaxation process is obtained. Isotropic relaxation process is simulated for a real multicomponent hydrocarbon system with different values of characteristic relaxation time using the non-equilibrium model implemented in the PVT Designer module of the RFD tNavigator simulation software. The results are processed with a special algorithm implemented in Matlab to calculate graphs of the total entropy time derivative and its constituents in the entropy balance equation. It is shown that the constituents have different signs, and the greatest influence on the entropy is associated with the interphase flow of the major component of the mixture and the change of the total system volume in the isotropic process. The characteristic relaxation time affects the rate at which the entropy is approaching its maximum value.

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