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Phase-field modeling of multicomponent and multiphase flows in microfluidic systems: a review

Somnath Santra (Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India)
Shubhadeep Mandal (Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati, India)
Suman Chakraborty (Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 10 August 2020

Issue publication date: 15 September 2021

628

Abstract

Purpose

The purpose of this study is to perform a detailed review on the numerical modeling of multiphase and multicomponent flows in microfluidic system using phase-field method. The phase-field method is of emerging importance in numerical computation of transport phenomena involving multiple phases and/or components. This method is not only used to model interfacial phenomena typical to multiphase flows encountered in engineering and nature but also turns out to be a promising tool in modeling the dynamics of complex fluid-fluid interfaces encountered in physiological systems such as dynamics of vesicles and red blood cells). Intrinsically, a priori unknown topological evolution of interfaces offers to be the most concerning challenge toward accurate modeling of moving boundary problems. However, the numerical difficulties can be tackled simultaneously with numerical convenience and thermodynamic rigor in the paradigm of the phase field method.

Design/methodology/approach

The phase-field method replaces the macroscopically sharp interfaces separating the fluids by a diffuse transition layer where the interfacial forces are smoothly distributed. As against the moving mesh methods (Lagrangian) for the explicit tracking of interfaces, the phase-field method implicitly captures the same through the evolution of a phase-field function (Eulerian). In contrast to the deployment of an artificially smoothing function for the interface as used in the volume of a fluid or level set method, however, the phase-field method uses mixing free energy for describing the interface. This needs the consideration of an additional equation for an order parameter. The dynamic evolution of the system (equation for order parameter) can be described by AllenCahn or CahnHilliard formulation, which couples with the Navier–Stokes equation with the aid of a forcing function that depends on the chemical potential and the gradient of the order parameter.

Findings

In this review, first, the authors discuss the broad motivation and the fundamental theoretical foundation associated with phase-field modeling from the perspective of computational microfluidics. They subsequently pinpoint the outstanding numerical challenges, including estimations of the model-free parameters. They outline some numerical examples, including electrohydrodynamic flows, to demonstrate the efficacy of the method. Finally, they pinpoint various emerging issues and futuristic perspectives connecting the phase-field method and computational microfluidics.

Originality/value

This paper gives unique perspectives to future directions of research on this topic.

Keywords

Acknowledgements

Shubhadeep Mandal gratefully acknowledges Dr Kaustav Chaudhury and Dr Debabrata DasGupta for insightful discussions.

Citation

Santra, S., Mandal, S. and Chakraborty, S. (2021), "Phase-field modeling of multicomponent and multiphase flows in microfluidic systems: a review", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 31 No. 10, pp. 3089-3131. https://doi.org/10.1108/HFF-01-2020-0001

Publisher

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Emerald Publishing Limited

Copyright © 2020, Emerald Publishing Limited

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