Single-Bubble Rising in Shear-Thinning and Elastoviscoplastic Fluids Using a Geometric Volume of Fluid Algorithm
Ahmad Fakhari1, Célio Fernandes2,3
1Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Rd, Dallas, TX 75390, USA.
Polymers
|August 26, 2023
Summary
This study introduces a new computational method for simulating air bubbles in complex fluids. The algorithm accurately models bubble behavior in Newtonian, viscoelastic, and elastoviscoplastic fluids, enabling diverse industrial applications.
Area of Science:
- Multiphase flow dynamics
- Computational fluid dynamics
- Non-Newtonian fluid mechanics
Background:
- Air bubble motion is critical for heat transfer and material quality.
- Non-Newtonian fluid properties, like viscosity, are significantly affected by air bubbles.
- Accurate simulation of bubble dynamics in complex fluids is challenging.
Purpose of the Study:
- To develop and validate a novel interface-capturing method for multiphase viscoelastic fluid flow.
- To accurately simulate the buoyancy-driven rise of air bubbles in fluids with varying rheological complexities.
- To provide a robust computational tool for applications involving bubble dynamics in complex fluids.
Main Methods:
- Developed a geometric volume of fluid (isoAdvector) approach.
- Utilized a reconstructed distance function (RDF) for interface curvature.
- Employed a piecewise linear interface construction (PLIC) scheme for enhanced accuracy.
- Validated the multiphase viscoelastic PLIC-RDF isoAdvector (MVP-RIA) algorithm with simulations in Newtonian, viscoelastic, and elastoviscoplastic fluids.
Main Results:
- The MVP-RIA algorithm accurately predicted bubble shape and velocity in Newtonian fluids, matching experimental data.
- Simulations in viscoelastic fluids revealed bubble shape transitions to prolate/teardrop forms due to normal stress effects.
- In elastoviscoplastic fluids, bubble deformation was limited for small bubbles, evolving to elongated shapes with multiple tails for larger volumes.
- Achieved accurate results on coarser grids compared to traditional algebraic Volume of Fluid (VOF) methods.
Conclusions:
- The developed MVP-RIA algorithm offers a robust and accurate method for simulating multiphase viscoelastic fluid flow.
- The study demonstrates the algorithm's capability to capture complex bubble deformation and shape transitions in various non-Newtonian fluids.
- This advancement paves the way for improved simulations in industrial applications like bubble columns, polymer processing, and 3D printing.
Keywords:
OpenFOAMelastoviscoplastic fluidgeometric interface capturing approachmultiphase viscoelastic flowsMore Related Videos
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