Approximate solutions to the shrinking core model and their interpretation

Fuente: arXiv
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Main Authors: Moreno-Pulido, Cristian, Olwande, Rachael, Myers, Tim, Font, Francesc
Format: Preprint
Published: 2025
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author Moreno-Pulido, Cristian
Olwande, Rachael
Myers, Tim
Font, Francesc
author_facet Moreno-Pulido, Cristian
Olwande, Rachael
Myers, Tim
Font, Francesc
contents The shrinking core model describes the reaction of a spherical solid particle with a surrounding fluid. In this work, we revisit the SCM by deriving it from the underlying physical processes and performing a careful non-dimensionalisation, which highlights the limitations of the commonly used pseudo-steady-state approximation, particularly in liquid-solid systems where fluid and solid densities are comparable. To address these limitations, we derive approximate analytical solutions using a perturbation method that improves upon the pseudo-steady-state model. We also obtain a small-time solution capturing early transient behavior. A semi-implicit finite difference scheme is implemented to solve the full model numerically and benchmark the analytical approximations. We demonstrate that the perturbation solution provides significantly improved accuracy over the pseudo-steady-state model, especially in diffusion-limited regimes. Finally, we propose a simple fitting procedure combining the perturbation with the early-time solutions to estimate physical parameters from experimental data at minimal computational cost.
format Preprint
id arxiv_https___arxiv_org_abs_2507_21042
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Approximate solutions to the shrinking core model and their interpretation
Moreno-Pulido, Cristian
Olwande, Rachael
Myers, Tim
Font, Francesc
Other Condensed Matter
The shrinking core model describes the reaction of a spherical solid particle with a surrounding fluid. In this work, we revisit the SCM by deriving it from the underlying physical processes and performing a careful non-dimensionalisation, which highlights the limitations of the commonly used pseudo-steady-state approximation, particularly in liquid-solid systems where fluid and solid densities are comparable. To address these limitations, we derive approximate analytical solutions using a perturbation method that improves upon the pseudo-steady-state model. We also obtain a small-time solution capturing early transient behavior. A semi-implicit finite difference scheme is implemented to solve the full model numerically and benchmark the analytical approximations. We demonstrate that the perturbation solution provides significantly improved accuracy over the pseudo-steady-state model, especially in diffusion-limited regimes. Finally, we propose a simple fitting procedure combining the perturbation with the early-time solutions to estimate physical parameters from experimental data at minimal computational cost.
title Approximate solutions to the shrinking core model and their interpretation
topic Other Condensed Matter
url https://arxiv.org/abs/2507.21042