Overview
This work introduces and evaluates a non-local modeling approach based on bond-based peridynamics for analyzing coupled heat transfer and water flow phenomena within saturated porous media, particularly when phase change occurs. The methodology aims to address complexities associated with multiple interacting physical processes and moving interfaces characterized by abrupt property changes. The formulation is designed to predict the location of the phase interface and to calculate both temperature and pressure distributions within the porous medium under conditions involving pressure-driven water flow.
Research Context
Heat and mass transport in porous media are fundamental processes in various natural and industrial applications. A notable challenge arises when the transported substance undergoes phase changes, such as the freezing and thawing of soils. The predictive modeling of these processes presents difficulties due to the involvement of multiple physical phenomena and the presence of an evolving interface where material properties change discontinuously. Existing challenges in this domain include the need for methodologies that can accurately account for these coupled physico-mathematical complexities.
Approach
The research developed a non-local formulation grounded in bond-based peridynamics. This approach was implemented to model the coupled behavior of heat transport and water flow, explicitly incorporating phase change. The formulation was designed to provide a detailed description of these processes. To verify its accuracy, the proposed methodology was assessed against established solutions:
- Verification against existing analytical solutions for one-dimensional (1D) problems.
- Verification against transient finite element solutions for two-dimensional (2D) problems.
Findings
The developed bond-based peridynamic formulation demonstrated the ability to predict the location of the interface between phases in saturated porous media. It also allowed for the calculation of temperature and pressure distributions throughout the medium, specifically under conditions of pressure-driven water flow. The verification exercises, conducted against both 1D analytical solutions and 2D finite element transient solutions, indicated agreement. This agreement suggests the accuracy of the proposed methodology in capturing these phenomena.
Why This Matters
The detailed coupled description of heat and hydraulic processes provided by this formulation represents a critical step towards the development of a thermo-hydro-mechanical model. Such a model could enable descriptions of phenomena such as the hydrological behavior of permafrost soils and the frost heave phenomenon.