Lattice Boltzmann modeling with appropriate interface treatment for the transient heat and mass diffusion through multilayered multicomponent materials with irregular boundary

Abstract

Purpose The aim of this research is to promote modeling transient heat and volatile organic compound (VOC) diffusion in multilayered materials with different thermophysical characteristics and irregular interfaces. Although lattice Boltzmann method (LBM) has exhibited considerable promise for steady-state transport, efforts are still needed in accurately addressing flux continuity on interfaces. This research applies and contrasts two methods: the diffuse interface approach, dependent on a smoothness parameter, and the special interface treatment (SIT), which imposes directly flux and field continuity. This is to assess their efficiency, compare with analytical and existing results and illustrate practical use for energy efficiency and indoor air quality control. Design/methodology/approach This study develops a lattice Boltzmann framework to model transient heat and VOC diffusion across multilayer materials with contrasting thermophysical properties and irregular boundaries. Two interface treatments were implemented: (1) the diffuse interface method, which smooths interfacial discontinuities using a tunable thickness parameter and (2) the SIT*, which directly enforces temperature/concentration and flux continuity without additional parameters. Numerical simulations were performed for porous and non-porous assemblies, Sandwich panels and room-scale models. Validation was conducted against analytical solutions and published data to ensure accuracy, robustness and practical applicability ([*]Mohamad et al., 2014). Findings This study demonstrates that while the diffuse interface LBM provides smoother transitions for heat diffusion at regular interfaces, its reliance on a tunable smoothness parameter can obscure sharp gradients and hinder calibration. In contrast, the SIT approach ensures strict continuity of temperature/concentration and fluxes without extra parameters, proving particularly effective for VOC diffusion in multilayer assemblies with abrupt property contrasts and sorption effects. Validation against analytical, numerical and literature results confirms its accuracy for layered materials, Sandwich panels and room-scale problems. Overall, the SIT-based framework offers a practical, reliable tool for optimizing multilayer systems in energy and indoor air applications. Originality/value This study is original in adapting and systematically comparing the diffuse interface method and the SIT within the LBM framework for transient heat and VOC diffusion in multilayer assemblies. While the diffuse interface approach smooths property jumps via a tunable parameter, SIT enforces strict flux and field continuity without extra calibration, offering a robust alternative for VOC transport where abrupt variations dominate. The originality lies in demonstrating SIT's practicality across layered walls, Sandwich panels and room-scale simulations, providing a validated, parameter-free tool with clear relevance to thermal management, energy efficiency and indoor air quality.

Affiliated Institutions

• Pakistan Institute of Engineering and Applied Sciences PK
• Xi'an Jiaotong University CN

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