Mortazavinejad, Seyyed Mohsen, Vinches, Ludwig et Hallé, Stéphane.
2026.
« Evaluating the impact of airflow conditions and fabric thickness on nonwoven thermal resistance via local thermal non-equilibrium ».
International Communications in Heat and Mass Transfer, vol. 180, nº Part 3.
Prévisualisation |
PDF
Hallé-S-2026-34514.pdf - Version publiée Licence d'utilisation : Creative Commons CC BY. Télécharger (1MB) | Prévisualisation |
Résumé
Natural-based nonwovens featuring hollow fibers are investigated for eco-friendly cold-protective clothing due to their biodegradability and low thermal conductivity. However, predicting their thermal resistance under highvelocity airflow requires resolving complex fiber-air heat interactions. The present study evaluates the standard local thermal equilibrium assumption against a local thermal non-equilibrium framework. A twodimensional numerical porous-media model was developed, coupling external turbulent flow with internal laminar flow. The energy formulation was modified via two user-defined functions that integrate radiative thermal conductivity and interfacial convection coefficients for multicomponent hollow fibers. The developed non-equilibrium model demonstrated excellent agreement with experimental measurements. Subsequent comparisons reveal that the validity of the standard thermal equilibrium assumption is regime-dependent and dictated by fluid residence time. Under horizontal airflow (1 m/s), extended residence times permit thermal equilibrium, rendering the equilibrium assumption a suitable approximation. Conversely, vertical flow shortens fluid residence time, inducing a thermal lag between solid fibers and interstitial air. Without capturing this phenomenon, the equilibrium model overestimates convective heat loss, diverging by 23.8% from nonequilibrium predictions for the thickest sample investigated at a 4 m/s vertical flow, and underestimates the insulation benefit of thicker fabrics. By resolving the finite rate of heat exchange, the non-equilibrium framework partitions the individual heat-transfer mechanisms. Utilizing this methodology prevents the under-prediction of thermal resistance in high-wind environments, providing a predictive tool for engineering cold-protective clothing.
| Type de document: | Article publié dans une revue, révisé par les pairs |
|---|---|
| Chercheur(-euse): | Chercheur(-euse) Hallé, Stéphane |
| Affiliation: | Génie mécanique |
| Date de dépôt: | 02 oct. 2026 20:52 |
| Dernière modification: | 02 oct. 2026 23:42 |
| URI: | https://espace2.etsmtl.ca/id/eprint/34514 |
Actions (Authentification requise)
 |
Dernière vérification avant le dépôt |