The Impact of Collisions on Heat Transfer in a Particle-Laden Shearless Turbulent Flow
Notice bibliographique
Résumé
mental investigation for decades.On the other hand, particleparticle collisions play a significant role in particulate turbulent flows even in relatively diluted suspensions.The effect of collision has been under investigation since the state-of-theart work of Saffman [1].For instance, collisions between water droplets in clouds are a necessary condition for precipitation formation from cloud droplets and ice crystals, while, particle-particle collisions have a profound impact on the onset and evolution of sandstorms [2].In these processes, the background turbulence of the carrier flow favors inter-particle collisions.The mechanisms of the collision rate enhancement by background turbulence have only become clear in the past few years, and the underlying physics is currently qualitatively well understood, although quantifying the rate of small particles collisions suspended in a turbulent flow may require more advancement.As a pioneering work on the collision effect in particle-laden turbulent flows, Saffman et al., developed the theory of collision of water droplet in cloud physics and they could formulate the droplet collision rates for identical small low-inertial droplets in terms of droplet dimension and turbulence characteristics (the rate of turbulent kinetic energy dissipation and the kinematic viscosity of fluid ).Their findings suggested that the collision frequency of the small droplet suspended in clouds is independent of droplet properties [1].However, in the subsequent works like the work of Sundaram et al., it was found that droplet properties also influence the collision rate.The results of Sundaram et al., showed that particle parameters such as particle response time, number density and size can impact collision frequency as well as background turbulence.They showed the significant dependency of the collision rate on the droplet Stokes number [3].There have also been detailed theoretical investigations of the collision rate, a particularly effective description of the collisionrate enhancement in terms of a stochastic model for the prob-Abstract -In this research, we undertake an investigation of a turbulent flow seeded with heavy inertial particles, employing Eulerian-Lagrangian point-particle direct numerical simulations in the twoway coupling regime.The primary objective of our investigation is to assess the influence of inter-particle collisions on heat transfer within the time-evolving thermal mixing layer that develops between two regions with distinct temperatures in a homogeneous and isotropic turbulent flow.Our findings encompass a range of Stokes numbers spanning from 0.2 to 3, while maintaining a thermal Stokes number to Stokes number ratio of 4.43, at a Taylor microscale Reynolds number up to 124.Our results reveal that particle collisions tend to diminish the correlation between particle temperature and velocity, consequently leading to a marginal reduction in the average heat transfer when compared to a collisionless regime at higher Stokes numbers.
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Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
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