Доступ предоставлен для: Guest
Портал Begell Электронная Бибилиотека e-Книги Журналы Справочники и Сборники статей Коллекции
Computational Thermal Sciences: An International Journal
ESCI SJR: 0.244 SNIP: 0.434 CiteScore™: 0.7

ISSN Печать: 1940-2503
ISSN Онлайн: 1940-2554

Computational Thermal Sciences: An International Journal

DOI: 10.1615/ComputThermalScien.2019021298
Forthcoming Article

DIRECT NUMERICAL SIMULATION APPLIED TO THE ANALYSIS OF THE CONVECTIVE HEAT TRANSFER ENHANCEMENT IN AN ARC-SHAPED WALL CORRUGATED TUBE

Pamela Vocale
Univeristy of Parma
Fabio Bozzoli
Univeristy of Parma
Andrea Mocerino
Univeristy of Parma
Sara Rainieri
Univeristy of Parma

Краткое описание

The Direct Numerical Simulation approach is here adopted to study the forced convection problem in an arc-shaped wall corrugated tube. This kind of geometry is representative of a widely used passive heat transfer enhancement technique (i.e. wall corrugation) mainly adopted for improving the efficiency of heat transfer equipment. The augmentation mechanism is mainly due to the onset of instabilities in the flow that lead to an early departure from the laminar flow regime. The present work deals with the numerical description of the influence of the flow instabilities on the heat transfer mechanism. The numerical simulations point out that in the unsteady flow regime, due to the formation and disruption of the vortices, the flow loses the symmetry property about the tube axis by developing time dependent velocity component in all the directions. This effect, registered for Re>54, encourages a fluid mixing that greatly enhances the heat transfer mechanism. The augmentation effect is discussed also by adopting the field synergy principle approach which confirms that in the stable regime the convective contribution to the heat transfer mechanism is almost ineffective in a wide region of the domain while the instability reduces the extent of the domain that does not positively contribute to the convective heat transfer.