Characterization of heat transfer enhancement for an oscillating flat plate-fin. (February 2020)

• Record Type: Journal Article
• Authors: Rahman, Aevelina; Tafti, Danesh
• Is Part Of: International journal of heat and mass transfer. Volume 147(2020)
• Publication Date: 2020-02
• Subjects: Oscillating flat plate-fin -- Low Reynolds number -- Heat transfer enhancement -- Plunge velocity; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2019.119001
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Infinitesimally thin plate-fin vibration is investigated at Re = 100, Pr = 0.71. Study covers 0.25 ≤ k ≤ 16 and 0.03 ≤ h ≤ 8 giving plunge velocities 0.25 ≤ kh ≤ 4. Nusselt number shows strong dependence on kh only, not on individual k and h . Nusselt number ( Nu ) increases monotonically with kh. Nusselt number is parameterized as a function of kh . Abstract: Heat transfer augmentation is of paramount importance in energy transfer and storage systems and the idea of using the inherent vibrations in a system to enhance heat transfer needs to be thoroughly researched upon. The current study numerically investigates an infinitesimally thin plate-fin undergoing forced oscillations over a range of amplitudes and frequencies in the presence of an approach flow. Reduced frequencies of 0.25 ≤ k ≤ 16 and plunge amplitudes of 0.03125 ≤ h ≤ 8 are investigated at Re = 100 and Pr = 0.71. It is shown that the combined effect of frequency and amplitude on heat transfer enhancement can be accounted for as a single parameter "plunge velocity" (0.25 ≤ kh ≤ 4) instead of the individual frequency and amplitude values. For kh > 0.5 a significant increase in Nusselt number ( Nu ) is observed compared to a stationary plate. With increasing kh or more vigorous oscillations, the increase in Nu becomes more prominent and similar trends and comparable magnitudes were observed for a constant kh value. Unlike the hydrodynamic counterpart of the study, both Leading Edge Vortices (LEVs) and Trailing Edge Vortices (TEVs) are found to act positively to induce enhanced heat transfer on the plate. Finally, the dependence of heat transfer augmentation on the frequency and amplitude of vibration is quantified with a simple parameterization for a plate-fin in a fluid medium.