Heat transfer and mixing enhancement by using multiple freely oscillating flexible vortex generators

Abstract

h i g h l i g h t s Self-sustained oscillations of flexible vortex generators without any external force except that of the fluid flow. Increase in the oscillations amplitude is obtained by increasing the system degree of freedom. The effect of flaps number and arrangement on heat and mass transfer enhancement applications in static mixers.

Three-dimensional numerical study of heat transfer and mixing enhancement in a circular pipe using self-sustained oscillating flexible vorticity generators

“…After a transient period, the FVG undergo self sustained large displacement oscillation with a frequency approximately equal to their natural frequency. Meanwhile FVG located in rows B and D show small oscillation amplitudes, much more FVG interaction is obtained in rows A, C and E. This observation is particularly relevant with previous results obtained in two-dimensional FVG configurations (Ali et al, 2016) where three successive flaps were needed to reach a self-sustained oscillating system. For future full three-dimensional simulations, it is thus to be expected that adding a sixth tangentially rotated row F may have drastic effect on the oscillation of FVG located in rows B and D. Moreover, it is observed that for a given row, tabs located at the north and south positions always oscillate out of phase with tabs located at the east and west positions.…”

Performance Augmentation of Solar Air Heater for Space Heating Using a Flexible Flapping Guide Winglet

“…There are several published papers about using VGs in forced convective flows. It was concluded that the vibration of elastic VG enhances the convection heat transfer by flo w mixing and breaking the thermal boundary layer adjacent to the heated surfaces [20,21].…”

Flapping dynamics of a flag in the presence of thermal convection

“…Recent studies also suggest novel non-traditional applications of passive flag flapping to reduce turbulent effects (Shen et al 2003), to increase propulsion efficiency (Shoele & Zhu 2013), and to enhance heat transfer in packaged electronics (e.g. Shoele & Mittal 2014;Ali et al 2016). The large amplitude flow-induced oscillations are the basis of some energy harvesting concepts (e.g.…”