In this study, a new method of enhancing heat transfer in heated channels with purely natural convection flow is presented. Blunt bodies which serve as vortex promoters are introduced into the channel, leading to Kármán vortex streets. Vortex shedding behind cylinders and other blunt bodies leads to a convective mixing of the flow, bringing cooler fluid from the center of the channel to the heated walls. Consequently, the temperature gradient is increased and by that the heat transfer.
The purpose of this work is investigating a parameter field in order to identify optimal geometrical parameters for maximizing heat transfer in heated vertical channels. This is done without adding any active mechanical devices for forced convection, but instead by passive means only, meaning cylinders in particular.
A parameter study comprising geometrical degrees of freedom like diameter and position of the vortex promoting bodies and different wall temperatures is performed numerically, indicating a heat transfer enhancement of up to 47.4% compared to the reference case without vortex promoters. The CFD results are compared to heat delivery measurements and visualization data.
Natural Convection Flow and Heat Transfer Enhancement of a Nanofluid past a Truncated Cone with Magnetic Field Effect