Enhanced Convective Heat Transfer in Enclosures with Internal Heat Sinks

摘要

High Prandtl number fluids have great industrial applications such as in thermal storage devices, and in oil storage and transportation. Natural convection in a square enclosure with differentially heated bottom and top surfaces is numerically studied, using engine oil (Prandtl number 130) as the working fluid. To enhance the heat transfer, cold circular cylinders (heat sinks) were placed in the enclosure. It has found that the surface-averaged Nusselt number at the hot bottom can be potentially enhanced by ～50% by inserting several small heat sinks, leading to improvement in both conduction and convection heat transfer regime. Effects of various sidewall boundary conditions of the enclosure were also studied. For the enclosure with adiabatic sidewalls, different flow structures were obtained when locations of cylinders were varied along the horizontal centerline of the enclosure.