Wedge shaped protrusions in duct flows for heat transfer enhancement

Understanding the underlying fluid dynamics is essential for the design of ducts and control of flow therein such that better heat transfer efficiency could be achieved. The numerical results of flow through a duct with repeated wedge-shaped protrusions heated from below with the aim to investigate the effect of such protrusions for heat transfer enhancement are presented. Different flow regimes for a two-dimensional flow are identified and the heat transfer enhancement achieved by varying two different geometric parameters of the wedge (blockage and distance between the wedges - pitch) are explained. Three-dimensional linear stability limits and the underlying modes which destabilises the flow are unveiled and the effect of three-dimensionality on the heat transfer behaviour are elucidated. Further, sensitive regions in the flow wherein any modification will be beneficial to amplify instabilities and control these flows for better heat transfer enhancement are discussed.