On flexible rectangular strip height on flat plate heat convection
International Journal of Heat and Mass Transfer
Flexible turbulence generator, Heat transfer augmentation, Turbulence
A 0.1 mm thick and 12.7 mm wide (W) rectangular flexible strip is experimentally investigated for its effectiveness in boosting the convective cooling from a heated flat plate in a wind tunnel. Three strip height, 25.4 mm, 38.1 mm and 50.8 mm, were explored at a 10 m/s wind, and a Reynolds number of 8500, based on the strip width. The heat transfer results are expressed in terms of Nusselt number normalized by the corresponding unperturbed reference case (Nu/Nuo). To uncover the physics behind the heat transfer enhancement, the turbulent flow characteristics were detailed via a 3D hotwire probe. The 25.4 mm-high strip generated vortex structures closest to the surface, and the largest near-surface-downwash velocity. These attributes result in a better mixing, and thus, heat removal. Therefore, the 25.4 mm-high strip provides the highest Nu/Nuo, with a peak value of approximately 1.76 at 9 W downstream, 0.26 larger than that of the 50.8 mm-high strip.
Yang, Yang; Ting, David S.K.; and Ray, Steve. (2020). On flexible rectangular strip height on flat plate heat convection. International Journal of Heat and Mass Transfer, 150.