Computational Fluid Dynamics (CFD) analysis of mixed convection heat transfer enhancement in a channel with complex rotating obstruction

Abstract: In this thesis, a variable speed heat conducting cylinder is positioned in the middle of a rectangular channel with an active flow modification system to demonstrate a numerical study of steady two-dimensional mixed convention heat transfer phenomena. In the current study, the lower wall has a discrete isoflux heater installed while the upper wall is kept at an isothermal low temperature. The Prandtl number of air passing through the channel is held constant at 0.71 while the Reynolds and Grashof numbers are greatly varied for four different cylinder configurations, including (a) channels without cylinders, (b) channels with stationary cylinders, (c) channels with rotating clockwise cylinders, and (d) channels with rotating counterclockwise cylinders. Only the clockwise and counterclockwise rotational setups have a speed ratio variation of 0.5, 1.0, and 1.5. The distribution of streamlines and isothermal lines are used to evaluate the impact on the flow pattern and temperature field, while the local and surface averaged Nusselt numbers are used to analyze the impact on the heat transfer phenomena. The findings show that the Grashof and Reynolds numbers, rotational speed, and cylinder configuration have a significant impact on the flow pattern, temperature field, and heat transfer characteristics.