Large-eddy simulations of flow and heat transfer in heated concentric annulus with inner cylinder rotation

Kurzfassung

Results from large-eddy simulations are reported for the flow and heat transfer in the annular gap between two concentric cylinders with the outer cylinder stationary and the inner cylinder rotating about its longitudinal axis. The objective of the study was to document the effects of destabilizing rotation on the turbulent transport of heat and momentum. The inner cylinder was heated by applying a constant heat flux while the conditions at the outer wall were adiabatic. Results were obtained for a stationary inner cylinder to serve as baseline for isolating the effects of rotation, and for the inner cylinder rotated at two different rotation numbers viz. 0.21 and 0.86. The Reynolds number was set at 9000 for all cases. With the outer cylinder stationary and the inner cylinder rotating, the effects of rotation are to destabilize the turbulence leading to enhanced mixing and significant increase in wall shear stress and Nusselt number. Additional effects include the displacement from each other of the points where the Reynolds stresses and the corresponding rates of strain are zero, and the non-alignment of their respective directions. These and other results reported herein provide a useful contribution to the very limited literature on heated turbulent flows destabilized by rotation, and can serve as benchmark to aid in the development and validation of turbulence closures for engineering applications.