Abstract
Large-eddy simulations (LES) of centrifugal convection in a closed rotating cavity with different thermal boundary conditions are presented for Rayleigh numbers (Ra) 107∼109. Previous results for radial convection with a positive radial temperature gradient and for axial convection with low Ra are confirmed. For axial convection, turbulence develops in the core flow at Ra=109, but is considerably weaker than the turbulence for the radial and mixed convection. In mixed convection, the mean core temperature shows little radial variation as in radial convection, but has a significant axial temperature gradient as in axial convection. Compared to the radial and axial convection cases, both shroud and disc heat transfer are increased in mixed convection. Changes in disc heat transfer from the axial convection case are particularly strong. In all the conditions, laminar kinematic Ekman layers occur on the discs, but the disc thermal boundary layers for axial and mixed convection are considerably thicker.
•Open-source CFD code is applied to the pure centrifugal buoyant driven flow in a rotating disc cavity, with results comparing well to the published data. The calculations are then extended to axial convection and mixed convection with Rayleigh numbers up to 109.•Under axial convection and mixed convection, temperature gradient and mean flow circulation along the axial direction are developed. In the mixed convection, turbulence level in the cavity and heat transfer on the shroud are both increased.