Numerical study of the conjugate mixed convection in inclined finned annulus

The current study presents a numerical simulation of three-dimensional heat transfer by mixed convection between two inclined concentric cylinders. The outer cylinder undergoes internal volumetric heating, while the inner one remains adiabatic. The annulus is equipped with eight internal longitudinal fins attached to the outer cylinder. In this work, the effect of the annulus inclination angle on the fluid dynamics and heat transfer performance is investigated. The convection in the fluid region is associated with heat conduction in the solid wall thickness. The conservation equations are solved using the finite volume method with a second-order space-time discretization. The studied inclination angles are: 0, 15, 30, 45, 60, 75, and 90?, the Prandtl number is 8.082, while the Reynolds and Grashof numbers are 399.02 and 12801, respectively. The results showed that the axial Nusselt number increases with the decrease of the inclination angle, the dynamic and thermal fields become axisymmetric in the vertical annulus case. Moreover, the used fins at the bottom azimuthal position improved the heat transfer better than those at the upper. Finally, a correlation which quantifies the rate of heat transfer is added.