Mixed Convection in a Rotating Concentric Annulus with a Porous Sleeve

2019 ◽  
Vol 33 (2) ◽  
pp. 483-494 ◽  
Author(s):  
J. C. Leong ◽  
F. C. Lai
Keyword(s):  
Mixed Convection ◽  
Concentric Annulus ◽  
Porous Sleeve

Mixed Convection in Rotating Concentric Annulus With a Porous Sleeve

2003 ◽  
Author(s):  
J. C. Leong ◽  
F. C. Lai
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Numerical Solutions ◽  
Outer Cylinder ◽  
Darcy Number ◽  
Thermal Buoyancy ◽  
Concentric Annulus ◽  
Concentric Cylinders ◽  
Inner Surface ◽  
Porous Sleeve

Numerical solutions are presented for mixed convection in rotating concentric cylinders with a porous sleeve. The porous sleeve is press-fitted to the inner surface of the outer cylinder. While the inner cylinder is rotating at a constant speed, the outer cylinder remains stationary. The main objective of the present study is to numerically investigate the flow pattern and temperature distribution as affected by the presence of the porous layer, the centrifugal force, and thermal buoyancy. A parametric study has been performed to investigate the effects of Peclet number, Rayleigh number, and Darcy number on the heat transfer results.

scholarly journals Large Eddy Simulation of liquid metal turbulent mixed convection in a vertical concentric annulus

2020 ◽  
Author(s):  
Luca Marocco ◽  
Francesco Garita
Keyword(s):  
Reynolds Number ◽  
Liquid Metal ◽  
Large Eddy Simulation ◽  
Mixed Convection ◽  
Forced Convection ◽  
Liquid Metals ◽  
Outer Radius ◽  
Concentric Annulus ◽  
Eddy Simulation ◽  
Large Eddy

In the present study turbulent forced and mixed convection heat transfer to a liquid metal flowing upwards in a concentric annulus is numerically investigated by means of Large Eddy Simulation (LES). The inner-to-outer radius ratio is 0.5. The Reynolds number based on bulk velocity and hydraulic diameter is 8900, while the Prandtl number is set to a value of 0.026. A uniform and equal heat flux is applied on both walls. LES has been chosen to provide sufficiently accurate results for validating Reynolds-Averaged turbulence models. Moreover, being the thermal sublayer thickness of liquid metals much larger than the viscous hydrodynamic one, liquid metals present a separation between the turbulent thermal and hydrodynamic scales. Thus, with the same grid resolution it is possible to perform a LES for the flow field and a “thermal“ Direct Numerical Simulation (DNS) for the temperature field. Comparison of the forced convection results with available DNS simulations shows satisfying agreement. Results for mixed convection are analyzed and the differences with respect to forced convection at the same Reynolds number are thoroughly discussed. Moreover, where possible, a comparison with air is made.

scholarly journals Large Eddy Simulation of Liquid Metal Turbulent Mixed Convection in a Vertical Concentric Annulus

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Luca Marocco ◽  
Francesco Garita
Keyword(s):  
Reynolds Number ◽  
Liquid Metal ◽  
Large Eddy Simulation ◽  
Mixed Convection ◽  
Forced Convection ◽  
Liquid Metals ◽  
Outer Radius ◽  
Concentric Annulus ◽  
Eddy Simulation ◽  
Large Eddy

In the present study, turbulent forced and mixed convection heat transfer to a liquid metal flowing upwards in a concentric annulus is numerically investigated by means of large eddy simulation (LES). The inner-to-outer radius ratio is 0.5. The Reynolds number based on bulk velocity and hydraulic diameter is 8900, while the Prandtl number is set to a value of 0.026. A uniform and equal heat flux is applied on both walls. LES has been chosen to provide sufficiently accurate results for validating Reynolds-averaged turbulence models. Moreover, with the thermal sublayer thickness of liquid metals being much larger than the viscous hydrodynamic one, liquid metals present a separation between the turbulent thermal and hydrodynamic scales. Thus, with the same grid resolution, it is possible to perform a LES for the flow field and a “thermal” direct numerical simulation (DNS) for the temperature field. Comparison of the forced convection results with available DNS simulations shows satisfying agreement. Results for mixed convection are analyzed and the differences with respect to forced convection at the same Reynolds number are thoroughly discussed. Moreover, where possible, a comparison with air is made.

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