Role of thermal disequilibrium on natural convection in porous media: Insights from pore-scale study

2017 ◽  
Vol 95 (3) ◽  
Author(s):  
Hamid Karani ◽  
Christian Huber
Keyword(s):  
Porous Media ◽  
Natural Convection ◽  
Pore Scale ◽  
Convection In Porous Media

scholarly journals A macroscopic two-length-scale model for natural convection in porous media driven by a species-concentration gradient

2021 ◽  
Vol 926 ◽  
Author(s):  
Stefan Gasow ◽  
Andrey V. Kuznetsov ◽  
Marc Avila ◽  
Yan Jin
Keyword(s):  
Porous Media ◽  
Natural Convection ◽  
Sherwood Number ◽  
Darcy Number ◽  
Scale Model ◽  
Length Scale ◽  
Pore Scale ◽  
Diffusion Term ◽  
Engineering Problems ◽  
Convection In Porous Media

The modelling of natural convection in porous media is receiving increased interest due to its significance in environmental and engineering problems. State-of-the-art simulations are based on the classic macroscopic Darcy–Oberbeck–Boussinesq (DOB) equations, which are widely accepted to capture the underlying physics of convection in porous media provided the Darcy number, $Da$ , is small. In this paper we analyse and extend the recent pore-resolved direct numerical simulations (DNS) of Gasow et al. (J. Fluid Mech, vol. 891, 2020, p. A25) and show that the macroscopic diffusion, which is neglected in DOB, is of the same order (with respect to $Da$ ) as the buoyancy force and the Darcy drag. Consequently, the macroscopic diffusion must be modelled even if the value of $Da$ is small. We propose a ‘two-length-scale diffusion’ model, in which the effect of the pore scale on the momentum transport is approximated with a macroscopic diffusion term. This term is determined by both the macroscopic length scale and the pore scale. It includes a transport coefficient that solely depends on the pore-scale geometry. Simulations of our model render a more accurate Sherwood number, root mean square (r.m.s.) of the mass concentration and r.m.s. of the velocity than simulations that employ the DOB equations. In particular, we find that the Sherwood number $Sh$ increases with decreasing porosity and with increasing Schmidt number $(Sc)$ . In addition, for high values of $Ra$ and high porosities, $Sh$ scales nonlinearly. These trends agree with the DNS, but are not captured in the DOB simulations.

scholarly journals Effects of pore scale on the macroscopic properties of natural convection in porous media

2020 ◽  
Vol 891 ◽  
Author(s):  
Stefan Gasow ◽  
Zhe Lin ◽  
Hao Chun Zhang ◽  
Andrey V. Kuznetsov ◽  
Marc Avila ◽  
...  
Keyword(s):  
Porous Media ◽  
Natural Convection ◽  
Pore Scale ◽  
Macroscopic Properties ◽  
Image Position ◽  
Convection In Porous Media

Natural Convection In Porous Media

10.2118/6813 ◽  
1968 ◽  
Author(s):  
K. Aziz ◽  
P.H. Holt ◽  
P.S. Karra
Keyword(s):  
Porous Media ◽  
Natural Convection ◽  
Convection In Porous Media
Sign in / Sign up

Export Citation Format

Share Document