
[Sponsors] 
Modelling Density driven convection between CO2 and Water/saltwater/brine 

LinkBack  Thread Tools  Search this Thread  Display Modes 
December 20, 2014, 08:43 
Modelling Density driven convection between CO2 and Water/saltwater/brine

#1 
New Member
Join Date: Dec 2014
Posts: 2
Rep Power: 0 
Hi,
Trying to model the convection caused by the density difference between water and water that has been dissolved with carbon dioxide. This occurs in carbon capture storage systems. The carbon dioxide is injected into deep saline aquifers which are areas of porous rock surrounded by impermeable rock. the porous medium is saturated in water. The injected co2 begins to dissolve in the water creating a solution with a higher density than the surrounding water. This of course causes density/buoyancy driven convection. Does anyone know how to go about modelling this? the only things i can find about modelling natural convection which is primarily driven by heat transfer. Any help would be really appreciated. Thanks Last edited by CRAGIO; December 20, 2014 at 08:45. Reason: add tags 

December 31, 2014, 05:23 

#2 
Senior Member
Jamal Foroozesh
Join Date: Oct 2012
Location: Iran
Posts: 162
Rep Power: 13 
Hi dear friend
do you solve this problem? I have same problem. can you help me? 

January 1, 2015, 08:38 

#3  
Senior Member
Real Name :)
Join Date: Jan 2010
Location: United States
Posts: 192
Rep Power: 16 
Quote:
As far as modelling this, I suspect it will be a simple single phase, multicomponent model. That's not the hard part, however. There are two issues I see: 1) Fluid properties 2) Boundary conditions I suppose I'd first get your fluid properties correct first. CO2 can be a tricky one. Is this liquid CO2, dense phase, etc? What's the size of your domain? Will pressure change significantly due to elevation? Does the geothermal gradient come into play such that you have to worry about temperature too? Is the water entering the CO2 saturated with salt, or is it undersaturated such that you won't have to worry about it? The boundary conditions on your problem depend on how concerned you are about the draw down of water from the surrounding rock, or, rather, how constantly the porous media stays filled with water. This sounds like it's a wall boundary condition on all sides (except the inlet perhaps, which is a pressure boundary with CO2 mass fraction=1). The temperature, depending on the size of the domain, is either isothermal or perhaps T(z) due to the geothermal gradient. Perhaps you want to worry about locally cooling the rock, but at some point in your numerical domain (10m away from the CO2/Rock interface, perhaps), you're going to assume isothermal/T(z). To implement temperature as a function of depth is a simple UDF. Search the site or ask for help specifically on this. The inlet water flow is the toughest part. There are a number of ways you could do this. Keeping with the wall boundary conditions, I suppose what I'd do is simply loop around all the cells at the walls and adjust their mass fraction of water based on some known diffusion rate you have every step. If I recall, water/liquid CO2 diffusion is quite high (D ~ 2 × 10−7 m2/s). Assuming your fluid properties are robust, as well as your CO2<>H2O diffusion value, fluent will handle the rest. I'd start with the simplest case, see if it's giving you what you want, then come back once you've solved everything and want to move to something more complex. Let us know  good luck! ComputerGuy 

January 5, 2015, 15:19 

#4  
New Member
Join Date: Dec 2014
Posts: 2
Rep Power: 0 
Quote:


November 22, 2022, 01:44 

#5 
New Member
Md Fahim Shahriar
Join Date: Nov 2022
Posts: 9
Rep Power: 3 
Hello, did you figure this problem out? I want to simulate this exact thing but can't seem to do it after trying out a lot.
I use Multiphase VOF model, use CO2 as inlet (set is at mass flow inlet). But I can't get the finger pattern it makes when dissolving. Please help me out, if you get the chance. 

Tags 
dissolution, fluent, natural convection, two fluids 
Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Simulation of RayleighBenard convection  n0name  Main CFD Forum  2  April 27, 2014 13:49 
Convection in a liquid: density change in a closed volume  MrDaimon  FLUENT  0  February 14, 2014 06:56 
TwoPhase Buoyant Flow Issue  Miguel Baritto  CFX  4  August 31, 2006 12:02 
operating density in buoyancy driven flow  MarieAnne  Main CFD Forum  2  March 24, 2006 09:52 
variable density water  Atit Koonsrisuk  CFX  2  July 24, 2003 03:07 