CFX Oil - water flow in pore scale domain

iloc86 · December 14, 2016, 23:42

Hi guys, in few words, is it possible to simulate with CFX the flow of water in an initial oil filled "pore" (micro scale) and obtain some results such as how much oil remains in the pore because wettability of oil?, i have done some approaches but it failed in keep some vol frac of oil, it is sweeped by the water that enter to the domain. Any ideas, advices of how to do this.

ghorrocks · December 15, 2016, 04:06

In a few words: Yes, it is possible. But it might not be the model you are thinking of.

If you intend to model the 3D structure of the porous material and put some oil and water in it and see how much oil is left stuck in the material - yes, this is possible but you are likely to be modelling a very small section of the structure and it is likely to be a very large simulation. Look in the literature - there are many simulations of this type of flow. Is this what you had in mind?

iloc86 · December 15, 2016, 09:16

Thanks for the answer , Yeah u are right , im doing small domains aproaches for example a star shaped tube , in the corners is waited to maintain some oil ( as experiment does) and water keep flowing in the center of the star shape tube , im using small meshes to see what's happening in the corner and small time steps 1e7 s average but until now I can't see this acumulation in corners , water sweeps every thing , im using free surface model wall adhesion but im not so experienced in this field. First I just want to do a basic model that at least have this acumulation of oil by wttability, I have seen some examples of this cfd modelling for example capillary. If I have to do a basis aproach what can I have to do ? I'm thinking that the problem could be the contact angle of the fluids with wall's #!

ghorrocks · December 15, 2016, 17:55

I have done a lot of modelling of free surfaces and surface tension. It is a tricky area and the default setting of CFX are often not optimal.

Before doing your complex model I strongly recommend you do some simple benchmark cases and check you can accurately model simple cases first. Examples of good benchmark simulations include:

* Laplacian pressure in a spherical drop due to surface tension
* Capilliary flow in a fine tube
* Flow of a droplet into a corner by surface tension

All these cases have analytical answers so you can see exactly how accurate your model is. You will find the default CFX settings are not optimal and it runs better and more accurately with modifications. When you can model cases like these accurately you are ready to model your complex case.

December 14, 2016, 23:42	CFX Oil - water flow in pore scale domain	#1
iloc86 New Member ivan Join Date: Dec 2014 Posts: 14 Rep Power: 11	Hi guys, in few words, is it possible to simulate with CFX the flow of water in an initial oil filled "pore" (micro scale) and obtain some results such as how much oil remains in the pore because wettability of oil?, i have done some approaches but it failed in keep some vol frac of oil, it is sweeped by the water that enter to the domain. Any ideas, advices of how to do this.

December 15, 2016, 09:16	Thanks for the answer	#3
iloc86 New Member ivan Join Date: Dec 2014 Posts: 14 Rep Power: 11	Thanks for the answer , Yeah u are right , im doing small domains aproaches for example a star shaped tube , in the corners is waited to maintain some oil ( as experiment does) and water keep flowing in the center of the star shape tube , im using small meshes to see what's happening in the corner and small time steps 1e7 s average but until now I can't see this acumulation in corners , water sweeps every thing , im using free surface model wall adhesion but im not so experienced in this field. First I just want to do a basic model that at least have this acumulation of oil by wttability, I have seen some examples of this cfd modelling for example capillary. If I have to do a basis aproach what can I have to do ? I'm thinking that the problem could be the contact angle of the fluids with wall's #!

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December 15, 2016, 04:06		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	In a few words: Yes, it is possible. But it might not be the model you are thinking of. If you intend to model the 3D structure of the porous material and put some oil and water in it and see how much oil is left stuck in the material - yes, this is possible but you are likely to be modelling a very small section of the structure and it is likely to be a very large simulation. Look in the literature - there are many simulations of this type of flow. Is this what you had in mind?

December 15, 2016, 17:55		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	I have done a lot of modelling of free surfaces and surface tension. It is a tricky area and the default setting of CFX are often not optimal. Before doing your complex model I strongly recommend you do some simple benchmark cases and check you can accurately model simple cases first. Examples of good benchmark simulations include: * Laplacian pressure in a spherical drop due to surface tension * Capilliary flow in a fine tube * Flow of a droplet into a corner by surface tension All these cases have analytical answers so you can see exactly how accurate your model is. You will find the default CFX settings are not optimal and it runs better and more accurately with modifications. When you can model cases like these accurately you are ready to model your complex case.