species transport

cmageski · February 6, 2012, 13:04

Hello
I need simulated a species transport. Oxygen in water, with mass fraction and diffusion coefficient, but i don't know how to do.

ghorrocks · February 6, 2012, 19:01

Have you done the tutorials on additional variables, multicomponent and multiphase flows?

cmageski · February 7, 2012, 08:04

Yes, for multicomponent. But when I put the mass fraction of oxygen as multicomponent, the oxygen disappear in my geometry from one position. My geometry is followed by a contraction and expansion after expansion there is no oxygen in the fluid. I wonder if the CFX imposes zero mass fraction at the exit.
For additional variable, i din't understand very well the what is and din't found what tutorial . Send the name of tutorial this part talk about this exactly.

ghorrocks · February 7, 2012, 16:16

Can you describe what you are modelling? What is the oxygen doing in the water?

cmageski · February 8, 2012, 07:23

yes of course. I transporting oxygen through the water to find the concentration close to the wall and to estimate the corrosion according to the concentration of oxygen near the wall. but when using multicomponent transport oxygen after expansion tends to zero, oxygen is not the entire flow. The water have a saturation of the oxygen em mg/L free in water, and the oxygen a coefficient diffusion in water.

cmageski · February 8, 2012, 07:24

yes of course. I transporting oxygen through the water to find the concentration close to the wall and to estimate the corrosion according to the concentration of oxygen near the wall. but when using multicomponent transport oxygen after expansion tends to zero, oxygen is not the entire flow.

ghorrocks · February 8, 2012, 16:44

I would consider using an additional variable rather than a multi component mixture. Multi component mixtures are designed for multi-component gases, not gases dissolved in liquids.

cmageski · February 9, 2012, 11:12

Ok thank you. I will test.

cfdplayer · February 15, 2012, 05:08

Hi all,
I want to find the concentration distribution of a species in a region. The model has two zones. The distribution is being calculated in single zone only. How to include the permeability of the wall in between so that we can find the species distribution in the other zone also.

Thanks for your help.

ghorrocks · February 15, 2012, 05:27

Make the porous wall an interface and put a resistance coefficient on it.

monkey1 · February 15, 2012, 05:27

Hi cfdplayer!
If I got you right then you have 2 (connected) domains for your problem and you want the flow to go from one to the other?
If this is your problem you must use / set up the domain interface. Chapter 13 in the cfx_pre.pdf help files of CFX.

paoching · June 15, 2018, 17:33

I'm also simulating aqueous galvanic corrosion in fluent and are wondering if the stock gas mixture material is a suitable approximation of ionic species in water. Additional variables sounds like a promising solution to tracking ionic movement. How do I add the additional variables? is there a tutorial on that? I did a quick search on ANSYS help but it seems all the tutorial on additional variables is for CFX and not fluent.

ghorrocks · June 16, 2018, 05:03

Try the fluent forum.

February 6, 2012, 13:04	species transport	#1
cmageski New Member Cecília Mageski Join Date: Sep 2011 Posts: 16 Rep Power: 14	Hello I need simulated a species transport. Oxygen in water, with mass fraction and diffusion coefficient, but i don't know how to do.

February 6, 2012, 19:01		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,719 Rep Power: 143	Have you done the tutorials on additional variables, multicomponent and multiphase flows? cmageski likes this.

February 15, 2012, 05:08	wall permeability in species transport	#9
cfdplayer New Member anonymous Join Date: Jan 2011 Posts: 1 Rep Power: 0	Hi all, I want to find the concentration distribution of a species in a region. The model has two zones. The distribution is being calculated in single zone only. How to include the permeability of the wall in between so that we can find the species distribution in the other zone also. Thanks for your help.

June 16, 2018, 05:03		#13
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,719 Rep Power: 143	Try the fluent forum. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Modelling Biomass Combustion via Species Transport	Racheal	FLUENT	39	January 8, 2022 07:42
Please help!! Patch and Species transport	Julie	FLUENT	5	August 3, 2016 03:10
questions about species transport through walls	shuqin	FLUENT	13	April 9, 2014 02:42
Questions for a species transport problems (snapshots attached)	aleisia	FLUENT	2	October 9, 2011 04:40
species transport in water	lyn	FLUENT	1	December 12, 2007 18:15

February 7, 2012, 08:04		#3
cmageski New Member Cecília Mageski Join Date: Sep 2011 Posts: 16 Rep Power: 14	Yes, for multicomponent. But when I put the mass fraction of oxygen as multicomponent, the oxygen disappear in my geometry from one position. My geometry is followed by a contraction and expansion after expansion there is no oxygen in the fluid. I wonder if the CFX imposes zero mass fraction at the exit. For additional variable, i din't understand very well the what is and din't found what tutorial . Send the name of tutorial this part talk about this exactly.

February 7, 2012, 16:16		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,719 Rep Power: 143	Can you describe what you are modelling? What is the oxygen doing in the water?

February 8, 2012, 07:23		#5
cmageski New Member Cecília Mageski Join Date: Sep 2011 Posts: 16 Rep Power: 14	yes of course. I transporting oxygen through the water to find the concentration close to the wall and to estimate the corrosion according to the concentration of oxygen near the wall. but when using multicomponent transport oxygen after expansion tends to zero, oxygen is not the entire flow. The water have a saturation of the oxygen em mg/L free in water, and the oxygen a coefficient diffusion in water.

February 8, 2012, 07:24		#6
cmageski New Member Cecília Mageski Join Date: Sep 2011 Posts: 16 Rep Power: 14	yes of course. I transporting oxygen through the water to find the concentration close to the wall and to estimate the corrosion according to the concentration of oxygen near the wall. but when using multicomponent transport oxygen after expansion tends to zero, oxygen is not the entire flow.

February 8, 2012, 16:44		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,719 Rep Power: 143	I would consider using an additional variable rather than a multi component mixture. Multi component mixtures are designed for multi-component gases, not gases dissolved in liquids.

February 9, 2012, 11:12		#8
cmageski New Member Cecília Mageski Join Date: Sep 2011 Posts: 16 Rep Power: 14	Ok thank you. I will test.

February 15, 2012, 05:27		#10
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,719 Rep Power: 143	Make the porous wall an interface and put a resistance coefficient on it.

February 15, 2012, 05:27		#11
monkey1 Senior Member Join Date: Jul 2011 Location: Berlin, Germany Posts: 173 Rep Power: 14	Hi cfdplayer! If I got you right then you have 2 (connected) domains for your problem and you want the flow to go from one to the other? If this is your problem you must use / set up the domain interface. Chapter 13 in the cfx_pre.pdf help files of CFX.

June 15, 2018, 17:33		#12
paoching New Member Paul Lee Join Date: Jun 2018 Location: Vancouver Posts: 14 Rep Power: 7	I'm also simulating aqueous galvanic corrosion in fluent and are wondering if the stock gas mixture material is a suitable approximation of ionic species in water. Additional variables sounds like a promising solution to tracking ionic movement. How do I add the additional variables? is there a tutorial on that? I did a quick search on ANSYS help but it seems all the tutorial on additional variables is for CFX and not fluent.