how to define diffusion coefficients for every species in the system?

Weiqiang Liu · June 15, 2019, 10:45

Hi all,

I wrote an UDF to define mass diffusion coefficients for all species in the system. For some reason, I need to hook my UDF in mixture material panel instead of single specie panel.

My UDF can be compiled and loaded without error. I also checked the returned value of mass diffusion coefficient which is 4.6e^-5. However it is only for one specie. In specific, specie index "i" is always 0 in DEFINE_DIFFUSIVITY(c,t,i) macro.

I wonder how can I define mass diffusion coefficients for every species in the system if I have to hook my UDF in mixture material panel?

Best.

Weiqiang.

Weiqiang Liu · June 16, 2019, 16:05

it turns out fluent can loop all the species in the system even if I hook my UDF in mixture panel.
Though it returns wrong value which I can not understand.

best

Weiqiang

qkhanh189 · September 26, 2019, 22:37

Quote:

Originally Posted by Weiqiang Liu

it turns out fluent can loop all the species in the system even if I hook my UDF in mixture panel.
Though it returns wrong value which I can not understand.

best

Weiqiang

Have you solved this problem yet?

Weiqiang Liu · September 28, 2019, 09:41

Quote:

Originally Posted by qkhanh189

Have you solved this problem yet?

I think yes. You just need to hook your UDF in mixture panel and fluent will loop all species in the system automatically.

Best

ppdhekne · November 26, 2019, 05:55

How to define mass transfer source term (mass diffusivity) in porous media? Which model should i use for mass diffusion through porous media? Thanks in anticipation

qkhanh189 · November 26, 2019, 09:43

Quote:

Originally Posted by Weiqiang Liu

I think yes. You just need to hook your UDF in mixture panel and fluent will loop all species in the system automatically.

Best

Could you help me with my problem here: UDF code for water absorption in Polymer

azores · June 23, 2021, 10:01

Hello Weiqiang Liu,

I have a similar problem. Could you provide your UDF to calculate diffusion coefficients for each species?

Thanks in advance!

Best regards,
Beatriz

azores · June 23, 2021, 10:03

Quote:

Originally Posted by Weiqiang Liu

I think yes. You just need to hook your UDF in mixture panel and fluent will loop all species in the system automatically.

Best

Hello Weiqiang Liu,

I have a similar problem. Could you provide your UDF to calculate diffusion coefficients for each species?
Thanks in advance!

Best regards,
Beatriz

June 15, 2019, 10:45	how to define diffusion coefficients for every species in the system?	#1
Weiqiang Liu Senior Member Weiqiang Liu Join Date: Feb 2018 Posts: 278 Rep Power: 9	Hi all, I wrote an UDF to define mass diffusion coefficients for all species in the system. For some reason, I need to hook my UDF in mixture material panel instead of single specie panel. My UDF can be compiled and loaded without error. I also checked the returned value of mass diffusion coefficient which is 4.6e^-5. However it is only for one specie. In specific, specie index "i" is always 0 in DEFINE_DIFFUSIVITY(c,t,i) macro. I wonder how can I define mass diffusion coefficients for every species in the system if I have to hook my UDF in mixture material panel? Best. Weiqiang.

November 26, 2019, 05:55	Mass transfer source term in porous media	#5
ppdhekne New Member Pallavee Dhekne Join Date: Aug 2019 Posts: 5 Rep Power: 6	How to define mass transfer source term (mass diffusivity) in porous media? Which model should i use for mass diffusion through porous media? Thanks in anticipation

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June 16, 2019, 16:05		#2
Weiqiang Liu Senior Member Weiqiang Liu Join Date: Feb 2018 Posts: 278 Rep Power: 9	it turns out fluent can loop all the species in the system even if I hook my UDF in mixture panel. Though it returns wrong value which I can not understand. best Weiqiang

June 23, 2021, 10:01		#7
azores New Member Beatriz Join Date: Jun 2021 Posts: 11 Rep Power: 4	Hello Weiqiang Liu, I have a similar problem. Could you provide your UDF to calculate diffusion coefficients for each species? Thanks in advance! Best regards, Beatriz