writing UDF in AcuSolve

Junta_20361

Hello expert,

I'm working on a simulation where the material is a mixture of N2, Co2 & O2.

I use species transport function to define the gas mixture.

Now, the viscosity and density of this mixture will be calculated by UDF with below equation:

Gas_vis = VisO2 * specO2 + VisCo2 * specCo2 + VisN2 * (1 - specO2 - specCo2)

where VisO2, Co2, N2 are user input values; specO2 & specCo2 are species data at each elems, provide by acusolve udf.

To be honest, i don't have much experience in this domain and having trouble defining specO2 and specCo2.
Below is my definition of specO2 & specCo2:

When compiling, acusolve notified there are errors at line 50 & 51.
Could you help me check & modify it for me?

Attached is my full udf.

Thanks in advance!

acupro

Can we assume here that your are indicating num_species = 2 in the EQUATION command?

Can we also assume:

    If  species_1 = 0 and species_2 = 0; the properties should be that of N2
    If  species_1 = 1 and species_2 = 0; the properties should be that of O2
    If  species_1 = 0 and species_2 = 1; the properties should be that of Co2

Thank you.

Junta_20361

acupro_21778 said:

Can we assume here that your are indicating num_species = 2 in the EQUATION command?

Can we also assume:

    If  species_1 = 0 and species_2 = 0; the properties should be that of N2
    If  species_1 = 1 and species_2 = 0; the properties should be that of O2
    If  species_1 = 0 and species_2 = 1; the properties should be that of Co2

Thank you.

Hi acupro,

Thanks for your response.

1. I defined num-species = 2, which are CO2 and O2. I consider the N2 is the background.

2. "   If  species_1 = 0 and species_2 = 0; the properties should be that of N2
    If  species_1 = 1 and species_2 = 0; the properties should be that of O2
    If  species_1 = 0 and species_2 = 1; the properties should be that of Co2"

yes, it is the same as by expression.

acupro

Please try the attached udf.  Make sure you enable DERIVED_QUANTITY_OUTPUT at the same frequency as NODAL_OUTPUT so you can make sure the resultant viscosity is as you desire, based on the species results.

Junta_20361

acupro_21778 said:

Please try the attached udf.  Make sure you enable DERIVED_QUANTITY_OUTPUT at the same frequency as NODAL_OUTPUT so you can make sure the resultant viscosity is as you desire, based on the species results.

hi acupro,

Very nice!

Thanks for your great help!

Gamal2023

Hi Junta, 
Hi Acupro

I wan to simulate H2S dispersion in atmosphere. I am a new to CFD in general and Acusolve in particular. I would request your assistance to active species in Acusolve 2022.3, and defien gas mixture properties. Which physical model to implement in acusolve to study H2S dispersion and predict its concentration at certain points of interest.

I hope you can assist and guide me through out my project

acupro

Gamal2023 said:

Hi Junta, 
Hi Acupro

I wan to simulate H2S dispersion in atmosphere. I am a new to CFD in general and Acusolve in particular. I would request your assistance to active species in Acusolve 2022.3, and defien gas mixture properties. Which physical model to implement in acusolve to study H2S dispersion and predict its concentration at certain points of interest.

I hope you can assist and guide me through out my project

Posted a response on the other, similar conversation.