Learning Forum

[Kadhim]

Hi everyone,

I would really appreciate if anyone can help me with my issue.

I am using ansys cfx to create a planar jet flow, injecting methane a atmospheric air and then indicate the volume fraction of methane in the domain. when I create a structured mesh (Hexahedron one), I got the a constant value of volume fraction which is (one) (which is wrong results), however, when I change the mesh to be a Tetrahedron shape (with same B.C), i got good result but not symmetric as it should be. moreover, the velocity profile for both cases is the same and it is correct.

if anyone face kind of problem, please share your opinion with me. I attached the tow results as well in the pictures.  

 

[Rob]

Please add the images into your post: staff are not permitted to open attachments. 

[Kadhim]

I did, can you see them now?

[DrAmine]

More details about domain settings model and bc please.

[Kadhim]

i am using k-e model for now, the domain is like a cylinder with L=1.5 m and outer diameter D=0.4 m, initial conditions are V (volume fraction) = 0 for methane and = 1 for air. more details are in bellowing picture  

[DrAmine]

Why using multiphase approach for gases? You should model this by multicomponent gaseous mixture.

[Kadhim]

but I am using CFX and there is no such option

[DrAmine]

There is an option if you define a mixture material. Have a look in the standard tutorials.

[Kadhim]

and it is isothermal process, energy equation is off

[Kadhim]

Can you please send me any link coz I don't have an access to the tutorials 

[DrAmine]

Tutorials are on the Help Website. Wherever you are in CFX just hit "F1" and you get directed to the help (assume you are working with a newer ANSYS Release). I cannot share any tutorials on this community.

[DrAmine]

https://forum.ansys.com/forums/topic/how-to-access-the-ansys-online-help/

[Kadhim]

 trying to get the tutorials, but do you think  it is the reason of my problem?

[DrAmine]

Might be.