Multi scalar

[Anonymous]

Hi Dear Engineers -

I am working on a gas flow simulation project that involves three types of gas .

Air -Methane -Ethane 

Both of gas (Mixture - 90 % methane -10 Ethane ) Cross through Pipe And leakage to ambient of Building 

how  i can Define 2 Scalar gas  For Pipe inlet - my full mass rate 190000 Lb/Hr -inlet pressure 1024 psig

photo could help you better understanding modeling .

Thank you for help 

M.jamali 

[marwan_azzam]

Hello M.Jamali,

Photo is not much help, it is upside down.

In general, you can perform a CFD scalar analysis to simulate mixing of different fluids.  The material will have to be the same since CFD does not allow different fluids to touch each other.

The differing fluids at the inlets are modeled by making the properties, mainly the density and/or viscosity, a function of scalar.

Please refer to this section of the documentation.

Marwan

[Anonymous]

thank you for response but in the fact problem is here that i can not define 2 gas with Present  just  For one  inlet

also  i seen your Webinar about mixture and scalar but in that webinar scalar through from different inlet and did not use  1 inlet for two gas .

thank you  

[marwan_azzam]

I see.

How does that physically happen that they both come in at the same inlet?

Your model would have to include what's upstream of that inlet where the two fluids are separate.

Marwan

[Anonymous]

Thank You - this model is for analysis Station gas Pipe Line and  We Consider Fluid in pipe Involve 2 huge part of real mixture (Methane and Ethane ) -

may be Guide me,how Separate The Inlet Mixture - can i define 2 mass rate that calculated according to gas densities or  Not if  i do  it . it is necessary to define pressure inlet or not 

i send other photo more clear info-

i am thankful for your helps .

[marwan_azzam]

I would set the outlet and crack in pipe to P = 0 and remove the pressure BC on inlet.

As for modeling upstream, you can have two separate inlet pipes for the two fluids that meet (like a Y).  Each will have it's own flow rate.  One will have to be scalar=0 to represent one fluid and the other scalar 1 to represent the other.  There will be one material where the denesity and/or viscosity will be a function of scalar from 0 to 1.

Marwan

[Anonymous]

Thank you very much for Your help.