I am modeling a heat exchanger with two different fluids : water and another one with different.

These two fluids do not mix up.

How can I specify operating density for each of these fluids ? They are totally different.

And if I don't specify operating density, what happens ? how fluent compute it ? Is it a different one for the 2 fluids ? Is there a way to see what the operating density computed by fluent is worth ?

Thanx for any help.

For multiphase flows it is better to specify Operating density as the density of the lowest of two fluids. If any of the fluid is compressible operating density should be set as zero. By default, Fluent will compute the operating density by averaging over all cells

-Sujith S Nair

but it is not a multiphase flow, it is 2 fluids separated by a wall...

[sso]

Dear fluent-users

I have the same problem; I have two different incompressible fluids in two pipes. These two streams don’t mix up.

Each of them has a density (has an operation pressure).

How I can specify that I have two different operating pressures or two different densities?

[hatef_khaledi]

Originally Posted by Sujith
;137994

For multiphase flows it is better to specify Operating density as the density of the lowest of two fluids. If any of the fluid is compressible operating density should be set as zero. By default, Fluent will compute the operating density by averaging over all cells

-Sujith S Nair

Could you explain why the reference density should be set to zero for compressible fluid?