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-   -   Age of multiplephase flows fluids (http://www.cfd-online.com/Forums/cfx/23116-age-multiplephase-flows-fluids.html)

 Michael B September 29, 2006 04:03

Age of multiplephase flows fluids

Hi.

I'm doing a multiphase flow calculation involving gas and dispersed solid particles. I am a using a Euler-Euler approach. I have a geomtry with several inlets and the solid particles are injected in the most downstream of them. Only one outlet is there.

I would like to know the residence time for the particles compared to the fluid, so I have followed the guide from Robin from 2005:

I can easily come up with the residence time for the fluid, but the solid particles are harder to get.
I have set up two additional variables. Age and Age solids in order to compute the Age for each phase:

LIBRARY:
Option = Definition
Tensor Type = SCALAR
Units = [s]
Variable Type = Volumetric
END
END
LIBRARY:
Option = Definition
Tensor Type = SCALAR
Units = [s ]
Variable Type = Volumetric
END
END

I have then created two identical subdomains, where only the Age Solid and Age differs.

SUBDOMAIN: Subdomain 1
Coord Frame = Coord 0
Location = FLUID
BULK SOURCES:
Option = Use Volume Fraction
EQUATION SOURCE: Age
Option = Source
Source = 1 [m m^-1]
END
END
END
SUBDOMAIN: Subdomain meal
Coord Frame = Coord 0
Location = Assembly
BULK SOURCES:
Option = Use Volume Fraction
EQUATION SOURCE: Age solid
Option = Source
Source = 1 [m m^-1]
END
END
END
END

My problem is that the solid particles have age values between -10^24 and 10^24 and obviously are wrong. What I am doing wrong?