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:
http://www.cfd-online.com/Forum/cfx_...cgi/read/11571

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:
ADDITIONAL VARIABLE: Age
Option = Definition
Tensor Type = SCALAR
Units = [s]
Variable Type = Volumetric
END
END
LIBRARY:
ADDITIONAL VARIABLE: Age solid
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?

Please help