how to define a generic contaminant
 

Hi All,
i'm studying the diffusion problem in a ventilated room. I introduced a contaminant in my model and i used the tutorial (general - number 11) but i would like to know more about the density formula and the others properties of the material. Someone can give me some references?
I'm consider air in my domain and i would like to introduce a generic contaminant, but i don't understand how to define it. Thx for the attention,

Marco

Contaminant - density specification
 

If the contaminant enters in trace amounts then the mixture density can be taken as that of air, i.e. the contaminant is passive.

If the contaminant enters in appreciable amounts, then the mixture density will be a function of the local composition of air-contaminant mixture.

For the general case, the mixture density will be a function of both local composition and temperature, and also pressure if the flow is compressible.

In all these cases, the mixture density can be computed from the ideal gas law, with the mixture gas constant computed from summation of the gas constants for air and the various contaminants injected into the air stream. The gas constant for each gas component of the mixture is given by the universal_gas_constant*mass_fraction_of component/molecular_mass_of_component.

Thanks for the reply,


Marco