SourceSink Element Constant Coefficient Overdefined Inputs

[Anders Bjork (Thunderhead Engineering)]

Hello,

I'm experimenting with modeling gas mixtures that include non-trace Species.

When I enter both a Generation Rate (G) and a Removal Rate (D) the model behaves ... oddly. I am guessing that it acts like only a Source in the ContamX calculations.

Obviously, it does not make much sense to enter both values for any real world SourceSink model. But this came up when I was talking with another CONTAM learner, so I wanted to mention it for others to avoid too!

See attached PNG and PRJ Files.

Is there something I am missing in the math?

Thank you!

Anders

Thunderhead Engineering

[Dols, William Stuart (Fed)]

Anders,

I'm not sure what exactly it is you're trying to accomplish with this example.
However, it is easy to verify that setting the removal rate to zero results in different concentration time histories for both contaminants (hence the removal rate is in effect in your case).
It would be best to fully explore your findings before warning people to “avoid” features of the tool.
I would suggest that you perform an analytical analysis using a simple test case, e.g., single zone using trace contaminants, to verify CONTAM’s performance with respect to source/sinks.

The math involved is not that complex, but I sometimes utilize tools like Mathematica to generate such verification tests.

 

This is also a fairly unusual case in that the zone contains only a single flow path, you’re using non-trace contaminants, and adding mass to the zone as though from a compressed gas cylinder.
I will leave it at that, because I think this is such a fringe case that I don’t want to spend too much time getting into the weeds.

- Stuart

 

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[Anders Bjork (Thunderhead Engineering)]

Sounds good, thank you for the information.

You are right, I will try to understand the removal rate math better.

My apologies for implying that a feature wasn't working properly,

Anders