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equation goal for concentration to stop calculation?

Question asked by Dan Hofstetter on Oct 24, 2013
Latest reply on Oct 24, 2013 by Jared Conway

I am working with a transient analysis that I would like to stop automatically when I reach a certain gas concentration in a tank.  The tank is a box with a circular inlet on the top at one end, and a rectangular outlet on the top at the other end.  The circular inlet is a simple Inlet Volume Flow, and the rectangular outlet is set to Environmental Pressure.  I have a volume goal for the tank airspace defined, and I have tried messing with equation goals to tell the solver when to finish the calculation.  Does anyone know of a slick way to make this happen?  Is it even possible?  I'm working with an initial gas concentration of 100 ppm, and I would like the solver to stop when that concentration drops below 10 ppm.  I tried the following:

 

1.  Set up equation goal = 11 - {VG Max Volume Fraction of Gas}

2.  Set calculation control options to use equation goal for convergence, then set criteria to 1 ppm

 

I am not sure this will do what I really want though, since the delta between iterations could be < 1 ppm even when the maximum concentration is > 10 ppm.  I'm basically trying to prevent the solver from running any longer than necessary.  Any ideas?

 

- Dan

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