I have been having some trouble with internal fans recently. I have a model where the initial concentrations are defined by a F(z) table:
|Z||H2S ppm||Z||Air ppm|
The internal fan is placed at the horizontal boundary between these two concentration levels, the inlet is on the air side, and the outlet is on the H2S side. I have not built the flow simulation configuration from scratch too many times, so I'm not sure of the correct order, but it seems that if I define the internal fan first, and then the F(z) initial conditions, everything plays nicely and the simulation works. If I defined the initial conditions first, then each time I set up a new internal fan, Flow Sim seems to grab the initial concentration data and use it for the fan output. So when I run the simulation, the fan essentially blows 156.9 ppm H2S into the tank constantly. I have not found a good way to fix this other than clearing the Flow Sim configuration and rebuilding the config from scratch.
Has anyone else noticed this? I'd call it a bug, but maybe this is common. I am using SW 2011 SP5.0.