Initializing a Pressure Vessel
 

Looking to evaluate the standard problem of a closed pressure vessel bleeding out through a series of pipes. I have assembled my pipe section with orifice and run the problem with an inlet having a constant velocity and then reran the model with a constant pressure inlet. I now want to attached the pipe section to a defined volume with a specified initial pressure and evaluate the flow through the pipes as the pressure vessel bleeds down. My problem is how to define an initial pressure level within the vessel alone. I am thinking that the solution has something to do with making an initialization run which somehow only brings the pressure vessel volume up to the pressure level I want, but I have yet to find a Fluent example which addresses this problem. Seems strange since a pressure vessel bleeding down is one of the basic problems one would find in any fluid dynamics course. Any suggestions on how to initialize the pressure vessel volume?

If you have your pressure vessel setup as it's own zone (have separate cell zones for the vessel and pipe), then you can patch the pressure in that zone.

In the worst case you can brute force it by writing an interpolation file, editing the pressure field manually (e.g. in matlab), and then reading the interpolation file.

I have been looking at the zone approach. I usually bring my models in as iges files from ProE so I need to figure out how to get the pressure vessel to be its own zone.