Learning Forum

[phil.hegedus]

If I have a box with air entering through an inlet, air exiting through an outlet, but the box lid isn't perfectly sealed, can Discovery Live handle the concept of leakage?

I've been able to treat the top opening of the box (where the lid would sit) as a secondary outlet but in doing so, it completely ignores the lid, which is modeled as a separate body from the box, no matter where I position it. Discovery Live doesn't show any particles exiting the box, either, since it seems to be treating the problem strictly as an internal flow one.

I'd like to have Discovery Live show the leakage and figure out the approximate pressure and flow rate through the gap between the lid and the box, especially as I move the lid around. Is this is too complex of a problem of Discovery Live?

[Brian Bueno]

TS

Discovery Live cannot handle mixed internal/external flow at the current point in time.

[phil.hegedus]

Thank you for the fast response!

[Andrew Stankovich]

TS Please look at this model and see if this is similar to what you are trying to do.

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[phil.hegedus]

Andrew Stankovich 

If I understand your example correctly, you've modeled two bodies - the first being the fluid volume and the second being a lid. Two outlet planes are defined by giving them a pressure of zero; the lid is meant to slide across the top plane to restrict or allow flow. Correct?

If so, this is essentially what I'm doing (I've drawn the box surrounding the fluid volume, as well) but I'd like Discovery Live to compute the average flow rate and pressure where the leakage occurs, as opposed to preemptively setting the pressure as a boundary condition. When the lid is closed, in the real life application, there is a positive pressure causing hot gases to vent out of the box. Only when the lid is substantially opened would I expect the pressure across the opening plane to drop to zero. I believe this effect turns the problem into a true mixed internal-external flow problem.

I'm going to try modeling a larger surrounding box to provide an equivalent atmosphere for the hot gases to leak into, possibly tricking the program into believing it's still an internal flow problem.