Learning Forum

[ms101]

[Rob]

I'm not sure what set the Net Nanny off, but feel free to re-add the censored word with some spaces. If it's rude we'll clean up later. Don't worry it's overly sensitive to several engineering terms which, after some research, turned out to mean something else in slang!
Does the bellow act directly on the patient (ie assisted breathing) or indirectly (say via a diaphragm) on a separate fluid stream? The CFD solver Fluent is best suited for the flow, but if the bellows suffer significant self contact you may need LS Dyna which is more a Mechanical solver with some fluids functionality.

[ms101]

sorry that I used a wrong word unintentionally. The bellowwill be connected to the body through a check valve and when the bellow is compressed the bellow's coils touch each other. Can you refer me to related explantional videos to follow?

[Rob]

I'm not sure what we have on LS Dyna as it's not my field. If you can assume the rate of volume change is analogous to the pressure (suction) generated then Mechanical with contact may be sufficient. Basically the issue is the surface contact, as we can't do that in Fluent.

[ms101]

I definitely believe it is a mechanical issue as the negative pressure generated by the bellow depends on its material, wall thickness, and the diameter of its coils. SOif we want to model the bellow we can model it with a spring. For that reason, I want a program that can link the extension force of the bellow with the generated negative pressure.

[Rob]

In Mechanical we can find the rate of change of volume. Mapping that to CFD would then give you a pressure distribution, except we can't do the surface contact. LS Dyna can handle contact, but I don't know about their CFD solver.