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bilteryst March 19, 2010 02:55

Motion Wall with Floworks

My problem is quite simple. I'm trying to simulate with CosmosFloWorks an incompressible flow inside a syringe. So the flow just results from the motion of the piston. I just told it seems to be simple and yet, I tried different models without achieving pertinent results. The boundary conditions are a wall motion condition (for the piston) and an outlet static pressure condition.

May I ask some help to achieve a correct CFD model ? Thanks in advance.

Kiat110616 April 5, 2011 13:19

Can you post the picture and show the boundary condition was applied in your model?

bilteryst April 6, 2011 16:54

We did not continue with this study. But I try the following solutions :
- internal flow, translation speed for the piston, static pressure for the outlet, fixed walls elsewhere (I tried without this last condition too)
- external, but this one is outlandish since we can not use a mix of liquid and gas

We did not succeed in getting results with both previous solutions. So help would be still appreciated

Boris_M May 22, 2011 08:07

Hello bilteryst,
it is not possible to simulate moving pistons in FloWorks or Flow Simulation as it is called now. The question is, is it really necessary?
What do you want to find out?
I understand you want to simulate a syringe but if it is just about the flow how it gets into the needle, hence the relatively hard diameter jump then I would say you don't really need a moving piston. You have a diameter of the piston and if you define the pistons motion speed then the diameter*piston speed = volume flow for the inlet.


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