6 Replies Latest reply on Jul 23, 2012 9:29 AM by Bill McEachern

    Fluid Analysis without inlet/outlet, using CFD

    Danny Pearson

      I work for a company that makes blenders, so there is no inlet and no outlet for our product/fluid.  It is just in a tank and get mixed.  We don't currently have Flow Simulation Premium.  I saw with that, you can do analysis with a rotating object (i.e. blending blade).  Can you run simulations without an inlet or outlet, or do all simulation tests require an inlet and an outlet?  If it requires them, I'm guessing this software would probably do nothing for us.  Thanks.

        • Re: Fluid Analysis without inlet/outlet, using CFD
          Chris Michalski

          Danny -


          what would you be trying to simulate?  the mixing of multiple liquids?


          SW Flow can't do interaction of liquids and gases if you want to simulate entraining air.


          I've got some downtime this afternoon so I'll setup something quick and easy and see if it complains.

            • Re: Fluid Analysis without inlet/outlet, using CFD
              Danny Pearson



              Thank you for your response.  I essentially have a tank like this one, it will have product in it, and the center shaft rotates, causing all those blades to mix the product.  The ends won't have holes and there will be a lid (everything isn't in the picture).  I just need to see the flow pattern of the product inside the tank.  Mixing of multiple liquids would be nice, but not completely necessary.  It would just be good to see how the product is going to move around in the tank.



            • Re: Fluid Analysis without inlet/outlet, using CFD
              Bill McEachern

              The limitations in flow are no free surface and it uses the rotating frame approximation for rotating objects. The rotating frame approximation is only supported in the steady state analysis option. The rotating frame  approxiamtion smears out the response azimuthally so details of the rotor stator interaction are not resolved. What is resolved is the overall flow characteristics. The lack of support for a free surface means that one has to totally enclose the flow volume. In this case it would mean putting a "lid" to replace the free surface. If the rotor pentrates the free surface the analysis maybe problematic. If it does not, ie the fluid volume submerges the rotor, thena  lid can be placed to replace the free surface and given a frcitionless or ideal wall condition. A small opening maybe required to get a solution to run which would have an ambient pressure BC and located on the free surface lid BC. The amount of inflow or out flow can be resovled at thes BC which should be small as in inconsequential. The flow pattern will then be resolved to a likely decent approximation of what is actually occuring and should provide insight into what you are seeking.