8 Replies Latest reply on Oct 11, 2011 12:04 PM by dink dinkler

    Modeling Fluid Reservoir?

    dink dinkler

      So I have a "kinda" spherical but symmetric pressure vessel.


      Inside this pressure vessel there is water.


      I have a series of (lets call them) soda straws blowing air through the water.

      And then an exhaust a the top of the tank.


      I am trying capture what configuration of "soda straws" creates the lowest pressure drop. I am not looking to do multi-phase flow.


      My problem/question stems from the fact that for the life of me, I cannot figure out how to model the water level in this vessel as it has an air-gap at the top.


      I've tried using a cap and fluid subdomain and have tried putting a solid in that would be the water volume and disable that solid.

      Neither approach worked.





      Thanks in advance.

        • Re: Modeling Fluid Reservoir?
          Deepak Gupta

          Can you share a cut section and full view (pictures) of your current model and it'll be easy to suggest something.

          • Re: Modeling Fluid Reservoir?
            David Harrold

            I could be wrong, but it definitely sounds like you're modeling a bong. I will be interested to see this simulation.


            To set the water level, try making a cut feature or split surface at the waterline. Also, make sure gravity is applied in the correct direction.


            • Re: Modeling Fluid Reservoir?
              dink dinkler

              Unfortunately it is not something I can share any views of for reasons of confidentiality to our customer.

              But for simplicity's sake (and comedic value following that last post) lets just say it IS a bong. haha


              If it would help I can try to throw together something that doesnt divulge anything confidential... but it will just take some time.

              Please ask any clarifying questions and I will do my best to answer.


              I'll try and cobble something together to be representative of the problem.

              • Re: Modeling Fluid Reservoir?
                dink dinkler

                This should offer a good generic model of what I am trying to accomplish.


                The "soda straws" are completely submerged in the water which comes up about half-way up the vessel volume.

                The "snorkel" is the exhaust port.


                I am trying to get the pressure drop from the beginning of the straw to the end of the snorkel.


                  • Re: Modeling Fluid Reservoir?
                    Rich Bayless



                    Feel free to post your model.


                    I must be missing something here.  If you are interested in the overall pressure drop of the air, why even add the water to the model?  Just add the hydrostatic pressure to your air inlet pressure drops?


                    The multiple inlet pipes will each have a pressure drop.  The single outlet pipe will have a pressure drop.  The motion of the air bubbles through the water will be driven by bouyancy, hence no pressure drop.  Add up the inlet delta p, the outlet delta p, and the hydrostatic pressure, to get the overall delta p.


                    BTW, since you started a 'name the model' contest, my entry will be that it's a batch mode protein fractionator.



                  • Re: Modeling Fluid Reservoir?
                    dink dinkler

                    Anyone? Beuler?


                    I recently had a thought...

                    What if I modeled it as a porous media with very little actual material substance and made a pressure gradient in the vertical axis to mimic head loss?