3 Replies Latest reply on Sep 3, 2010 12:00 AM by David Paulson

    Equivalent selection of Porous media for Flow through mesh and perf.

    Phani Kottapalli
      • I am trying to find equivalent resistance for Perf and mesh used in the Strainer. Creating a complete model is create huge memory and time consuming and problem for big size strainers
      • Solid works flow simulation has a Porous Media option, but I don’t  know how to choose equivalent porous media option for my application.
      • Please advise if there is any alternate equivalent flow resistance option in solid works flow for my application.
      • Porous media application in Solid works
        • How to define which type of porous media to be selected for Equivalent of perf and mesh geometry
        • While specifying the direction to porous media, which to be considered Porous geometry opening direction or fluid reference flow direction.
      • see attached picture of screens with only perf , but for fine filtration it will be covered with second layer of mesh matetrial. these screens are encloused in strainer body.
      • Perf details, hole opening-0.125 in , center distance between holes is 0.1875 in , open area percentage of Perd is 40%
      • Mesh opening is 0.0055 in, Open area percentage is 36%

       

      please advise any solution  to my application, if needed any  more information please let me know.

       

      Phani

        • Re: Equivalent selection of Porous media for Flow through mesh and perf.
          Bill McEachern

          I have a 4 x 4 array of the geometry, put it in a "wind tunnel" in flow with ideal walls and run a bunch of points over the velocity range of interest. Take the data and plot a flow rate vs pressure drop curve for the geometry. You then put in the small sample geometry (where it asks for it) into flow as a pressure drop vs flow rate and then it will scale for whatever the actual geometry in the model is. For your app a tip would be to make the conical section thicker to conserve the mesh as it has such angles which will drive mesh count. Then adjust the medium thickness to the same value. If the pressure drop is expected to be high you will need more than a couple cells across the medium to capture high pressure drops. For fabric type mediums or sintered types your only option is data from manufacturer or do a real test. this works pretty well in my experience.

          • Re: Equivalent selection of Porous media for Flow through mesh and perf.
            David Paulson

            Phani,

             

            Poruos media will not give you a good representation of your  issue.  From your model. the pressure drop will be very small.  You could model this with a screen instead of a perforated body with very close results.  You might have to modify the screen in the material data base for flow to be user defined to more closely model your perforations.  In reality, the pressure drop through a strainer such as you designed is relatively insignificant comapred to the pressure drop when it is loaded with material.

             

            I have used perforated plate on gas flows prior to entrance into a fabric mesh (porous media) on gas liquid separators.  The perforated plate did not seem to create a computational botleneck, although it was only a 12 diameter domed  plate.  I would recommend that you just run the simulation on the perforated material that you have designed.  The results you get in Flow will be more accurate than if you try to simulate your perforated pattern with a porous media, which it really is not.