5 Replies Latest reply on Dec 3, 2012 9:41 PM by Sak Vel

    flow simulation

    Sak Vel

      when i run flowsimulation by using externel option i cloud not get tempreature changes ,eventhough i enable the heat conduction in solid option?

        • Re: flow simulation
          Chris Michalski

          Sak -

           

          we're going to need a bit more detail to help you locate the problem.  Can you post a picture of the simulation?  Or better yet the model itself?

           

          It could be that your computational domain is too large and the solid is not accurately represented in the mesh.  Did you look at the mesh of solid cells?

          • Re: flow simulation
            Sak Vel

            Untitled.pnghi chris here i explain all ,the reason of this project is to get know  possiblities air recycling.

             

             

            situation

             

            the building length 22m width 13 m height 4 m appox with louverd wall in three sides and one side closed with no roof on top.

             

            we going to install 16 a/c condensing m/c with total of 23 fans in operation and 23 is standby simultaniously.(see photos)the air flow through the condensor coil (which is in red colour and coil is a porous media with 65 degree,ambiant temp 50 degree) and flow vertically to atmosephere(fan in blue colour)

             

             

             

            the question is ,while  all the 23 fans in operation

             

            how the pressure loss in the bulding?

             

            what will be the velosity of air access throughy louvared wall and porous media(coil)?

             

            if there is a huge pressure loss in the bulding, what will be the consqunce? (discharged air from the fan can recycle through the coil)

             

            we deeply conceren about one question which is how to know wether the air recycle or not?

             

             

            input

             

            external option

             

            heat conduction in soild ON

             

            gravity ON in y axis

             

            pressure potential ON

             

            ambiant temp 50 degree

             

            porous media 65 degree

             

            mesh - default(i mean -3)

             

            my computational domain 50 m in all axis

             

            i created and input fan curve and porous media pressure and flow rate (external outlet fan)

             

             

            i gave 23 fan input and 23 porous media input (i created engineering database with thermal conductivity,heat coefficiend)

             

             

            so, this is very intence resource

             

             

            i  hope u understand my requirement ,if not ask me

             

            what happend when i run this the system crashed couple of time and it did not give any heat transfer value

             

             

             

            please help me

              • Re: flow simulation
                Chris Michalski

                Sak -

                 

                looking at that picture you are likely going to have problems.  That is a large model to run a flow simulation on with small dimensions.  Did you look at the mesh before solving?  I would assume that with such a large model you will not accurately represent the geometry with an automatic mesh.  Even a manually defined mesh will likely be limited by RAM.

                 

                My 1st impression is that you should simplify the geometry for this to start.  After you mesh the model (without attempting to solve), look at the solid mesh and see if you can visualize your AC units.  My guess is that you will see a few scattered blocks but if you ask someone who is not involved they could not see the relation. 

                 

                My suggestion would be to make simple blocks for each unit that are as simple as possible - rectangular solids with cylinders on top for the fans, and a tapered cut in the side for the coil/air inlet.

                 

                You should also look into EFD Zooming.  This would let you solve the flow around each unit, 1 at a time, then it would simplify the overall simulation by maintaining those parameters constant and calculating how they influence each other. 

                 

                Unfortunately my newest Flow license is 2009 so I can't offer to actually look in your model to be more specific.  The best I can offer is: simplify.