9 Replies Latest reply on Jun 5, 2014 6:53 PM by Jared Conway

    Defining Radiation on Solids!

    Nuno Moita

      Hello to all,

       

      I am glad to become a part of this community, did not know about this, that certanly helps a lot of people. I am registed as a non-sw users but in the company I do work we do have solidworks.

       

      Well, I have several doubts when using radiation in solidworks flow simulation that the help did not clearly clarify to myself (perhaps to not be native).

       

      - When in the wizard we choose the solid material, it is assume that all the solid will be with considered as the pickup one. eg. Aluminium.

      - After, when we then are obey to choose the radiation wall, all the surfaces will be with the pickup surface. So, we should choose to match the aluminium: Aluminium.

      (if this is not right, please correct me!)

       

      My question is: If, when defining another material in another solid in the assemly, for example rubber, what will happen to the surface? It will be cleaned or it will be kept as aluminium? I assume it will be clean and then I should select all the faces and select rubber for radiation?

      (It is something that is concerning me when using radiation).

       

      Best regards,

       

      Nuno

        • Re: Defining Radiation on Solids!
          Jared Conway

          default radiative surface applies to all surfaces

          over ride with radiative surfaces in the setup of the problem

          the material you choose does not automatically link to radiation properties, they are defined at the face level

          this is covered int the tutorials and the training

            • Re: Defining Radiation on Solids!
              Nuno Moita

              Hi Jared,

               

              Thank you again for your quick help.

               

              So, if in general settings I did have set aluminium for all solids and for the wall surface radiation, aluminium too, and if I set a new solid material afterwards, for example rubber, it will clean the surface radiation for this solid? Or it will be rubber with aluminium radiation surface? Because I did not set any radiation surface?

               

              Best regards,

               

              Nuno

                • Re: Defining Radiation on Solids!
                  Jared Conway

                  all of flow simulation is based on the concept of default that applies to all faces/bodies

                  and then overrides in the tree

                   

                  so if you chose aluminum

                  EVERY part is aluminum until you over ride the material

                   

                  material and radiative properties are set separately (consider that we're talking about coating, not just materials)

                   

                  so when you choose aluminum for the radiative wall

                  EVERY face is aluminum until you over ride the radiative surface properties

                    • Re: Defining Radiation on Solids!
                      Nuno Moita

                      Ok. So, when analysing the 150W halogen light  tutorial when it is set glass gasket as a solid it will keep the aluminium surface as they do not set any surface in this gasket. So, they should define for the surface of that gasket rubber, for eg. That was my doubt. Thank you.

                       

                      Best regards,

                       

                      Nuno

                        • Re: Defining Radiation on Solids!
                          Jared Conway

                          the default applies to all faces

                          then you override based on changes to the faces

                          the general recommendation is to start with everything as black body and adjust from there

                          look through the kb and the documentation and training

                            • Re: Defining Radiation on Solids!
                              Nuno Moita

                              Hi Jared,

                               

                              Thank you very much for your support.

                               

                              I have understand what you mean and it was quite clear. But when analysing the tutorial, the 150W halogen lamp is just an example, they do not override with a new radiation surface on the gasket, just simply set a new solid material, not the radiation faces. So, that can be assumed to be wrong as solidworks flow simulation will keep to use radiation on the gasket using aluminium (Although they will use condution as correct solid proprieties).

                               

                              Best regards,

                               

                              Nuno

                                • Re: Defining Radiation on Solids!
                                  Jared Conway

                                  Does the gasket see radiation? If not, it doesn't matter because it isn't a radiative surface

                                  Second, the only thing radiation surface does is change the emissivity, is it that much different from the default?

                                    • Re: Defining Radiation on Solids!
                                      Nuno Moita

                                      Analysing the tutorial they assume that the gasket as the following proprieties:

                                       

                                      - Solid Material: glass gasket;

                                      - Surface Wall: Commercial Aluminium as set in the begining (wizard) - and this is strange to me.. it means that the considered gasket as the same behavier for the radiation as a aluminium set in the begining!

                                       

                                      Got the idea when working with radiation all surface should be set. In the case of the tutorial to not make users confused I would set a non radiation surface or a gasket radiation.

                                       

                                      Thank you very much for your support. Hope this helps other users too.

                                       

                                      regards,

                                       

                                      Nuno

                                        • Re: Defining Radiation on Solids!
                                          Jared Conway

                                          does the gasket see radiation? if it doesn't, then this is a moot point

                                          what is the radiative properties of the gasket? maybe it is the same as aluminum. if that is the case, then it will work properly and requires less work to create a radiative surface that is different.

                                           

                                          what i think youv'e run into is one of the reasons we recommend people attend reseller training on the tools. when you just go through the steps, the process is usually straight forward but doesn't tell you the "why". we actually go beyond that here at hawk ridge systems and do application specific training where we cover all the assumptions and recommendations.