13 Replies Latest reply on Oct 3, 2013 5:39 AM by Jack Gu

    Cpu cooler for notebook

    Jack Gu

      Hi,everyone

           I have question for seting boundary conditions

      At first, this is my model

      未命名1.png

               According to the example,i know set the boundary conditions in inlet and outlet

      this fan 3600rpm,0.17cmm,83Pa=8.3mmaq(static pressure), i set (outlet pressure is biger than inlet)

               But the result is wrong,未命名2.png

       

      frome this result,we can see that,the air is from outlet into fan,it is impossible,is i need to set outlet pressure small than inlet??

      I see the teaching video,it teaching must set from my original set

       

       

       

       

      please help me ,what should i do

       

       

      this is my e-mail:jack77823@gmail.com

       

      thanks

        • Re: Cpu cooler for notebook
          Jared Conway

          hi jack, let's take a step back

           

          1. do you want to perform and internal or external analysis?

          2. what is the inlet to your model? how did you apply it?

          3. what is your outlet? how did you apply it?

           

           

          if you're performing an internal analysis and you have a fan, usually people have an external outlet fan or external inlet fan with a fan curve specified. or they use a volume flow rate. the pressure is usually environmental because that is what is on the other side of the fan.

           

          then on the other end, they have environmental pressure applied to tell the software where the air leaves. set it to atmosphere.

           

          if you have 2 pressures specified, you're forcing the direction and flow rate.

            • Re: Cpu cooler for notebook
              Jack Gu

              At first thank for your answer

              1.internal analysis

              2.and 3.in this picture

               

              未命名1.png

              For ansysis the notebook's Cpu and Gpu cooling.

              i choose the Centrifugal fan for work the air ,so that the air have pressure drop

              i have double inlet hole,so i choose inside faces with environment 10332.2745mmH2O,and outlet hole with environment10332.2745+8.3

              mmH2O,because 83pa=8.3mmH2O

               

              I see the video,it teatch choose insert-fan,three types ,but i don't know what i choose?Radial?fan curve?

               

              So i use another way,use" Rotating Region" with  3600rpm,"inlet" "outlet",and "real wall"

               

              I choose real wall,because the air will throught in the box,the air will contact Gpu,Cpu,hot sink,mother board,

               

              I had been buy "An Introduction to SolidWorks Flow Simulation 2012" John E. Matsson, Ph.D.,but it not help for me

              I am very disappointed for that,there is no  similar example can learn

               

              Could you help me?  Introduction some handbook about use fan for cooling the Electronic Devices

               

               

              I'm verry appreciation for you answer my questions,Thanks

               

                • Re: Cpu cooler for notebook
                  Jared Conway

                  i would take a step back

                   

                  build a box with a hole in it

                  fill that hole with a part

                   

                  cut another hole fill it with a part

                   

                  for the first hole, apply a fan curve to it so you can see how it works

                   

                  on the other hole, make it an environmental pressure

                   

                  i would recommend getting the hang of this before you move onto a rotating region. this is only necessary if you are designing the fan blades.

                   

                  if you're using a centrifugal fan, why not use the radial fan option?

                    • Re: Cpu cooler for notebook
                      Jack Gu

                      I have big Problem.............

                      未命名.png

                       

                       

                      is not laying on the boundary between solid and fluid region.

                       

                       

                       

                      this Problem is very usually happrn,i saw the web,and i check Geometry and Interference

                       

                       

                       

                       

                       

                      未命名3.png

                       

                      you can see the Interference created by rotation area,but is not importment

                       

                      may be you will say the modle is not a cavity ,but i very shure it is a cavity

                       

                      未命名4.png

                        • Re: Cpu cooler for notebook
                          Jared Conway

                          hi, i would recommend checking this article:

                           

                          http://www.hawkridgesys.com/blog/flow-simulation-4-starting-flow-simulation-analysis/

                           

                          you don't have a closed volume so internal analysis won't work.

                           

                          i would recommend you start smaller and with a sample part. in this case you probably have an interference between components that is causing a problem.

                            • Re: Cpu cooler for notebook
                              Jack Gu

                              at first ,thank for your answer ,i find the right ways

                               

                               

                               

                              but now i still suffer big problem

                               

                              the mesh generationabnormally thrminateal未命名19.png

                               

                              all of the set can be run,so my Geometry is right

                               

                              i saw yor answer another people,if you can tue the boundary condiction,

                              at first that you can run and withresult

                               

                               

                              but this problem ,i can not generation mesh at the begin

                                • Re: Cpu cooler for notebook
                                  Jared Conway

                                  suggest suppressing all components except for the outside components, see if it works

                                  then add another part, see if it works

                                   

                                  this will help you identify which part is the problem

                                    • Re: Cpu cooler for notebook
                                      Jack Gu

                                      you are so smart

                                       

                                       

                                      I try it ,thanks

                                      • Re: Cpu cooler for notebook
                                        Jack Gu

                                        thanks i find  the problem

                                         

                                         

                                        This problem is happen in the rotation area..

                                         

                                        my rotanon area is an Assembliesn,it consider fan and with solid rotation area

                                         

                                        see the picture未命名.png

                                         

                                         

                                         

                                         

                                         

                                        at first ,the rotation area is solid ,but the solideworks do't let me mesh the mold

                                         

                                        but when i use Molding,which the solid have some empty places with the fan ,

                                        and then the mesh can be run ,it so amazy,do you know why??

                                         

                                        I'm verry happy when it succeed,but i  wound know why?

                                         

                                         

                                        Thanks,in this day you help so mutch

                                         

                                        This  flow simulation ,is your creating  ?  

                                          • Re: Cpu cooler for notebook
                                            Jared Conway

                                            Going back to some initial comments, unless you are designing the fan, a rotating region is overkill and there are several rules you need to follow to get good results.

                                             

                                            For your problem, it sounds like you come from another cfd software. In flow you model the impeller and then a simple revolve that is solid for the rotating region. No cavity function or subjection.

                                             

                                            I would recommend taking a look at the solving engineering problems document if you want to go this way.

                                              • Re: Cpu cooler for notebook
                                                Jack Gu

                                                At first thanks, for your answer

                                                 

                                                 

                                                 

                                                I am a student now,my project is "backward curved centrifugal fan"

                                                 

                                                 

                                                 

                                                I want to discuss about "rotational area" with you

                                                 

                                                速度場.png

                                                 

                                                 

                                                 

                                                Whe you see the picture,you will found that the rotational area is not complete contain the fan,the left side

                                                 

                                                 

                                                In general teaching movie,it just only tell write a solid cylinder,but it's  inaccurate

                                                 

                                                 

                                                風扇模型.pngrotation area.png未命名1.png

                                                 

                                                This is my fan model,and this is my rotational area,i use Rotating packed

                                                 

                                                And it is  impossible complete contain the fan, without the rotation area just match  than fan ,it means, it

                                                must bigger than fan

                                                This result can't be accepted,because this fan is very tiny,it only 60mm

                                                 

                                                 

                                                 

                                                So i hople  you teatch me the skill ,that can write the rotation area just match with my fan

                                                 

                                                 

                                                 

                                                 

                                                 

                                                Please tell me the answer,or give me some suggestion

                                                 

                                                 

                                                 

                                                Thank you very mutch!!!