[th0masrtg]

Hi,



I am having trouble getting good result on a fluent simulation.


First of all, I am a begginer on ansys, I did have some lectures but it was more a "reproduce what I do" than a real teaching class.


What I am trying to achieve :



I am trying to make an FEA model to compare different fan and later volute design for a centrifugal blower. The design for now is created using solidworks but I have plan on trying to use VISTA to generate blade and volute designs later.


The centrifugal blower opperates at room temperature and at atmospheric pressure. My atmosperic pressure, I mean that the air surrounding the fan is at atmospheric pressure.
I want to set the RPM at which operates the fan, and obtain the air velocity at the outlet.



What have I done :


To validate my FEA model, I bought a centrifugal blower and got the step file from the manufacturer.
1) I have measured the real airspeed (arround 30m/s at the outlet)
2) From the step file, I have modeled the air inside the fan, and created a boolean substraction of the fan to get only one solid being the "mass of air"
3) I have imported this solid into ansys and made this named selection : inlet, fan, wall, outlet.
4) I have generated a mesh using edge sizing to locally refine the mesh and applied a tetrahedron mesh method.
5) I moved on to fluent, and set it like so : Energy on, K epsilon (I left it by default)
6) boundary condition :

pressure inlet : everything by default
pressure outlet : everything by default
fan : fame motion, rotational motion (with the right axis coordinates), and the rotationnal speed of 3000 rpm


by doing so, the outlet air velocity computed form ansys is arround 2-3 m/s.


I beleive I am doing a lot of stuff wrong but I don't know where to start.


thanks in advance, if you prefer screenshots of my settings please ask me.