Here I am going to explain the method to simulate the centrifugal compressor, the long awaited blog. Main attraction of this blog is to demonstrate the technique to handle the CAD model with blades and hub only imported as IGES/Step or parasolid file. Usually people convert the IGES or parasolid file in turbogrid (*.tur) format and get high quality hexa mesh in Turbogrid. The main problem with this approach:
1. Consistency problem. Different people may get different blade shape, casing and hub profile.
2. No easy / straight forward approach. I have been using Gambit to get coordinates. And some also use Gridgen or other softwares long with excel to do this work. While working in Gambit there are number of times when files get corrupted and some times Gambit crashes and wasting efforts of days (sometimes even weeks). There is also problem of persistence e.g. If some one want to change the number of profiles along span from two to five or ten. In Gambit or Gridgen it means starting from scratch each time.
3. Gambit and gridgen do not support extensive geometric operations while designmodeler provides CAD like environment.
Brief steps are :
1. Open workbench and drag the geometry icon into main window and open the designmodeler.
2. Apply operations in blade modeler mode of DM like creating flow passage and export points.
3. Open Turbogrid and use ATM optimized approach for best quality mesh.
4. Process mesh in CFX-Pre like setting up solver parameters, boundary conditions and turbulence model.
5. Start solver and solve problem
6. Post process results.