Axial turbine stage simulation setup

- April 5, 2019 at 1:27 pm
  
  lukav
  Subscriber
  
  Hi all,
  
  I am trying to create a model of one axial turbine stage, simulating stator (2 blades) and rotor (1 blade). I have two separate meshes for both and I am using a mixing plane between them with periodic rotating boundaries at the sides. I define rotor cell zone as rotating using Frame motion and 995 rad/s rotational velocity. I assign rotor blade and hub as Moving wall - Relative to Adjacent cell zone with 0 rad/s (so they move with the same velocity as the rotor cell zone) and rotor casing as Moving wall with Absolute motion of 0 rad/s of rotating speed (so it is stationary). Whole stator zone is defined as stationary.
  
  I use Spalart Allmaras turbulence model (although I tried others and it didn't work) and pressure inlet at stator inlet and pressure outlet at rotor outlet. Mixing plane defines coupling on stator outlet and rotor inlet.
  
  The problem is that my case just doesn't work. I really don't understand what else it to define. I tried various things, turbulence models, discreatization schemes, orders of accuracy, even decreasing relaxation factors and gradually increasing rotational velocity.
  
  I even made simplest case, inviscid without any rotation and that failed as well. I somehow feel that the problem is by joining these two meshes (stator and rotor) but on some cases that somehow start to work I have normal transfer of flow through mixing plane. I just don't understand what is going on with this case. I refined my rotor mesh and case doesn't even want to start anymore, not even inviscid.
  
  This is my geometry with rotor blade and hub rotating around x-axis in negative y direction.
  
  Thanks