Hey @fernando_ferro ,
This would be similar to let’s say how a lift is calculated over an aircraft wing. We already have a tutorial about that here: Compressible Flow Around a Wing | Tutorial | SimScale
The force and moments result available under the successful simulation should give you the lift / thrust force generated around the blade surfaces. In the case of the tutorial, pressure force (lift) is in positive Y direction since the model has an orientation of the wing like that (see below images and notice the orientation cube)
In your case, you would have to check the z direction pressure force.
With the boundary conditions you have assigned, it seems to be about 300 N of thrust.
Let us know if you need more support! 
Cheers,
Satvik