How to evaluate the torque on a rotating part (Impeller or mixer)?

Hi everybody,
Does anyone know whether it is possible to evaluate the force acting on a rotating body that interacts with both fluid and solid particles and the corresponding torques?

Thank you for your help.

I’m not sure I understand the question. What’s driving the rotation? In a case like the 3D mixer tutorial, you are controlling the speed of the mixer, so you can compute the (constant) torque directly - but I think you may be looking for something else … are you looking for the torque contributions from particle collisions?

Exactly, the moment produced by the rotor that also includes the forces exerted by the particles on the rotating part. In the case that the rotor simply rotates without any interaction with particles only with the medium (air) the torque can be calculated by the product Force X Position [N-m]. But including particles they will introduce extra power consumption by the rotor. Is it possible at all to compute forces exerted on solid (stl) rotating parts?
Thanks Charles.