Question on Collision Energy and Power Consumption

Clemenslischka

Hi,

from basic collisions theory we can estimate the maximum collision energy as E = (m_1*m_2) / 2*(m_1+m_2) * v_rel_coll^2. If i calculate this energy transfer for all collisions with relative collision velocity that happen in 1 second i arrive at a value that is circa 2-12% of the value EDEM gives me for the average power consumption of the geometry my particles are in contact with at a specific rotaional velocity. How do i interpret this result? Is the power value higher because of friction loss or particle torque?

Thanks!!

Stefan Pantaleev_21979

Hi Clemens,

You are correct that there are large energy losses due to friction and less significant but not negligible losses due to viscous and non-viscous damping. Depending on the solid fraction, stress state and flow regime in the particle assembly as well as the frictional properties of the particle contacts, the frictional energy loss (the work of friction) can range from a small fraction to nearly all of the energy loss. Beyond collisional energy there may be potential energy gains that also require external energy input (think of an excavator bucket lifting static material for example) as well as inertial effects.

May I ask what the system you are modelling is? 

You can export the collisional energy loss from EDEM (integral of the work of friction and damping over the collisions lifetime) if you have the track collisions option in the solver enabled and you can solve on CPU. This energy loss per unit of time should equal the geometry power at steady state (assuming no inertial effects or changes in potential energy).

Best regards,

Stefan