Particles are leaving from pressure outlet boundary_How the equations are balanced in such case?

I have modelled fluidised bed, where I have given high inlet velocity. I have observed that the particles are exiting from the pressure outlet boundary. I ran the software till all the particles got removed from the domain.
My question is how the equations are balanced if all the particles are getting removed from the domain?

Hi @margidave007 - welcome to MFiX
What do you mean by “how the equations are balanced” - which equation in particular?