ABSTRACT
Numerical simulations can be used to fundamentally investigate the fluid–solid interaction inside rotary drums, in an attempt to connect the material properties and operating conditions with the measured results, consequently removing the empiricism toward predictive design and operation. In this chapter, two different numerical approaches to predict the particle dynamics in rotary drums have been discussed, including their advantages and drawbacks: the two-fluid model or Euler–Euler approach, implemented through CFD (computational fluid dynamics) techniques, and the Lagrangian approach, which is implemented by means of the discrete element method (DEM). Furthermore, the drying process modeling inside rotary dryers is also presented (i.e., distributed parameter and lumped parameter models), which simultaneously involves solid transportation and heat and mass transfer based on mass and energy balances for both solid and drying air phases, as well as empirical correlations to estimate the drying kinetics, the equilibrium moisture content of solids, and the heat transfer coefficient.
