# 3.3.5. Summary

A Lagrangian model for particle transport coupled with an Eulerian solution for the gas phase is presented in detail. Models are presented for particle momentum, heat, and mass transfer, including the effects of turbulence on particle dispersion. Particular attention is paid to heat and mass transfer as these aspects are critical to the anticipated applications and they have not been well documented in other references. The heat and mass transfer models account for film temperatures that differ from particle temperatures in a manner that depends on the relative magnitudes of the internal particle heat transfer, the heat transfer to the particle surface from the gas phase, the heat transfer associated with radiative fluxes, and the enthalpies associated with evaporation and combustion around the particle. Both the evaporation and condensation are permitted. A conservative algorithm for coupling the Lagrangian and Eulerian fields is presented covering mass, species, momentum, and energy transfer between two fields. Models are also specified for the interactions of the Lagrangian field with solid boundaries.

A comprehensive plan to verify the implementation of the physics models is also presented. The verification plan touches on the majority of terms in the implemented physics models. Verification tests are provide for particle momentum, trajectories, heat, and mass transfer in various limiting cases for which analytic solutions can be obtained. Verification tests to evaluate the coupling between the Lagrangian and Eulerian fields are also provided. These verification tests are based on the net conservation of mass, species, energy, and momentum.