A CHT framework for the CFD analysis of the spray-wall thermal interaction in the dosing unit of SCR systems for diesel engines

In this work, a Conjugate Heat Transfer (CHT) framework for the simulation of the full kinematic and thermal interaction of the spray with the walls has been implemented and applied to a test case. Full coupling between the gaseous, spray and liquid film were achieved, allowing to capture the full range of kinematic and thermal interactions between the spray, the wall and the liquid film (both in dry and wet conditions). The evolution of the film is handled through a multi component film model, with a coupling to the gaseous and solid phase. In particular, the coupling of the film with a CHT model of the solid wall allows the designer to have a comprehensive evaluation of the wall temperature evolution. To complete the description of the film evolution, a stripping model for droplets from the film is used, allowing the transfer of mass from the film surface to the lagrangian phase.