Modeling heterogeneous particle deposition and adhesion in turbulent channel flow

The preferential concentration of inertial particles by turbulence leads to heterogeneous deposition patterns in wall-bounded flows. The deposition and ensuing erosion processes are influenced by the wall’s surface properties and the mechanical characteristics of the particles, which themselves vary with free-stream temperature. This phenomenon is particularly relevant in gas turbine engines, where particles such as ash, sand, and dust bypass inertial separators and form glassy deposits on turbine blades, resulting in blade deterioration. Currently, accurate and robust models for particle adhesion under these conditions are lacking; existing models predominantly depend on empirical data tailored to specific material properties and particle sticking mechanisms. This study evaluates force-, energy-, and probability-based approaches to modeling particle adhesion through direct numerical simulations (DNS) of turbulent channel flows. Furthermore, we will present findings on particle deposition and adhesion rates from large-eddy simulations (LES), where turbulence is only partially resolved. This highlights the critical need for Lagrangian subgrid-scale models capable of capturing the instantaneous spatial distribution of particles.