Large Large Eddy Simulation Model Development for Turbulent Dispersed Gas-Solid Flows

• Applicant: Professor Dr. Berend van Wachem
• Subject Area: Fluid Mechanics ; Mechanical Process Engineering
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 457509672

Most industrial and natural processes with particle-laden flows involve a turbulent flow field. These particle-laden turbulent flows can usually be accurately predicted in numerical simulations resolving the smallest turbulent length and time scales down to the Kolmogorov scales and tracking each particle individually in an Euler-Lagrange framework. For most realistic processes, however, such a direct numerical simulation (DNS) is unfeasible due to the tremendous amount of required computational resources. A common alternative to fully resolving the turbulence in single-phase flows is to perform so-called large eddy simulations (LES), which resolve the largest flow structures and account for the effect of the small flow structures by suitable subgrid-scale models. Although well established in single-phase flows, LES are not directly applicable to particle-laden flows because the small flow scales, which are not resolved in an LES, significantly influence the particle behavior. Furthermore, the particles modify the unresolved turbulent flow structures, which is why the closure models of single-phase LES are not applicable to particle-laden flows. In the first funding period, we have developed novel LES models applicable to turbulent particle-laden flows in unconfined domains. In the next funding period, we aim to develop LES models for particles in wall bounded flows. In this proposal, we will address the three essential problems of LES of particles in wall-bounded turbulence: (i) reconstruction of the subgrid-scale fluid velocity field to obtain accurate particle statistics in one-way coupled simulations, (ii) modeling the effect of the particles on the resolved and unresolved turbulence to accurately predict the turbulence statistics in two-way coupled turbulence, and (iii) predict the correct particle collision statistics in 4-way coupled turbulence.

• DFG Programme: Research Grants