Anaerobic Biogas Digester Modelling Using OpenFOAM and Fluent Andrew Coughtrie Civil Engineering Biogas Digestion? Problem Definition • Waste Treatment • Mixing effectiveness • Failure when scaled up • Difficult to monitor experimentally Experimental bench scale internal airlift loop biogas digester.* * Karim k. et al.  Gas-lift Digester Configuration Effects on Mixing Effectiveness CFD • Structured square mesh • Ansys Meshing and BlockMesh • Approximation for inlet boundary Slurry Surface Inlet Outlet Walls Problem Setup • Inlet boundary condition based on approximation of flow velocity • RNG k-epsilon turbulence model • Zero shear wall at surface OpenFOAM Control Linear solver Discretisation Schemes Function to monitor velocity Fluent Wall Treatment Standard Wall Functions Scalable Wall Functions Enhanced Wall Treatment Fluent vs. OpenFOAM OpenFOAM *Karim k. et al.  Flow Pattern Visualization of a Simulated Digester Fluent OpenFOAM Fluent Experimental* Single-phase vs. Multiphase DPM Single-Phase Ongoing Work • Non-Newtonian fluid modelling • Comparison between single and multiphase for OpenFOAM and Fluent • Multiphase 3D modelling • Euler-Euler Multiphase using OpenFOAM Three-Dimensional • Full 3D geometry for DPM • Import mesh to OpenFOAM for use with bubbleFoam Questions?