1. A Coupling Algorithm for Eulerian- Lagrangian Simulation of Dense Gas- Solid Reacting Flows on Unstructured Mesh Jian Cai Assistant Professor University of Wyoming jcai@uwyo.edu

2. Combustion research at UW  New combustion program □ Mechanical Engineering Department □ Four junior faculty members □ Coal utilization  Research topics □ Laser spectroscopy □ Turbulent combustion experiments and modeling □ Pulverized and dense coal combustion □ Radiation modeling and measurements 2

3. Coal combustion and gasification  What is the limiting factor for accuracy?  What is the next limiting factor? 3 TurbulenceRadiation MultiphaseChemistry

4. E-L models for multiphase flows  Advantages in accounting for changes of □ Particle size and distribution  Heat transfer  Heterogeneous reactions □ History between different particles  Composition  Temperature  Disadvantages □ Computational cost □ Unknown surface properties 4

5. OpenFOAM  Lagrangian existing capabilities □ Pulverized coal combustion □ Collisional non-reacting particles  Eulerian □ Solving transport equations □ Needs a new coupling algorithm 5

6. FVM: unstructured collocated mesh 6

7. Coupled equations ModelCoupling variables IncompressibleU, p CompressibleU, p, T, ρ Multiphase compressibleU, p, T, ρ, ε 7

8. Coupling algorithm 8 Energy, species equations + Equation of state Density update Velocity-pressure coupling

9. Reacting test case 9  Pseudo 2D  DPM  Char 2.5mm  24750 parcels  3s physical time

10. CFB  Zhou et al CES 1994 1995  MPPIC  Sand 213µm  0.3Mparcel x 1000p/parcel 10

11. Particle volume fraction 11

12. Conclusions  Eulerian-Lagrangian coupling algorithm □ Unstructured collocated mesh □ Gas-solid dense reacting flows  Computational cost is the major limitation □ MPPIC faster than DPM 12