Fluistcom Project Meeting

1. Fluistcom Project Meeting Belfast 24th of DecemberFLUISTCOM Exchange Program at SIEMENS-Muelheim Daniele Panara

2. Overview • MC Fellow Activity during the Fluistcom Exchange Program in Siemens-Muelheim • Transfer of Knowledge Between Academia and Industry • Siemens ITS-Test Rig validation Project • Project Status Description • Mismatches with Experimental Data • New Strategies of Investigation • Siemens Experiences • Improved Diagonal Swirler Model • Fellow Experiences • Improved Boundary Layer Modeling • Unsteady Wall Heat Transfer Effects • Improved Results

3. ITS Test Rig, V64.3A burner • Experimental Results of the Reacting Steady Flow • Velocity Measurements (LDA) • Temperature Measurements (Thermocouple Probe) • Heat Transfer at Combustor Walls (Ceramic Tile with Thermocouples) • Flame Front Detection (2D-OH-LIF) • Operating Conditions • Atmospheric pressure • Equivalence Ratio 0.5 • Premixed Operation with 7% Pilot Gas Injection V64.3A burner Air Air

4. Numerical Model Description Original Simulation: • Chemistry: • Eddy Dissipation Model • Two Step Chemistry: • CH4, CO, CO2, H2O, N2 • Turbulence: • k-ε Turbulence Model • Scalable Wall Functions ( ) • Radiation: • Discrete Transfer Model • Weighted Multigray Sum of Gas Species • Fluid Frozen in a Converged Convective Alone Steady State Solution • Number of Ray per Element 8 • No use of Coarser Radiation Grid • Radiation Calculation for each Time Step

5. Numerical Model Description Original Simulation: • Inlet BC: • Axial Swirler: • Velocity Profiles Interpolated • Radiation: black body at local T

6. Numerical Model Description Original Simulation: • Inlet BC: • Diagonal Swirler: • Velocity Profiles Interpolated • Averaged Premixed Flow • Radiation: black body at local T

7. Numerical Model Description X0 Original Simulation: t • BC Liner Walls: • heat transfer coefficient • radiation X0

8. Numerical Model Description X0 Original Simulation: t • BC CJHT Liner Wall: • Outer Wall Fixed Temperature: • radiation X0 • BC Outlet: • Static Pressure • Radiation: black body at averaged exit temperature

9. Existing Missmatches Between ITS Experimental Data and Numerical Results Temperature Profile Hot Side Ceramic Tile Flame Temperature Profile X=0.2257 x/D Z=Y=0

10. New Strategies of Investigation • Siemens Experiences • Result Sensibility analysis • Reactive Flow-Radiation Interaction • Radiative outlet properties • Temperature Effects on Ceramic Properties • Emissivity • Conductivity • Turbulence Modeling • Improved Diagonal Swirler Model • Fellow Experiences • Improve Boundary Layer Resolution • Low Reynolds Number Turbulence Modeling • Unsteady Wall Heat Transfer Effects

11. Sensitivity Analysis Radiation: Use of Coarser Grid for Radiation No Frozen Flow, Radiative Solution each 10 Time Steps • Lesson Learned • Small Effect on Near Flame Temperature Profile • No Effect on Wall Temperature • Coarsening Rate is Accurate and Effective to Save • Computational Time

12. Sensitivity Analysis Radiation: Effect of Radiative Outlet Temperature • Lesson Learned • High Impact of Outlet Radiative Boundary Conditions on Wall Temperature • No Effect on Near Flame Temperature Profile

13. Sensitivity Analysis Radiation: Effect of the dependence of Ceramic Emittance on Temperature • Lesson Learned • Small Effect on the Dependence of Ceramic Emittance on Temperature • No Effect on Near Flame Temperature Profile • Opposite Trend are Found Depending on the Choice of Dependency Law

14. Sensitivity Analysis Radiation: Effect of the Turbulence Modeling (Coarse Grid) • Lesson Learned • Small Differences Depending on The Choices of Turbulence Modelling • Best Results seem to be obtained using k- SST • Open Questions • What is the effect of near wall grid refinement?

15. Diagonal Swirler Simulation

16. New Grid • Improved Boundary Layer Resolution • For Low Reynolds Number Turbulence Modeling • Four Wall CJHT • Extended Outlet Section • New Diagonal Swirler • Inlet Conditions

17. Results Effect of New Geometry + Diagonal Swirler Inlet BC With Radiation

18. Effect of Errors in Thermocouples Positioning Effect of New Geometry + Diagonal Swirler + Radiation

19. Unsteady Computation • 20Hz ‘Small’ Oscillations • Unsteady effects confined in corner regions

20. Unsteady Computation

21. Unsteady Computation Ceramic Wall Temperature • Radiation • Non Reflecting BC • displacement error: • +0.1mm

22. Unsteady Computation Ceramic Wall Temperature • Radiation • Non Reflecting BC • displacement error: • +0.2mm

23. Unsteady Computation Near Flame Temperature Profile • Radiation • Non Reflecting BC

24. Conclusions • MC Fellow Activity during the Fluistcom Exchange Program in Siemens-Muelheim • Transfer of Knowledge Between Academia and Industry • Considering a wall probe displacement error of +0.2mm good agreement between numerical and experimental results has been found. • An improvement of the numerical results in the near flame region has been obtained • Some unsteady flow effects have been found but seem to little affect the wall temperature and flame temperature profile

25. Questions