1 / 29

Perspectives from the TNF Workshop

Perspectives from the TNF Workshop. Robert S. Barlow Combustion Research Facility Sandia National Laboratories. Support by: DOE Offices of Basic Energy Sciences. Multi-Agency Coordinating Committee on Combustion Research (MACCCR) Workshop on

glenys
Télécharger la présentation

Perspectives from the TNF Workshop

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Perspectives from the TNF Workshop Robert S. Barlow Combustion Research Facility Sandia National Laboratories Support by: DOE Offices of Basic Energy Sciences Multi-Agency Coordinating Committee on Combustion Research (MACCCR) Workshop on Next Steps in Using Combustion Cyberinfrastructure

  2. Perspectives from the TNF Workshop* : Outline • Background • History (>10 years) • What, Why, Who, When • Use of the web • Past use • Types of content • Current status • Future directions • Expanded types of flames • Expended types of data • Expanded size of content • What might Cyber Infrastructure do for TNF? • Needed functionality • Chicken-egg problem * International Workshop on Measurement and Computation of Turbulent Nonpremixed Flames

  3. complex geometry practical combustion systems kinetics turb/chem spray pressure scaling particulates TNF Workshop – Focus Validation of Models for Turbulence/Chemistry Interaction • Progression of well documented cases that are consistent with to the range of current capabilities of current models Simple Jet Piloted Bluff Body Swirl

  4. Naples Heppenheim Boulder Darmstadt Delft Sapporo Chicago Heidelberg 1996 1997 1998 1999 2000 2002 2004 2006 TNF Workshop – Basics • Genesis (early 1990’s) • Incomplete experiments, poorly defined comparisons with computations • Internet offered opportunity for rapid communication, collaboration, data sharing • TNF1 in Naples (1996) established the ground rules • Collaboration of experimental and computational researchers • Core groups: Sandia, Berkeley, Cornell, TU Darmstadt, Imperial College, U Sydney • Framework for detailed comparisons of measured and modeled results • Identify gaps in data and models, define research priorities • Emphasis on fundamental issues of turbulence-chemistry interaction • Nonpremixed and partially premixed flames of simple fuels (H2, CO, CH4) • Progression in complexity of flow field and kinetics • Public (web-based) availability of data sets and comparisons • Primary basis (so far)  point statistics from Raman/Rayleigh/LIF and LDV

  5. TNF Workshop – Themes • “We emphasize that this is not a competition, but rather a means of identifying areas for potential improvements in a variety of modeling approaches.” • “This collaborative process benefits from contributions by participants having different areas of expertise, including velocity measurements, scalar measurements, turbulence modeling, chemical kinetics, reduced mechanisms, mixing models, radiation, and combustion theory.” • TNF8 Organizing Committee • R.S. Barlow, R.W. Bilger, J.-Y. Chen, A. Dreizler, J. Janicka, R.P. Lindstedt, A.R. Masri, J.C. Oefelein, H. Pitsch, S.B. Pope, D. Roekaerts, and L. Vervisch.

  6. Gallery of Turbulent Flame Examples • Figure 1 (Barlow, ProCI 2007) • a, b Simple jet flames • c, d Piloted jet flames • e Bluff-body • f Bluff-body/Swirl • g Lifted flame in vitiated coflow • h Opposed jet flame • i Unconfined swirl flame • j Enclosed swirl flame • k Premixed low-swirl flame • l Premixed swirl, bluff-body • m Enclosed premixed swirl flame • n Premixed jet in vitiated coflow

  7. TNF Workshop – Current Mode of Operation • People • 1 main organizer • a few (~6) active members of the organizing committee • loose ongoing scientific collaborations (roughly 20-30 people in “clumps”) • ~ 80 participants at each workshop (every 2 years) • Budget • no targeted funding for TNF Workshop activities • Sandia (DOE/BES) pays for some admin. support • TU Darmstadt has also contributed admin. support (SFB 568) • Sponsorship used to reduce registration fees for faculty & students • Web Contents: (http://www.ca.sandia.gov/TNF) • very simple site • data sets (compressed ascii files) and submodels (chem, mixing, radiation) • proceedings (PDF) • bibliography • total < 1GB (only point data; no 1D, 2D, 3D; no simulation data)

  8. TNF Workshop – Web Issues ?

  9. x/d =45 x/d =30 Premixed Pilot Flame x/d =15 x/d =7.5 laser axis x/d = 2 laser axis TNF3 Workshop (1998) – Classic results for Flame D PDF, CMC, ILDMsteady flamelet, …

  10. TNF4 Workshop (1999) – Example Comparisons T scatter plots Conditional means:T, O2, CO2, CO, H2O, H2, CH4, OH, (NO) Axial and radial profiles:U, u’, F, F’, T, T’

  11. Current Status on Piloted Flames • Thorough parametric studies of model sensitivity in RANS/PDF • Pope’s group at Cornell • Combinations of different mixing models and mechanisms • 100’s of pages of figures as “supplemental material” • Ten years to really understand the details for set of 3 flames • Other RANS approaches still trying to get extinction right • Only one LES/FDF of flame E (w/ extinction) by V. Raman

  12. Swirl/Bluff-Body • Sydney Univ., Sandia • Large-scale instability • Vortex breakdown • CH4, CH4/air, CH4/H2 TNF8 (2006) Target Flames and Phenomena • Bluff-Body Stabilized • Sydney University, Sandia • High velocity coflow, central fuel jet • Flow recirculation • CH4/H2, CH4/air, CO/H2 Comparisons of measured and modeled results on the Sydney Bluff-Body and Swirl flames coordinated by Andreas Kempf at the TNF8 Workshop

  13. TNF8 Workshop (2006) – Comparison Table for BB and Swirl Prepared by Andreas Kempf

  14. TNF Workshop – Successes • improved quality and availability of experimental data for “simple” flames • higher “standards” for combustion model validation • better understanding of model capabilities and experimental uncertainty • a few very productive collaborations • collaboration & rapid feedback  accelerated progress for same $$ • impact (journal references, use by industry), high visibility • 11/20 nonpremixed modeling papers in PCI 30-31 used TNF data

  15. TNF Workshop – Failures • still very few “appropriate, complete” data sets • comparisons limited to easiest quantities (point statistics) • little information from calculations has been preserved • funding for collaborative experimental work in the US is very limited • currently no model for growth of TNF Workshop beyond “cottage industry” (larger data sets, more complete comparisons, …) • web content editor is way behind!

  16. TNF Workshop – Future Directions and Challenges • Larger experimental data sets • beyond single point statistics • imaging data (PIV, stereo PIV, 2-D and 3-D imaging data) • time domain (high-speed imaging, multi-frame, time series…) • more complex flames (fuel and flow geometry) • Larger simulation data sets • highly-resolved LES of lab-scale flames • basis for comparison?? – lots of work to do here • feature extraction, vis, etc. • Connections to other areas • premixed, soot, pressure effects, multi-phase • educational possibilities • more formal “publication” of results • comparison “engine”

  17. Turbulent Combustion Laboratory Instantaneous thermochemical state and local flame structure Combined measurement: • T, N2, O2, CH4, CO2, H2O, H2, CO • 220-mm spacing, 6-mm segment • state of mixing (mixture fraction) • progress of reaction • rate of mixing (scalar dissipation) • local flameorientation 8 laser 5 cameras 7 computers

  18. New Data Sets Can Take Years to Fully Analyze • Line-imaged Raman/Rayleigh/CO-LIF and Crossed OH PLIF in the “DLR-A” and “DLR-B” flames • CH4/H2/N2 (22.1%, 33.2% 44.7%) • Nearly constant Rayleigh cross section • 8 mm jet exit diameter, 0.3 m/s coflow, ~60 cm flame length • DLR-A: Re = 15,200 DLR-B: Re = 22,800 • High resolution Rayleigh (40 mm sample spacing, 50 mm optical) Conditional Meanc DLR-B, x/d=10

  19. More Piloted Jet Flames • Piloted CH4/H2/air jet flames • Collaboration with Henri Ozarovsky and Peter Lindstedt (Imperial College) • High Reynolds number (60,000 and 67,000); f = 3.2, 2.5, 2.1; total of 18 cases • Increase local extinction in multiple steps Lindstedt, Ozarovsky, Barlow, Karpetis, Proc. Comb. Inst. 31 (2007) 1551-1558.

  20. Simultaneous Planar Imaging: Scalar Dissipation • Temperature, T • Mixture fraction, x • Forward reaction rate, [CO] + [OH]  [CO2] + [H] • Scalar dissipation, c J.H. Frank, S.A. Kaiser, M.B. Long, Combust. Flame 143 (2005) 507-523.

  21. CH4/H2/N2 High-Speed Multi-Frame OH PLIF Imaging + Stereo PIV DLR-B Six Frames of OH PLIF, Dt = 30 ms Strain Rate OH outline J. Hult, U. Meier, W. Meier, A. Harvey, C.F. Kaminski, Proc. Combust. Inst. 30 (2005) 701-709.

  22. TNF Workshop flames Coupling Experiments and Simulations • Direct comparisons with matched bc’s • High-fidelity (expensive) • Combined experimental & computational benchmarks Turbulent Flame Experiments Address key flame phenomena, but provide only partial information Large Eddy Simulation (LES) Resolve energetic scales, but model subgrid scales

  23. CH4/H2/N2 Flames Nozzle: dINNER= 8.0 mm, tapered to sharp edge Fuel: 22.1% CH4, 33.2% H2, 44.7% N2 Coflow: 99.2% Air, 0.8% H2O Stoichiometric mixture fraction: Zst = 0.167 • DLR A: • UJET= 42.2 m/s • TJET = 292 K • Red = 15200 • UCOFLOW= 0.3 m/s • TCOFLOW = 292 K Flame Luminosity (800 s) Photograph of Experimental Flame

  24. Field of view for Kaiser and Frank imaging experiments State of the art (high-quality) grids Distributed multiblock domain decomposition Adaptive mesh capability (R-refinement technique) CH4/H2/N2 Flames Cross-section of 6-million cell 3D curvilinear grid (80cm x 40cm) 20 10 5

  25. Scatter Data (x/d = 10) Experiment LES

  26. Data Capacity Requirements for LES and DNS • Unformatted data: • Primitives: Q = [ρ, ρu, ρv, ρw, ρet, ρY1, …, ρYN-1]T • 8 Bytes/[(Variable)(Grid-Cells)(Time-Step)] • 10 variables, 1-million grid-cells  80 Mbytes/Timestep • Variables: • 10 – 100 (spatial-coordinates + primitives + composite) • Grid size (presently): • O(1 – 10-million) … LES • O(1 – 100-million) … DNS • Typical animation uses approximately 200 frames • Tradeoff between amount of data stored and cost of post-processing on-the-fly • Capacity requirements on the order of terabytes rapidly approached from J. Oefelein

  27. LES-FDF Simulation of Sandia Flames • Simulation details • 256 x 128 x 32 points • 30-50 particles/cell • More than 5K time steps • Data stored • 75 Mb of LES data/timestep • 3.75 Gb of FDF data/timestep • 20 time-stations stored • Mining operations • Sub-filter FDF conditioned on filtered scalar fields • Conditional mixing plots Flame E Flame D from V. Raman, UT Austin

  28. LBNL Laboratory-scale DNS O(10 cm)3 • Lean premixed turbulent flames (V- and slot-flames, and low-swirl burners) • Very large scale simulations, current datasets O(1-10+) TB • Complex detailed chemical mechanisms w/detailed transport, 100’s of reactions • Map simulations onto theory / experiment. • Use simulations to analyze flames beyond traditional theory/experimental approaches • Time-scale of research: • Code/algorithm development O(10 yrs) Highly specialized enabling algorithms, ongoing development • Data production O(6 mos) Remote supercomputers, high-speed networking, parallel filesystems • Validation O(6 mos) Significant interaction with experi- mentalists/theorists • Extraction of “new science” O(1 yr) Analysis framework requires multi-year interactions to relate simulations to experimental diagnostics, theory and beyond Requirements for data analysis - Computing resource intensive, supercomputer CPU/disks/archiving - Complex, specialized data structures specific to the simulation - Data manipulation consistent with simulation (physics databases, discretization) - Manpower intensive (specialized analysis driven by multi-disciplinary interactions) - Coordinate efforts amongst math/computer science, theory, experimental diagnostics

  29. What might Cyber Infrastructure do for TNF Workshop • Collection, packaging, and distribution of large data sets: • Experiments and high-fidelity simulation • Reduce labor by standardizing(?) and automating the upload process • Allow for archiving of model results in digital form • Include functionality to interactively view (plot) data in various ways • Promote formation of more collaborative groups • Pay for people to build/maintain custom tools for data archiving/analysis • Infrastructure is not (currently) the bottle neck for progress in TNF • Interagency collaboration to promote research on targeted problems could be very useful

More Related