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Perspectives from the TNF Workshop Robert S. Barlow Combustion Research Facility Sandia National Laboratories Robert S. Barlow Combustion Research Facility.

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Presentation on theme: "Perspectives from the TNF Workshop Robert S. Barlow Combustion Research Facility Sandia National Laboratories Robert S. Barlow Combustion Research Facility."— Presentation transcript:

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

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

4  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 (H 2, CO, CH 4 ) 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 TNF Workshop – Basics NaplesHeppenheimBoulderDarmstadtDelftSapporoChicago Heidelberg

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, bSimple jet flames  c, dPiloted jet flames  eBluff-body  fBluff-body/Swirl  gLifted flame in vitiated coflow  hOpposed jet flame  iUnconfined swirl flame  jEnclosed swirl flame  kPremixed low-swirl flame  lPremixed swirl, bluff-body  mEnclosed 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 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: ( 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 TNF3 Workshop (1998) – Classic results for Flame D PDF, CMC, ILDM steady flamelet, … laser axis laser axis x/d =45 x/d =30 x/d =15 x/d =7.5 x/d = 2 Premixed Pilot Flame

10 TNF4 Workshop (1999) – Example Comparisons Axial and radial profiles: U, u’, F, F’, T, T’ Conditional means: T, O 2, CO 2, CO, H 2 O, H 2, CH 4, OH, (NO) T scatter plots

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 TNF8 (2006) Target Flames and Phenomena  Bluff-Body Stabilized  Sydney University, Sandia  High velocity coflow, central fuel jet  Flow recirculation  CH 4 /H 2, CH 4 /air, CO/H 2  Swirl/Bluff-Body  Sydney Univ., Sandia  Large-scale instability  Vortex breakdown  CH 4, CH 4 /air, CH 4 /H 2 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 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 8 laser 5 cameras 7 computers Combined measurement:  T, N 2, O 2, CH 4, CO 2, H 2 O, H 2, CO  220-  m spacing, 6-mm segment  state of mixing (mixture fraction)  progress of reaction  rate of mixing (scalar dissipation)  local flame orientation Instantaneous thermochemical state and local flame structure

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 CH 4 /H 2 /N 2 (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  m sample spacing, 50  m optical) Conditional Mean  DLR-B, x/d=10

19 More Piloted Jet Flames  Piloted CH 4 /H 2 /air jet flames Collaboration with Henri Ozarovsky and Peter Lindstedt (Imperial College) High Reynolds number (60,000 and 67,000);  = 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)

20 Simultaneous Planar Imaging: Scalar Dissipation  Temperature, T  Mixture fraction,   Forward reaction rate, [CO] + [OH]  [CO 2 ] + [H]  Scalar dissipation,  J.H. Frank, S.A. Kaiser, M.B. Long, Combust. Flame 143 (2005)

21 High-Speed Multi-Frame OH PLIF Imaging + Stereo PIV J. Hult, U. Meier, W. Meier, A. Harvey, C.F. Kaminski, Proc. Combust. Inst. 30 (2005) Strain Rate Six Frames of OH PLIF,  t = 30  s CH 4 /H 2 /N 2 OH outline DLR-B

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

23 CH 4 /H 2 /N 2 Flames Nozzle: d INNER = 8.0 mm, tapered to sharp edge Fuel: 22.1% CH 4, 33.2% H 2, 44.7% N 2 Coflow: 99.2% Air, 0.8% H 2 O Stoichiometric mixture fraction: Z st = DLR A: U JET = 42.2 m/s T JET = 292 K Re d = U COFLOW = 0.3 m/s T COFLOW = 292 K Photograph of Experimental Flame Flame Luminosity (800  s)

24 CH 4 /H 2 /N 2 Flames Cross-section of 6-million cell 3D curvilinear grid (80cm x 40cm) 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)

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

26 Data Capacity Requirements for LES and DNS Unformatted data: –Primitives: Q = [ρ, ρu, ρv, ρw, ρe t, ρY 1, …, ρY N-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 D Flame E 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: 1.Code/algorithm developmentO(10 yrs)Highly specialized enabling algorithms, ongoing development 2.Data productionO(6 mos)Remote supercomputers, high-speed networking, parallel filesystems 3.ValidationO(6 mos)Significant interaction with experi- mentalists/theorists 4.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

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