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 Slide 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 Slide 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 Slide 4 Genesis (early 1990s)
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
1996199719981999200020022004 2006 Slide 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. Slide 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 Slide 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) Slide 8 TNF Workshop Web Issues ?
Slide 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 Slide 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 Slide 11 Current Status on Piloted Flames Thorough
parametric studies of model sensitivity in RANS/PDF Popes group at
Cornell Combinations of different mixing models and mechanisms 100s
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 Slide 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 Slide 13
TNF8 Workshop (2006) Comparison Table for BB and Swirl Prepared by
Andreas Kempf Slide 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 Slide 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! Slide 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 Slide 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 Slide 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 Slide 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) 1551-1558. Slide 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) 507-523. Slide 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) 701-709. Strain Rate Six
Frames of OH PLIF, t = 30 s CH 4 /H 2 /N 2 OH outline DLR-B Slide
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 bcs High-fidelity
(expensive) Combined experimental & computational benchmarks
Coupling Experiments and Simulations Slide 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 = 0.167 DLR A: U JET = 42.2 m/s T JET = 292
K Re d = 15200 U COFLOW = 0.3 m/s T COFLOW = 292 K Photograph of
Experimental Flame Flame Luminosity (800 s) Slide 24 CH 4 /H 2 /N 2
Flames Cross-section of 6-million cell 3D curvilinear grid (80cm x
40cm) 5 10 20 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) Slide 25 Scatter Data (x/d = 10)
Experiment LES Slide 26 Data Capacity Requirements for LES and DNS
Unformatted data: Primitives: Q = [, u, v, w, e t, Y 1, , Y 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 Slide 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 Slide 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, 100s 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 scienceO(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 Slide 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
