AMS 599 Special Topics in Applied Mathematics Lecture 4

AMS 599Special Topics in Applied

MathematicsLecture 4

James GlimmDepartment of Applied Mathematics

and Statistics,Stony Brook University

Brookhaven National Laboratory

Turbulent mixing for a jet in crossflow and plans

for turbulent combustion simulations

The Team/Collaborators• Stony Brook University

– James Glimm– Xiaolin Li– Xiangmin Jiao– Yan Yu– Ryan Kaufman– Ying Xu– Vinay Mahadeo– Hao Zhang– Hyunkyung Lim

• College of St. Elizabeth– Srabasti Dutta

• Los Alamos National Laboratory– David H. Sharp– John Grove– Bradley Plohr– Wurigen Bo– Baolian Cheng

Scramjet Project

– Collaborated Work including Stanford PSAAP Center, Stony Brook University and University of Michigan

Schematics of the transverse injection of an under-expanded jet into a supersonic crossflow

• Structures expected: bow shock, counter-rotating vortex pair, recirculation zones, large scale structures on the jet surface

Outline of Presentation

• Problem specification and dimensional analysis– Experimental configuration– HyShot II configuration

• Plans for combustion simulations– Fine scale simulations for V&V purposes– HyShot II simulation plans

• Preliminary simulation results for mixing

Main ObjectiveMain Objective• Compare to the Stanford code development

effort. Chemistry to be computed without a model (beyond dynamic turbulence model). Hereby we can offer a UQ assessment of the accuracy of the Stanford code.

• If the comparison is satisfactory and the two codes agree, the UQ analysis of the Stanford code (in this aspect) will be complete.– Applications to the UQ program

Problem Specification andProblem Specification andDimensional AnalysisDimensional Analysis

• Simulation Parameters: Experimental ConfigurationSimulation Parameters: Experimental Configuration– Fine grid: approximately 60 micron gridFine grid: approximately 60 micron grid

• Mesh = 1500 x 350 x 350 = 183 M cellsMesh = 1500 x 350 x 350 = 183 M cells– If necessary, we can simulate only a fraction of the experimental If necessary, we can simulate only a fraction of the experimental

domaindomain– If necessary, a few levels of AMR can be usedIf necessary, a few levels of AMR can be used– Current simulations = 120 microns, about 10 M cells Current simulations = 120 microns, about 10 M cells

• HyShot II configurationHyShot II configuration– Resolution problem is similarResolution problem is similar

• 3/4 volume after symmetry reduction compared to experiment3/4 volume after symmetry reduction compared to experiment– Full (symmetry reduced) domain needed to model unstartFull (symmetry reduced) domain needed to model unstart– Resolved chemistry should be feasibleResolved chemistry should be feasible– Wall heating an important issueWall heating an important issue

Flow and Chemistry RegimeFlow and Chemistry Regime• Turbulence scale << chemistry scaleTurbulence scale << chemistry scale

– Broken reaction zoneBroken reaction zone• Autoignition flow regimeAutoignition flow regime

– TTcc << T << T– Makes flame stable against extinction from turbulent fluctuations Makes flame stable against extinction from turbulent fluctuations

within flame structurewithin flame structure• Unusual regime for turbulent combustionUnusual regime for turbulent combustion

– Broken reaction zone autoignition distributed flame regimeBroken reaction zone autoignition distributed flame regime– Query to Stanford team: literature on this flow regime?Query to Stanford team: literature on this flow regime?

• Knudsen and Pitsch Comb and Flame 2009Knudsen and Pitsch Comb and Flame 2009• Modification to FlameMaster for this regime?Modification to FlameMaster for this regime?

– Opportunity to develop validated combustion models for this Opportunity to develop validated combustion models for this regime, for use in other applicationsregime, for use in other applications

• Some applications of DOE interestSome applications of DOE interest

Flow, Simulation and Chemistry Flow, Simulation and Chemistry Scales; Experimental RegimeScales; Experimental Regime

• Turbulence scale << grid scale << chemistry scaleTurbulence scale << grid scale << chemistry scale• Turbulence scale = 10 micronsTurbulence scale = 10 microns• << grid scale = 60 microns << grid scale = 60 microns • << chemistry scale 200 microns<< chemistry scale 200 microns

• Resolved chemistry, but not resolved turbulenceResolved chemistry, but not resolved turbulence• Need for dynamic SGS models for turbulenceNeed for dynamic SGS models for turbulence• Transport in chemistry simulations must depend on Transport in chemistry simulations must depend on

turbulent + laminar fluid transport, not on laminar turbulent + laminar fluid transport, not on laminar transport alonetransport alone

Simulation Plans:Simulation Plans:HyShot II RegimeHyShot II Regime

• Compare to laboratory experimental regime and Compare to laboratory experimental regime and resolved chemistry simulations (V&V)resolved chemistry simulations (V&V)

• Simulate in representative flow regimes defined by the Simulate in representative flow regimes defined by the large scale MC reduced order model, both for failure large scale MC reduced order model, both for failure conditions (unstart) and for successful conditions.conditions (unstart) and for successful conditions.

• Provide improved combustion modeling to the MC low Provide improved combustion modeling to the MC low order model, for the next iteration of an MC full system order model, for the next iteration of an MC full system search.search.

• Investigate “gates” which serve to couple system Investigate “gates” which serve to couple system components into full systemcomponents into full system– For combustion chamber: fuel nozzle, inlet flow and exit nozzleFor combustion chamber: fuel nozzle, inlet flow and exit nozzle

• Exactly how can the “gate” be defined to achieve the decoupling?Exactly how can the “gate” be defined to achieve the decoupling?– Essential step for relating UQ of components to UQ of full Essential step for relating UQ of components to UQ of full

systemsystem

Preliminary Simulation Results:Preliminary Simulation Results:Mixing OnlyMixing Only

3D simulation. 67% H2 mass concentrationisosurface plot compared to experimental OH-PLIF image (courtesy of Mirko Gamba). The grid is 120 microns, 2 times coarser than the Intended fine grid mesh size.


Black dots are the flame frontextracted from the experimentalOH-PLIF image.


Velocity divergence plotted at the midline plane. Bow shock, boundary layer separation, barrel shock and Mach disk are visible from the plot.


HH22 mass fraction contour plotted at the midline plane


Stream-wise velocityStream-wise velocity contour plotted at the midline plane


HH22 mass fraction contour plotted at x/d=2.4


Stream-wise velocityStream-wise velocity contour plotted x/d=2.4


Comparison between Smagorinsky model (left) and dynamic model (right)Comparison between Smagorinsky model (left) and dynamic model (right) Mass fraction plot, using 240 micron gridMass fraction plot, using 240 micron grid


Comparison between 240 micron grid (left) and 120 micron grid (right) Comparison between 240 micron grid (left) and 120 micron grid (right) with dynamic model, mass fraction plotwith dynamic model, mass fraction plot

Future Work

• Improve code capability– Add missing physics– Add Chemistry

• Validation Study (comparison with existing experiments, such as HyShot II ground experiments, and Stanford Mungal jet-in-crossflow experiments)

• UQ/QMU analysis

Documents

AMS 599 Special Topics in Applied Mathematics Lecture 4