AMS 599 Special Topics in Applied Mathematics

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Feb 22, 2014 (3 years and 1 month ago)

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AMS 599

Special Topics in Applied
Mathematics

Lecture 4

James Glimm

Department 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 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 and

Dimensional Analysis


Simulation Parameters: Experimental Configuration


Fine grid: approximately 60 micron grid


Mesh = 1500 x 350 x 350 = 183 M cells


If necessary, we can simulate only a fraction of the experimental
domain


If necessary, a few levels of AMR can be used


Current simulations = 120 microns, about 10 M cells


HyShot II configuration


Resolution problem is similar


3/4 volume after symmetry reduction compared to experiment


Full (symmetry reduced) domain needed to model unstart


Resolved chemistry should be feasible


Wall heating an important issue

Flow and Chemistry Regime


Turbulence scale << chemistry scale


Broken reaction zone


Autoignition flow regime


T
c

<< T


Makes flame stable against extinction from turbulent fluctuations
within flame structure


Unusual regime for turbulent combustion


Broken reaction zone autoignition distributed flame regime


Query to Stanford team: literature on this flow regime?


Knudsen and Pitsch Comb and Flame 2009


Modification to FlameMaster for this regime?


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


Some applications of DOE interest


Flow, Simulation and Chemistry
Scales; Experimental Regime


Turbulence scale << grid scale << chemistry scale


Turbulence scale = 10 microns


<< grid scale = 60 microns


<< chemistry scale 200 microns


Resolved chemistry, but not resolved turbulence


Need for dynamic SGS models for turbulence


Transport in chemistry simulations must depend on
turbulent + laminar fluid transport, not on laminar
transport alone


Simulation Plans:

HyShot II Regime


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


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


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


Investigate “gates” which serve to couple system
components into full system


For combustion chamber: fuel nozzle, inlet flow and exit nozzle


Exactly how can the “gate” be defined to achieve the decoupling?


Essential step for relating UQ of components to UQ of full
system

Preliminary Simulation Results:

Mixing Only

3D simulation. 67% H
2

mass concentration

isosurface 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.

Preliminary Simulation Results:

Mixing Only

Black dots are the flame front

extracted from the experimental

OH
-
PLIF image.

Preliminary Simulation Results:

Mixing Only

Velocity divergence plotted at the midline plane. Bow shock, boundary layer

separation, barrel shock and Mach disk are visible from the plot.

Preliminary Simulation Results:

Mixing Only

H
2

mass fraction contour plotted at the midline plane

Preliminary Simulation Results:

Mixing Only

Stream
-
wise velocity

contour plotted at the midline plane

Preliminary Simulation Results:

Mixing Only

H
2

mass fraction contour plotted at x/d=2.4

Preliminary Simulation Results:

Mixing Only

Stream
-
wise velocity

contour plotted x/d=2.4

Preliminary Simulation Results:

Mixing Only

Comparison between Smagorinsky model (left) and dynamic model (right)



Mass fraction plot, using 240 micron grid

Preliminary Simulation Results:

Mixing Only

Comparison between 240 micron grid (left) and 120 micron grid (right)



with 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