AMS 599 Special Topics in Applied Mathematics

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