Copyright © Siemens AG 2007. All rights reserved. Fluistcom Project Meeting Belfast 24th of December FLUISTCOM Exchange Program at SIEMENS-Muelheim Daniele

Copyright © Siemens AG 2007. All rights reserved.

Fluistcom Project Meeting

Belfast 24th of DecemberFLUISTCOM Exchange Program at SIEMENS-Muelheim

Daniele Panara

Page 2 Jan-06Copyright © Siemens AG 2007. All rights reserved.

PE324Daniele Panara

Overview

• MC Fellow Activity during the Fluistcom Exchange Program in Siemens-Muelheim

Transfer of Knowledge Between Academia and Industry

• Siemens ITS-Test Rig validation Project

• Project Status Description

• Mismatches with Experimental Data

• New Strategies of Investigation

• Siemens Experiences

•Improved Diagonal Swirler Model

• Fellow Experiences

•Improved Boundary Layer Modeling

•Unsteady Wall Heat Transfer Effects

• Improved Results


PE324Daniele Panara

ITS Test Rig, V64.3A burner

V64.3A burner

Air

Air

Experimental Results of the Reacting Steady Flow

• Velocity Measurements (LDA)

• Temperature Measurements (Thermocouple Probe)

• Heat Transfer at Combustor Walls (Ceramic Tile with Thermocouples)

• Flame Front Detection (2D-OH-LIF)

Operating Conditions

• Atmospheric pressure

• Equivalence Ratio 0.5

• Premixed Operation with 7% Pilot Gas Injection


PE324Daniele Panara

Turbulence:• k-ε Turbulence Model• Scalable Wall Functions ( )

Chemistry:• Eddy Dissipation Model• Two Step Chemistry:

•CH4, CO, CO2, H2O, N2

Numerical Model Description

Original Simulation:

100y

Radiation:• Discrete Transfer Model• Weighted Multigray Sum of Gas Species• Fluid Frozen in a Converged Convective Alone Steady State Solution• Number of Ray per Element 8• No use of Coarser Radiation Grid• Radiation Calculation for each Time Step


PE324Daniele Panara

Inlet BC:• Axial Swirler:

• Velocity Profiles Interpolated

• Radiation: black body at local T


valuesdiscrete edinterpolat fromgiven



cossin

sincos

,

,

,,

,,

axt

axr

ax

axtaxrax

axtaxrax

u

u

w

uuv

uuu



PE324Daniele Panara

Inlet BC:• Diagonal Swirler:

• Velocity Profiles Interpolated

•Averaged Premixed Flow•Radiation: black body at local T





cossin

sincos

,

,

,,

,,

diagt

diagr

diag

diagtdiagrdiag

diagtdiagrdiag

u

u

w

uuv

uuu



PE324Daniele Panara

BC Liner Walls:• heat transfer coefficient

• radiation


)(

valuefixed

)(

xTT

k

TTt

kq

outout

ceramic

outwceramic

w

t

valuefixed

Interpolation of T profile, cold wall side

670

690

710

730

750

770

790

810

830

850

870

890

910

930

950

-0,1 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8

x [m]

T [K

]

X0

X0



PE324Daniele Panara

BC CJHT Liner Wall:• Outer Wall Fixed Temperature:

• radiation


valuefixed

)(

ceramic

outout

k

xTT

t

valuefixed

Interpolation of T profile, cold wall side

670

690

710

730

750

770

790

810

830

850

870

890

910

930

950

-0,1 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8

x [m]

T [K

]

X0

X0

BC Outlet:• Static Pressure• Radiation: black body at averaged exit temperature



PE324Daniele Panara

0

0.2

0.4

0.6

0.8

1

1.2

0 0.1 0.2 0.3 0.4 0.5 0.6

z/D

T/Ta

db

numerical data

experimental data

Existing Missmatches

Between ITS Experimental Data and Numerical Results

Temperature ProfileHot Side Ceramic Tile

Flame Temperature ProfileX=0.2257 x/D Z=Y=0

0.74

0.76

0.78

0.8

0.82

0.84

0.86

0.88

0 0.5 1 1.5 2

x/D

T/T

ad

b

numericalresults

experimentalresults


PE324Daniele Panara

New Strategies of Investigation

• Siemens Experiences

• Result Sensibility analysis• Reactive Flow-Radiation Interaction

• Radiative outlet properties

• Temperature Effects on Ceramic Properties

• Emissivity

• Conductivity

• Turbulence Modeling

• Improved Diagonal Swirler Model

• Fellow Experiences

• Improve Boundary Layer Resolution

• Low Reynolds Number Turbulence Modeling

• Unsteady Wall Heat Transfer Effects


PE324Daniele Panara

0.74

0.76

0.78

0.8

0.82

0.84

0.86

0.88

0 0.5 1 1.5 2

x/D

T/T

adb

Sensitivity Analysis

Radiation: Use of Coarser Grid for Radiation No Frozen Flow, Radiative Solution each 10 Time Steps

0.5

0.6

0.7

0.8

0.9

1

1.1

0 0.1 0.2 0.3 0.4 0.5 0.6

z/D

T/T

adb

numericaldatacoarseingrate 32

experimental data

numericaldatacoarsening rae 10

NumericalDataFrozenFluid

Lesson Learned

• Small Effect on Near Flame Temperature Profile• No Effect on Wall Temperature• Coarsening Rate is Accurate and Effective to Save Computational Time


PE324Daniele Panara


Radiation: Effect of Radiative Outlet Temperature

1300

1350

1400

1450

1500

1550

1600

0 0.1 0.2 0.3 0.4 0.5 0.6

x/D

T/T

ad

b

numericalresults outBB 800K

experimental results

numericalresults outBB local T

0.5

0.6

0.7

0.8

0.9

1

1.1

0 0.1 0.2 0.3 0.4 0.5 0.6

z/D

T/T

ad

b

numericaldata out BB800K

experimentaldata

numericaldata out BBlocal T

Lesson Learned

• High Impact of Outlet Radiative Boundary Conditions on Wall Temperature• No Effect on Near Flame Temperature Profile


PE324Daniele Panara

0.5

0.6

0.7

0.8

0.9

1

1.1

0 0.1 0.2 0.3 0.4 0.5 0.6

z/D

T/T

ad

b

numericaldata eps1(T)out BB local T

experimentaldata

numericaldata out BBlocal T

numericaldata eps2(T)out BB local T


Radiation: Effect of the dependence of Ceramic Emittance on Temperature

0.74

0.76

0.78

0.8

0.82

0.84

0.86

0.88

0 0.5 1 1.5 2

x/D

T/T

ad

b

numericalresults out BB800K

experimentalresults

numericalresults out BBlocal T

numericalresults eps1(T)out BB local T

numericalresults eps2(T)out BB local T

Lesson Learned

• Small Effect on the Dependence of Ceramic Emittance on Temperature• No Effect on Near Flame Temperature Profile• Opposite Trend are Found Depending on the Choice of Dependency Law


PE324Daniele Panara

0.76

0.78

0.8

0.82

0.84

0.86

0.88

0 0.5 1 1.5 2

x/D

T/T

ad

b

numerical resultsk-omega eps2(T)out BB localT

experimentalresults

numerical resultsk-omega ssteps2(T) out BBlocal T

numerical resultsk-eps eps2(T) outBB local T


Radiation: Effect of the Turbulence Modeling (Coarse Grid)

0.5

0.6

0.7

0.8

0.9

1

1.1

0 0.1 0.2 0.3 0.4 0.5 0.6

z/D

T/T

ad

b

numerical datak-omegaeps2(T) out BBlocal T

experimentaldata

numerical datak-omega ssteps2(T) out BBlocal T

numerical datak-eps eps2(T)out BB local T

Lesson Learned

• Small Differences Depending on The Choices of Turbulence Modelling• Best Results seem to be obtained using k- SST

Open Questions

• What is the effect of near wall grid refinement?


PE324Daniele Panara

Diagonal Swirler Simulation


PE324Daniele Panara

New Grid

• Improved Boundary Layer Resolution

• For Low Reynolds Number Turbulence Modeling

• Four Wall CJHT

• Extended Outlet Section

• New Diagonal Swirler

Inlet Conditions


PE324Daniele Panara

Results

Effect of New Geometry + Diagonal Swirler Inlet BCWith Radiation

0.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1

-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8

Z/D

T/Ta

db

steady Rad k-omega ssteps2(T) OldModelsteady RadNew Diag

experimental

0.7

0.75

0.8

0.85

0.9

0 0.5 1 1.5 2

X/D

T/T

adb

experimental results

steady k-omega ssteps2(T) outBB local TOld Model

steady RadNew Diag


PE324Daniele Panara

Effect of New Geometry + Diagonal Swirler + Radiation

Effect of Errors

in Thermocouples Positioning

0.7

0.75

0.8

0.85

0.9

0 0.5 1 1.5 2

X/D

T/T

ad

b

z=z_w bb local T

z=z_w+0.1mm bb local T

z=z_w+0.2mm bb local T

experimental

Numerical Results k-omega sst eps2(T) out BBlocal T

Numerical Results k-omega sst eps2(T) out BBlocal T z=z_w+0.1

Numerical Results k-omega sst eps2(T) out BBlocal T z=z_w+0.2


PE324Daniele Panara

Unsteady Computation

•20Hz ‘Small’ Oscillations•Unsteady effects confined in corner regions


PE324Daniele Panara



PE324Daniele Panara


• Radiation• Non Reflecting BC• displacement error:

• +0.1mm

Ceramic Wall Temperature

0.65

0.7

0.75

0.8

0.85

0.9

0 0.5 1 1.5 2

x/D

T/T

adb

t=0.18t=0.2t=0.22t=0.24t=0.26t=0.28t=0.3t=0.31999experimentalaveragedold numerical


PE324Daniele Panara

• Radiation• Non Reflecting BC• displacement error:

• +0.2mm

Ceramic Wall Temperature


0.65

0.7

0.75

0.8

0.85

0.9

0 0.5 1 1.5 2

x/D

T/T

adb

t=0.18t=0.2t=0.22t=0.24t=0.26t=0.28t=0.3t=0.31999experimentalaverageold numerical


PE324Daniele Panara

• Radiation• Non Reflecting BC

Near Flame Temperature Profile

0.4

0.5

0.6

0.7

0.8

0.9

1

-0.6 -0.4 -0.2 0 0.2 0.4 0.6

z/D

T/T

adb

t=0.18

t=0.2

t=0.22

t=0.24

t=0.26

t=0.28

t=0.3

t=0.31999

experimental data

old numerical



PE324Daniele Panara

Conclusions

• MC Fellow Activity during the Fluistcom Exchange Program in Siemens-Muelheim

Transfer of Knowledge Between Academia and Industry

• Considering a wall probe displacement error of +0.2mm good agreement between numerical and experimental results has been found.

• An improvement of the numerical results in the near flame region has been obtained

• Some unsteady flow effects have been found but seem to little affect the wall temperature and flame temperature profile


PE324Daniele Panara

Questions

Documents

Copyright © Siemens AG 2007. All rights reserved. Fluistcom Project Meeting Belfast 24th of December FLUISTCOM Exchange Program at SIEMENS-Muelheim Daniele