development of the dln micro-mix hydrogen … · development of the dln micro-mix hydrogen...
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STAR GLOBAL CONFERENCE
17 March 2015, San Diego (USA)
Development of the DLN Micro-mix Hydrogen
Combustion Technology with STAR-CCM+®
A. Haj Ayed, H.H.-W. Funke, A. Horikawa
Anis Haj Ayed
B&B-AGEMA GmbH, Aachen, Germany
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Contents
Background: Hydrogen Combustion
Micromix Combustion Technology
Experimental & Numerical Characterization
Micromix Design Exploration with STAR-CCM+
Summary
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Background
Background
Use of Hydrogen back in discussion, especially as one alternative for
energy storage
Storage of electricity surplus from renewable sources: Hydrogen
production and re-electrification by fueling stationary gas turbines.
Challenge
Premixing not feasible due to high flammability and flash back risk
High reaction temperatures lead to high NOx emissions
Solution Approach
Development of the Micromix Combustion Technology
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Micromix Hydrogen Combustion Technology
standard one
large flame
several
miniaturized
flamelets
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Micromix Hydrogen Combustion Technology
air
fuel
fuel
fuel
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0
2
4
6
8
10
12
14
16
18
0,20 0,30 0,40 0,50 0,60
NO
x@
15
% O
2 [
pp
m]
Equivalence Ratio a [-]
exp.: APU H2 030 ED 6.7
Experimental Characterization
Full Load Design Point
≈ 1.3 ppmv
distinct micromix flamelets
Electric Heater
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Micromix Hydrogen Combustion Technology
Development and Manufacturing of DLE Hydrogen Combustor based on the
Micromix burning principle:
micromix flamelets
air flow
Systematic optimization of Hydrogen Micromix burner technology based on Numerical
and Experimental investigations
Integration of optimized Hydrogen burner technology into Gas Turbine applications
Low NOx Hydrogen Combustion ! but, low energy density, large number of
injectors, high manufacturing cost!
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Burner Scaling Strategy
D
injector diameterrel. energy
density / injector
D = 0.30 mm 100 %
D = 0.45 mm 225 %
D = 0.55 mm 336 %
D = 0.84 mm 784 %
D = 1.00 mm 1111 %
reference injector size of 0.3 mm increased
gradually to decrease /minimize number of
injectors
gas turbine combustor with
several hundred Hydrogen
injectors
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air inlet
region
Hydrogen
inlet
Hydrogen
injector
AGP gateunstructured mesh, polyhedral cell
type
approx. 1mio volume cells
Numerical Approach – Calculation Domain
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Operational Conditions:
Inlet Temperatures T3: Air: 550 K
Hydrogen: 300 K
Operation Pressure p3: atmospheric (1 bar)
Numerical Methods: STAR-CCM+
- 3D steady RANS
- k,ε turbulence model
- all y+ wall treatment
Combustion Model: - EDC with DARS-CFD
Emission Model: extended Zeldovich NO formation mechanism
Numerical Models and Boundary Conditions
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Micromix Flow Field Characterization
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Micromix flamelets stabilized at shear
layer between stabilization vortices
Typical Micromix flame shape confirmed
by numerical simulation in STAR-CCM+
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cold air dilution
lateral cold air penetration
higher vortex temperature
no NO formation inside vortex
NO formation inside vortex
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Improvement of 0.3 mm Reference Burner
control of air flow around flame possible
by adjusting air gate width “A”
NOx reduction for higher equivalence
ratios
AB C
D
E
0.3 mm
0.3 mm improved
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Config. A Config. B
axial section
position
adjacent
flames
cold air
penetration
0.45 mm
0.55 mm
0.45 mm 0.55 mm
vortex cooling
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Scaling to 0.45 mm and 0.55 mm Injectors
control of air flow around flame and vortex
temperature possible
by adjusting injector distance “E”
Further scaling possible / low NOx maintained
AB C
D
E
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Scaling to 0.84 mm and Further Parametric Improvement
0.3 mm
0.84 mm
0.84 mm
improvedαD
αC > αD
dilution of hot gasH h
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0.3 mm
0.84 mm
0.84 mm
improved
locally increased NO concentration
decreased NO
concentration
Scaling to 0.84 mm and Further Parametric Improvement
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S1 S2 S3 S4 S5 S6 S7 S8axial sections: S9 S10
Scaling to 1 mm Injector Diameter
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0
5
10
15
20
25
0.15 0.25 0.35 0.45 0.55 0.65
NO
/ N
Ox
@ 1
5%
O2
[pp
m]
Equivalence Ratio ФA [-]
0.3 mm - reference
Simulation - 1.0 mm
Experiment - 1.0 mm
0
5
10
15
20
25
0.15 0.25 0.35 0.45 0.55 0.65
NO
/ N
Ox
@ 1
5%
O2
[pp
m]
Equivalence Ratio ФA [-]
Scaled --> 0.55 mm
Scaled --> 1.0 mm
0
5
10
15
20
25
0.15 0.25 0.35 0.45 0.55 0.65
NO
/ N
Ox
@ 1
5%
O2
[pp
m]
Equivalence Ratio ФA [-]
0.3 mm - improved
Scaled --> 0.45 mm
scaled --> 0.55 mm
0
5
10
15
20
25
0.15 0.25 0.35 0.45 0.55 0.65
NO
/ N
Ox
@ 1
5%
O2
[pp
m]
Equivalence Ratio ФA [-]
0.3 mm - reference
0.3 mm - improved
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reference burner improvement up-scaling and injector distance improvement
up-scaling and burner height improvement reference vs. status
15 ppm limit
NOx Emissions of Reference and Scaled Burners
6.2 to 1.1 ppm
(nearly 5 times less)
6.2 to 1.6 ppm @
11 times higher
energy density
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Summary
Successful development of Hydrogen DLN Burner with single digit NOx
emission
Numerical design exploration in STAR-CCM+ helped identify how to
control NOx emissions while increasing energy density
Injector number reduced more than 10 times while maintaining low NOx
Possible application in industrial gas turbines
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