"Low NOx Flameless Combustion
for Jet Engines and Gas turbines"
Yeshayahou Levy
Technion - ISRAEL
http://jet-engine-lab.technion.ac.il
MY THANKS TO ALL CONTRIBUTORS:
•Dr. Valery Sherbaum, Technion
•Dr. Vitali Ovcherenko, Technion
•Dr. Vladimir Erenburg, Technion
•Dr. Igor Geisinski, Technion
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
9th
•Mr. Josef Shemenson , Technion
•Dr. Arvind Rao, Delft, The Netherlands
•Prof. Mario Costa, IST, Portugal
•Prof. Farid C. Christo, The University of South, Australia
Israeli Symposium on Jet Engines and Gas Turbines
October 7 2010, Technion, Istarel
1
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
100
90
80
70
2025
60
2015
50
present
40
30
20
present
10
2015
0
Noise (dB)


9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
2025
Nox, CO, UHC
(%)
Fuel
Consumption
(%)
Maintanance
Cost (%)
NOx, CO & UHC emissions are to be reduced by 70% by year
2015 and 80% by year 2025
Fuel Consumption & CO2 emission to be cut by 15% by year 2015
and 25% by year 2025
Anticipated Future Projections of
Engine performance
Turbo and Jet
Engine Laboratory
Technion – Israel
2
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NOx Formation in Combustor
• Conventional combustion process
– Primary zone (2500K)
– Dilution zone (TET=1600K)
• Formation (simplified) pathways:
– Thermal (>1800K)
O2 <=> 2O
N2 + O <=-> NO + N
N + O2 <=> NO + O
– Prompt (CH, HCN,..)
– Fuel-nitrogen (bound N)
NOx FORMATION REGION
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
CONVENTIONAL COMBUSTOR
Technion – Israel
3
www. jet-engine-lab.technion.ac.il
2200° C
T
conventional
1500° C
flameless
1300° C
400° C
No NOx
production
X
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
THE CONCEPT OF FLAMELESS GAS TURBINE
COMBUSTOR
4
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
FLAMELESS OXIDATION METHOD FOR NOx REDUCTION











CHARACTERISTICS
Recirculation of combustion products
at high temperature (> 1000°C)
Reduced oxygen concentration at the
reactance
Highly transparent flame with low
acoustic oscillation
Distributed combustion zone
Uniform temperature distribution
Reduced temperature peaks
Low adiabatic flame temperature
High concentration of CO2 & H2O
Lower Damköhler number
Low NOx and CO emission
LARGE VOLUME
% O2
% (N2+CO2+H2O)
Different Combustion Regimes (Milani & Saponaro, “Diluted
Combustion Technologies”, IFRF Combustion Journal, 2001)
Observed
Experimental
Temperature
Distribution
Plessing et al., 1998
REGULAR
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
FLAMELESS
Turbo and Jet
Engine Laboratory
Flameless Combustion
Technion – Israel
5
www. jet-engine-lab.technion.ac.il
Conventional Combustor
Texit
Gas
 High Peak Temperature
 Thin reaction zone
 High Temperature
Gradients
 High NOx production
Air
Low NOx Combustor
 Low temperature peak
 Distributed flame
 Temperature
Uniformity
 Low NOx production
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Gas
Texit
Air
Turbo and Jet
Engine Laboratory
FLAMELESS COMBUSTION PRINCIPLE
Technion – Israel
6
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FLAMELESS OXIDATION IN FURNACES
Industrial Furnace
Inlet
Main combustion
(flameless
oxidation)
Exhaust
Heat extraction
0-5% O2
Gas Turbine
Inlet
Main
combustion
Exhaust
?
14-18% O2
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
FLAMELESS OXIDATION IN FURNACES AND
GAS TURBINE.
Turbo and Jet
Engine Laboratory
Technion – Israel
7
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CONVENTIONAL GAS TURBINE
GAS TURBINE WITH THE FLOXCOM COMBUSTOR
●4
●1
●2
●3’
●3
●5
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
IMPLEMENTATION OF FLOXCOM METHOD
IN GAS TURBINES
8
●6
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
INDICATIONS OF INCOMPLETE COMBUSTION
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
CFD SIMULATIONS
(Farid C. Christo, The University of South Australia)
Turbo and Jet
Engine Laboratory
Technion – Israel
9
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OPTIONAL AIR INLETS MODIFICATIONS
Diluting air
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
A 600 MODEL OF THE COMBUSTOR SHOWING
STIRRING AND DILUTING AIR INLET HOLES
10
Stirring air
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
SECTOR COMBUSTOR - FULLY
ASSSEMBELED
Turbo and Jet
Engine Laboratory
Technion – Israel
11
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9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
OPERATING TEST RIG AT IST, PORTUGAL
PHASE I
12
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
COMBUSTION TESTS
Technion – Israel
13
www. jet-engine-lab.technion.ac.il
A22SHI
2 -2
k (m s )
72
66
60
54
A23SHI
48
Ø4
42
Ø4
36
A21SHI
30
24
18
A24SHI
12
6
0
PRIMARY ZONE
10 m/s
MEASUREMENTS AT SYMMETRY PLANE INSIDE THE COMBUSTION CHAMBER
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
MEAN VELOCITY VECTORS AND TURBULENT
KINETIC ENERGY FIELDS AT THE
14
Turbo and Jet
Engine Laboratory
Technion – Israel
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MEASUREMENTS
PERFORMED AT
THE SYMMETRY
PLANE
(IST PORTUGAL)
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
CONTOURS OF TEMPERATURE AND O2,
CO, NOX, HC, AND CO2 CONCENTRATIONS
Turbo and Jet
Engine Laboratory
Technion – Israel
15
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9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
HIGH PRESSURE FLOXCOM TEST RIG AT
ANSALDO BARI
Turbo and Jet
Engine Laboratory
Technion – Israel
16
www. jet-engine-lab.technion.ac.il
ppm
2000
ppm
20
18
1800
NOx
16
1600
NO
14
1400
12
1200
10
1000
CO
8
800
6
600
4
400
2
200
0
2.5
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
2.7
2.9
3.1
3.3

3.5
3.7
3.9
EMISSION TEST DIAGRAM AT 2.5 BARS (abs.),
NO AND NO2 Vs. THE EXCESS AIR PARAMETER
17
0
4.1
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
20.0
100
17.5
99
15.0
12.5
10.0
Config. A:
Config. B:
Config. C:
Config. D:
;
;
;
;
NOx
NOx
NOx
NOx
COMBUSTION EFFICIENCY
98
97
96
7.5
95
NOx
5.0
94
2.5
93
0.0
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
Combustion efficiency (% )
NOx (dry volume ppm @ 15% O 2)
PRELIMINARY DESIGN MODIFICATIONS
92
0.65
g
Air inlet (total = 14 holes × 2 sections)
Config.
Left inlet
Right inlet
A
oooooooooooooo
oooooooooooooo
B
o●o●o●o●o●o●o●
o●o●o●o●o●o●o●
C
oooooooooooooo
●●●●●●●●●●●●●●
D
o●o●o●o●o●o●o●
●●●●●●●●●●●●●●
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
EFFECT OF GEOMETRICAL
VARIATIONS
P=1 bar (abs)
Q= 4KW
(24 KW complete section)
Turbo and Jet
Engine Laboratory
Technion – Israel
18
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P=1 bar (abs)
Q= 8KW
(48 KW complete section)
Fuel mixture
1
2
3
4
9
CH4
100
91
81.9
76
39.2
H2
0
9
18.1
24
43.3
CO2
0
0
0
0
17.5
LHV (MJ/Nm3)
35.80
33.55
31.27
29.79
18.70
Tad (ºC)
1952
1956
1961
1965
1923
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
EFFECT OF FUEL COMPOSITION
(COMBUSTION OF SYNGAS)
Turbo and Jet
Engine Laboratory
Technion – Israel
19
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•
•
•
•
FLOXCOM COMBUSTOR HAS LARGE STABLE OPERATIONAL
RANGE.
NOx EMISSION IS LOW AS EXPECTED.
CO AND UHC ARE MODERATE, DESIGN MODIFICATION IS ARE
REQUIRED
BASIC STUDY IS NEEDED TO FILL GAPS
2nd PHASE OF THE STUDY:
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
INTERMEDIATE CONCLUSION
Turbo and Jet
Engine Laboratory
Technion – Israel
20
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Conventional Flameless for Gas
Turbine
Inlet
Main
combustion
Exhaust
14-18% O2
New design for
Aero-engine
Heat extraction
Inlet
21 % O2
Exhaust
Main
combustion
ADVANTEGEOUS:
•COOLER FLAME
•NEED FOR LOWER
RECIRCULATION RATIO
5-8 % O2
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
MODIFIED FLAMELESS COMBUSTOR WITH
INTERNAL HEAT EXCHANGER.
21
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
x Junction
Primary Air
2
Main Combustion
3
Recirculation Zone
1
Pre-combustion
Inlet
Exit
5
Fuel
4
Heat exchanger
Secondary Air
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
HEAT AND FLOW DIAGRAM MODIFIED FLAMELESS COMBUSTOR.
Turbo and Jet
Engine Laboratory
Technion – Israel
22
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‫פתח הזרמת‬
‫אוויר‬
‫אזור האוויר‬
‫העוקף‬
‫פתחי הזרמת‬
‫דלק‬
‫צלעות מחליף‬
‫החום באזור‬
‫הבעירה‬
(‫דופן תא )אזור‬
‫הבעירה‬
USING OPTIMAL CONFIGURATION,
COMBUSTION TEMPERATURE MAY BE
REDUCED BY AS MUCH AS 170 °C !
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
THE HEAT TARNSFER MECHANISM
Technion – Israel
23
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SINGLE JET FLAMELESS COMBUSTOR
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
SINGLE JET STUDY
Turbo and Jet
Engine Laboratory
Technion – Israel
24
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DIFFUSION
FLAMELESS
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
Technion – Israel
25
www. jet-engine-lab.technion.ac.il
GASEOUSE
FUEL INLETS
AIR INLET
Cy
cl
e
rfac
u
ic S
CH4
MESH FOR 1/16
SECTOR
Air
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
CFD SIMULATIONS - TECHNION
COMBUSTION CHAMBER WITH 16 FUEL INLET26
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
TEMPERATURE
DISTRIBUTION
~1800K
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
TEMPERATURE DISTRIBUTION
Technion – Israel
27
www. jet-engine-lab.technion.ac.il
To outlet
CH4 inlet
Air inlet
|
0
mm
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
|
|
|
25
|
|
50
|
|
75
VELOCITY FIELD AT THE CENTER LINE
CROSS-SECTION
Turbo and Jet
Engine Laboratory
Technion – Israel
28
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RECIRCULATION REGION
To outlet
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Vz - VELOCITY COMPONENT'S DISTRIBUTION
29
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
DIFFUSION REGION
FUEL ENTRAINMENT
Preliminary NO predictions
|
|
|
|
|
|
3
6
9
12
|
0
mm
Temperature distribution
NO level
5 ppm
0
NO mass-fraction distribution
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
TEMPERATURE DISTRIBUTION –
(NEAR NOZZLE REGION)
Turbo and Jet
Engine Laboratory
Technion – Israel
30
www. jet-engine-lab.technion.ac.il
TK
experiment
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
THERE IS STILL
ROOM FOR
IMPROVEMENTS
IN THE
MODELING …
simulation
COMPARISON – CFD SIMULATIONS EXPERIMENT
Turbo and Jet
Engine Laboratory
Technion – Israel
31
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Regime
Tmax , K
Texit , K
COexit
NOexit
Krecirc.
Adiabatic
2460
1900
8.6x10-12 ≃ 0
46x10-6
1.6
Flux = -15kW/m2
2290
1760
3.3x10-12 ≃ 0
4.4x10-6
1.6
Flux = -25kW/m2
2190
1680
2.5x10-12 ≃ 0
0.76x10-6
1.6
Exp. data
-
1630
0
10x10-6
-
INCORPORATION OF
HEAT LOSS IN THE
MODELING IMPROVED
RESULTS
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
COMPARISON OF SIMULATION AND
TEST RESULTS
32
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
summary
• Basic modeling of the FLOXCOM combustion method
was complete.
• Detailed investigation into internal mixing and enhanced
wall heat transfer is currently being performed.
• CFD modeling of Jet Flame configuration coupled with
experimental result seems to present an efficient tool to
gain practical knowledge.
• Final integration stage is still needed for an engineering
flameless combustion design
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
Technion – Israel
33
www. jet-engine-lab.technion.ac.il
GE-90
 c 1


c


P
U 9'  2  n 'Cpc T07 ' 1   9'  
  P07 '  


9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
INCORPORATION OF MODIFIED COMBUSTOR
IN A TURBO-FAN ENGINE.
34
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
35
Pollutant Reduction Problem
• Compromises involved with
conventional combustors:
– Emitted species
– Flame stability
– Cycle efficiency
• Need for alternative
combustion concepts
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
LOWER STABILITY LIMIT
LOW-EMISSION WINDOW
Turbo and Jet
Engine Laboratory
Wulff and Hourmouziadis, 1997
Technion – Israel
35
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Observed Experimental
Temperature Distribution
Plessing et al., 1998
• Stable and safe
Flame
combustion
• Uniformly
distributed
temperature
• Low-NOx emission
Stability limits -SchematicAfter Wunning and Wunning, 1997
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
COMBUSTION IN HOT VITIATED AIR
Technion – Israel
36
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16
14
12
10
8
6
4
2
0
Gas
turbines
II
I
IF GASES WITH LARGE
OXYGEN CONCENTRATION
ARE RECIRCULATED,
HIGH ADIABATIC
TEMPERATURES ( AND
NOx) ARE OBTAINED
CO2 ,
H2O.
Industrial
furnaces
0
5
10
15
20
Oxygen mole fraction, %
25
I – BEFORE COMBUSTION
(STIRRING AIR),
II – AFTER COMBUSTION,
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
O2, CO2, H2O MOLE FRACTION AT THE
RECIRCULATION ZONE
Technion – Israel
37
www. jet-engine-lab.technion.ac.il
ry
da
n
co
Se
Inlet
ai r
Recirculation Zone
Se
co
nd
ar
y
Exit
Mixing Zone
Primary
air
Recirculation Zone
Fuel Inlet
ai
Mixing holes
r
Secondary Air
Exi
t
Composite
Metallic Fins
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Fuel
Inlet
SCHEMATIC REPRESENTATION OF THE FLUID
FLOW WITHIN THE “MODIFIED” COMBUSTORS
38
Turbo and Jet
Engine Laboratory
Technion – Israel
www. jet-engine-lab.technion.ac.il
GLOBAL EVALUATION OF THE FLOXCOM COMBUSTOR
Known parameters and assumptions:
•Inlet air temperature Ta
•Inlet mass flow rate ma ,
•exit temperatures Te
•100% combustion and mixing efficiency
calculated Values:
•Air flow distribution:
stirring air, mas,
dilution air, mad
stirring gas, mas+mr
•Temperature :
stirring gas, Ts
combustion, Tc
•Recirculation rate:
k
•oxygen percentage in every stage of the cycle.
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
Turbo and Jet
Engine Laboratory
Technion – Israel
39
www. jet-engine-lab.technion.ac.il
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
HIGH PRESSURE FLOXCOM TEST RIG
AT ANSALDO BARI
Turbo and Jet
Engine Laboratory
Technion – Israel
40
www. jet-engine-lab.technion.ac.il
T2
[ x3]
T3
[ x3]
T1
[ x3]
Air In
Exhaust gases
P1
[ x3]
T1...T3 - Temperature Sensores
P1 - Pressure sensores
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
CROSS SECTION OF THE 360 DEGREES
MODEL OF THE FLOXCOM COMBUSTOR.
Turbo and Jet
Engine Laboratory
Technion – Israel
41
www. jet-engine-lab.technion.ac.il
ppm NOx
200
..........…
100..............
0
................
9th Israeli Symposium on Jet
Engines and Gas Turbines,
October 7 2010,
Technion, Istarel
FLOXCOM RELATIVE
PERFORMANCE
Turbo and Jet
Engine Laboratory
Technion – Israel
42
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