Alternative fuel test on PW308 engine - NASA · Primary test objective: determine the impact of...
Transcript of Alternative fuel test on PW308 engine - NASA · Primary test objective: determine the impact of...
Alternative fuel test on PW308 engine
A Collaborative effortNASA, AFRL, ARI, UTRC and P&W
Anuj Bhargava
AerodyneResearch, Inc.
2
Tests performed to investigate impact of alternative fuels
Primary test objective: determine the impact of synthetic fuel on performance and emissionsSecondary test objective
Impact of heated fuel on emissions and performanceSpatial differences in emissions
Measurements performed on PW 308 engineSampling rake with multiple gas and particle probe used to collect sample at engine exhaust and at 50mMeasurement team
NASA: PM and Gaseous emissionsAFRL: PM and Gaseous emissionsARI: Volatile PM emissionsUTRC: Sampling SystemP&W: Performance and test lead
All test objectives achieved
Successful testing of all three fuels (JP8, Synthetic fuel or Fischer Tropsch (FT) fuel, and Blend)
No significant difference in engine performance or gaseous emissions with the three fuelsPM emission reduction with blend and synthetic fuelHeated fuel had higher NOx emissions
Excellent set of data to validate models
4
Agenda
Tests conductedResults
Engine performance and gaseous emissions with the different fuelsDifference in non-volatile PM emissions Volatile PM emissions
5
Agenda
Tests conductedFuels testedSampling systemTest matrix
ResultsEngine performance and gaseous emissions with the different fuelsDifference in non-volatile PM emissions Volatile PM emissions
6
Test setup
7
Composition of synthetic fuel looks different from JP8
5 10 15 20 25 30Time-->
C11
C12
C10C9
C8 5172 F-T Kerosene
Con
cent
ratio
n
5 10 15 20 25 300
C11C12
C13
C14
C15
C16
C17C18
C10
C9
C8
C7
C19
JP-8
8
The three fuels have similar properties
Property JP-8 Blend SyntheticViscosity (cSt) 1.38 1.14 0.96
Specific Gravity 0.8050 0.7734 0.7377Net Heat of Combustion
(Btu/lb) 18,533 18,735 18,960Hydrogen % mass 13.95 14.78 15.71
Particulate contamination (mg/L) 0.71 0.21 0.11Sulphur content (%) 0.123 0.065 0.003
Aromatic content (%) 19 10.1 0.17
Properties of the blend are within the Aviation fuel SpecsSynthetic fuel doesn’t meet Aviation fuel spec
9
Control
Room
Cooling H2 O
Power
208 Single
Phase, 250 A
PW
308
GN2 - Stand
Air - Stand
Gas lines
Rake
Elevated Test Stand
Aerosol lines
50 m Probe
Communication lines
Valve Boxes
AFRL Trailer
NASA (+ARI) Trailer
Test Setup
10
Particle Probe Plumbing designed to minimize particle losses
AFRL
NASA
50 M Probe Vacuum
Pump
MANIFOLD
1” Conduit, 130’
3/4” PTFE, 20’
MFC Dry N2
0 – 100 LPM
FILTER
3/8” PTFE, 10’
3/8” PVC
DILUTION GAS
Valve Box
ARI
3/4” PTFE, 20’
Considerable effort expensed to insure that the sampling methodology follows the recent advancement made in PM emission measurement
Probes
11
Pretest Line Loss Prediction for 50 m probe
Pretest Line Loss Prediction for 1 m probe to NASA instruments
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
10 100 1000
Particle Diameter (nm)
1M-NASA+AFRL
Pretest Line Loss Prediction for 1 m probe to AFRL instruments
Line loss estimation model predicts line losses within acceptable limits
Acceptable limit
12
Full suite of Aerosol Instruments used to characterize emissions
MAAP
LiCor 6251
3022 CPC
EEPS
Sample Manifold
EC/OC Filter
50 m1 m
AFRL
CPC, SMPS,
TEOM, EC/OC,
Smoke, PAH
P, T, RH
UHSAS SMPS w/3010
Aerodyne AMS
heaterSMPS w/3776
3775 CPC
OVERALL• 6 number densities• 5 size distributions• 4 Mass• 1 Composition
13
1 m Sampling Rake Setup
11
10
9
8
6
5
4
3
2
1
7
Blank
Top
Particle Probe
Particle Probe
Particle Probe
Particle Probe
Particle Probe
Gas Probe
Particle Probe
Gas Probe
Gas Probe
Blank
Engine Center Line
Each probe tip separated by 1.25”
0
2
4
6
8
10
Probe 8
Probe 4
Probe 2
Probe 3
Probe 7
Probe 6
Probe 5
Probe 9
Probe 10
14
heated fuel
heated fuel
PW308 Emissions Test Matrix designed to fulfill all objectives
DAY 1DAY 2DAY 3
Elapsed Time (hh:mm)00:00 01:00 02:00 03:00 04:00 05:00 06:00
Engine Pow
er, % 0
20
40
60
80
100JP-8FT Fuel50/50
Heated fuel
Heated fuel
15
Agenda
Tests performedResults
Engine performance and gaseous emissions with the different fuels
Difference in non-volatile PM emissions Volatile PM emissions
16
Engine and emissions data does not indicate major differences between the three fuels
GASEOUS EMISSIONSAt low power
NOx emissions are within instrument measurement capabilitiesLower CO with FT/blend may be due to higher H/C ratio
At intermediate/high powerVery low CO emissions make ratios irrelevant to evaluate differences between the fuelsNo significant difference in NOx emissions
Negligible UHC at all power conditions for both fuelsSO2 emissions indicate Sulfur content of the blend to be around 50% of JP8 while for 100% FT fuel a value of 0.1% indicates contamination~2% fuel flow benefit with 100% synthetic fuel can be attributed to the higher heat content of synthetic fuel
Negligible differences in gaseous emissions & performance as expected due to similarity in the physical properties of the fuels (like heating value, specific gravity)
Fuel flow NOx COLOW (2200) 0.95
INTERMEDIATE (4500) 0.98HIGH (5750) 1.0
0.97NANA
Thrust (Rotor Speed N1)
RATIO -
Blend/JP8
0.9991.000.995
SO2
0.500.540.54
Fuel flow NOx CO0.90
0.970.98
0.97NANA
RATIO –
FT100%/JP8
0.9850.9820.978
SO2
0.050.10.1
17
Agenda
Tests performedResults
Engine performance and gaseous emissions with the different fuelsDifference in non-volatile PM emissions
For the different fuels (JP8/Synthetic/blend)
Volatile PM emissions
18
‐34%
‐29%
‐19% ‐18%
‐41%‐43%
‐26%
‐19%
‐3%
‐92%
‐76%
‐50%
‐45%
‐31%
‐91%
‐77%
‐55%
‐45%
‐36%
‐100%
‐80%
‐60%
‐40%
‐20%
0%
Idle 30% 65% 75% 85%
Percen
t Change in PN EI Relative to JP
‐8
Engine Setting
FT blend AFRL
FT blend NASA
FT AFRL
FT NASA
Synthetic fuel reduces Particle Number Emission Index
As expected lower PM emissions with synthetic fuel due to its chemical composition (higher H/C ratio and no aromatics/Sulfur)
19
‐16%
‐29% ‐28%
‐22%
‐28%
‐18%
‐13%
0%
‐80%
‐71%
‐65%
‐57%
‐91%
‐72%
‐46%
‐35%
‐28%
‐100%
‐80%
‐60%
‐40%
‐20%
0%
Idle 30% 65% 75% 85%
Percen
t Change in PM M
ass EI Relative to JP
‐8
Engine Setting
FT blend AFRL
FT blend NASA
FT AFRL
FT NASA
Particle Mass Emission Indexgoes down with synthetic fuel
As expected PM emission reductions not proportional to the fraction of FT fuel Greater discrepancy in the measurements between the different teams
20
As expected greater SN changes with 100% Synthetic fuelthan with the blend
‐18%
‐5%‐7%
‐11%
‐44%
‐39%‐41%
‐44%
‐50%
‐45%
‐40%
‐35%
‐30%
‐25%
‐20%
‐15%
‐10%
‐5%
0%
30% 65% 75% 85%
% Cha
nge Re
lative
to JP
‐8 Smoke Num
ber
Engine Setting
FT Blend
FT
21
0 20 40 60 800.0
0.2
0.4
0.6
0.8
1.0
Nor
mal
ized
Num
ber E
I
Power (%)
FT
50:50 blend
"Cold" TSI3775
FT produces >90% reduction at idle, 40% at high power
Measurement uncertainty is lower than PM EI reduction with synthetic fuel
0 20 40 60 80 1000.0
0.2
0.4
0.6
0.8
1.0
Nor
mal
ized
Mas
s E
IPower (%)
FT
50:50 blend
MAAP
22
Particle size distribution for the different fuels at different powers show similar trends
FT fuel makes lower number of particle emissions as well as particle of smaller size
0E+0
1E+6
2E+6
3E+6
4E+6
5E+6
0 20 40 60 80 100 120 140 160Particle diameter, nm
Num
ber c
ount
JP8 - Idle SYN - Idle
JP8 - 30% SYN - 30%
JP8 - 75% SYN - 75%
23
FT fuels provide larger percentage reductions at lower power conditions
FT emissions are small, more difficult to discriminate from background at
lower thrust conditions
Differences at higher thrust conditions are less
0E+0
1E+6
2E+6
3E+6
4E+6
5E+6
0 50 100 150 200Particle diameter, nm
Num
ber c
ount
JP8Blend100% Synthetic
0E+0
1E+6
2E+6
3E+6
4E+6
5E+6
0 50 100 150 200Particle diameter, nm
Num
ber
coun
t
JP8Blend100% Synthetic
(both figures drawn to same scale)
24
Particle mean diameter decreases with increase in FT fuel content
Particle mean diameter along with particle number count decreases from JP8 to Blend to FT fuel
Idle 30% 65% H 65% 75% 85% H 85%Particle M
ean Diameter (n
m)
Engine Setting
Particle Mean Diameter
JP‐8
Blend
FT
Mass variability for synthetic fuel for the different instruments not well understood
Mass EI estimated or measured with different instrumentsEEPS and SMPS measure size distribution and numbers. Mass estimated using volume of particles and density
MAAP and UHSAS measure mass more directly (based on reflectivityindex)
Estimations based on the assumption that all particles generated by the different fuels have same physical/chemical properties
The differences in the observed mass may be due to Particles generated with the different fuels may have different physical or chemical properties
The different instruments have different cut-off size ranges
26
0 20 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
Nor
mal
ized
"Mas
s" E
I
Power (%)
MAAPUHSAS
EEPS
Reduction in Mass EI much more sensitive and variable for the
different instruments
Reduction in number EI very similar for the different instruments
Mass EI data for 100% synthetic fuel sensitive to instrument selection
0 20 40 60 80 1000.0
0.2
0.4
0.6
0.8
1.0
SMPS
Nor
mal
ized
Num
ber E
I
Power (%)
EEPS
CPC 1
CPC
27
Number EIs variability probably because of variations
in instrument sensitivity
Ratio of “Mass” EIs quite variable at low power,
background particles may be a contributing factor
Blend data shows more variability at low thrust while high thrust data similar to FT fuel
0 20 40 60 800.0
0.2
0.4
0.6
0.8
1.0
Nor
mal
ized
"Mas
s" E
I
Power (%)
SMPS
MAAPUHSAS
EEPS
0 20 40 60 800.0
0.2
0.4
0.6
0.8
1.0
CPC
Nor
mal
ized
Num
ber E
I
Power (%)
EEPSCPC
SMPS
28
Measuring PM emissions at 50m is difficult
Wind causes plume to waver back and forth
across 50 m inlet probe
CO2 @ CN Counts
50 mProbe
29
Comparison between 1m and 50 m data reveals useful information on PM formation
FT fuel produced significantly lower volatile PM emissions at 1m and 50m
0 20 40 60 80 100
0
10
20
30
40
50
Nor
mal
ized
Num
ber E
I
Power (%)
FT50/FT1
Emissions at 50 meters"Cold" TSI3775
J50/FT50
J50/J1
J1/FT1
30
Agenda
Tests performedResults
Engine performance with the different fuelsDifference in non-volatile PM and gaseous emissions
Between hot and cold fuel
Volatile PM emissions
31
Heated fuel (600 F) gives slightly better SFC
0.96
0.965
0.97
0.975
0.98
0.985
0.99
0.995
1
1.005
FNR2 WFR2 TSFC
Performance property
Rat
io h
eate
d/un
heat
ed
JP8-65% JP8-85%Synthetic-65% Synthetic-85%Blend-65% Blend-85%
Heated fuel led to higher combustor inlet temperature and hence improved SFC by 0.5-1%
32
Heated fuel produced more NOx and slightly higher SN
SN differences between the heated fuel and cold fuel was on the order of +10% which is within measurement uncertaintyNOx for heated fuel was ~15% higher for heated fuel
Combustor (nozzles) are not optimized for heated fuelHigher stoichiometric flame temperature with heated fuel
33
Differences between heated and unheated fuels within experimental uncertainty
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
coldCN hotCN EEPS coldSMPS hotSMPS
Instrument : Number
ratio
: hea
ted/
unhe
ated
JP8 65%JP8 85%Synthetic 65%Synthetic 85%Blend 65%
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
EEPS-m coldSMPS hotSMPS UHSAS-m MAAP-m SN
Instrument : Mass
ratio
: hea
ted/
unhe
ated
JP8 65%JP8 85%Synthetic 65%Synthetic 85%Blend 65%
PM emission measurements indicate no significant difference between heated fuel and unheated fuel
34
Agenda
Tests performedResults
Engine performance with the different fuelsDifference in non-volatile PM and gaseous emissions
Spatial variation
Volatile PM emissions
35
Spatial variation in the data captures the partial mixing of core and bypass stream
Partially mixed exhaust leads to variation in actual
emissions but EI’s are consistent across the exhaust
0
5000
10000
15000
20000
25000
30000
0 2 4 6 8 10 12
Radius, inch
CO
2, pp
m
0
20
40
60
80
100
120
NO
x, pp
m
CO2NOx
0
1
2
3
4
5
6
7
8
9
10
0 2 4 6 8 10 12
Radius, inch
NO
x EI
36
Just like gaseous emissions, PM number EI indicate little spatial variation
SMPS
0 2 4 6 8 10distance from center
tip 1- 65%tip 2- 65%tip 3 - 65%tip 4 - 65%
CN counter
EEPS
CN counter
0 2 4 6 8 10distance from center
tip 1- 65%tip 2- 65%tip 3 - 65%tip 4 - 65%
EEPS
JP8 SyntheticInstrument-instrument variability much
higher then spatial variation
37
PM emissions with different instruments may not give same answers if instrument size cut-off is different
Differences in total number count between different instruments can be attributed to differences in instruments “cut-off” sizes
0 5 10 15 20
CNCSMPSCNC 1SMPS-1
RUN #TOTA
L PA
RTI
CLE
CO
UN
TS, #
1E+1
1E+3
1E+5
1E+7
1E+9
1 10 100 1000Size, nm
Num
ber o
f par
ticle
s
Two SMPS with different size cut-offs
38
• Negligible Thrust and Fuel Flow impact of FT fuel as compared to JP8
• No significant difference in Gaseous emissions for the different fuels
• PM emissions for the different fuels• Pure FT EI values are an order of magnitude lower in both number & mass at idle
relative to JP8. Differences between the fuels diminish with increasing power.
• Changes in observed Number EIs largely independent of instrument; “mass” EIs sensitive to measurement technique.
• FT particles much smaller, appear to be more dense than JP8
• Emission reductions not proportional to the fraction of FT
• FT suppresses volatile aerosol formation in plume
• At the 50 meter probe, JP8 idle Number EIs 45 times higher that FT; differences decrease with power.
Summary of Non-volatile PM
39
• Spatial variation in emissions indicates unmixedness. Constant Emission EI across the exhaust indicates all emissions vary in a similar fashion
• Useful information to determine mixer efficiency
• Heated fuel had a higher NOx EI than unheated fuel
•
Excellent set of data to model/develop combustion kinetics and impact of fuel composition, thrust (temperature/pressure) on PM emissions
•
Consistent trends with changes in fuels (JP8 vs. blend vs. 100% FT fuel) can be used to resolve the impact of fuel composition on PM emissions
•
Heated unheated fuel data can be used to model impact of temperature on gaseous as well as PM emissions
•
Data collected at different power level can be used to model impact of f/a, temperature and pressure on emissions
Summary of Non-volatile PM (cont.)
40
Agenda
Tests performedResults
Engine performance with the different fuelsDifference in non-volatile PM and gaseous emissions Volatile PM emissions
41
Exit Plane Organic, Oil & Sulfate EmissionsPM Organic PM Sulfate
EIm
-organic > EIm
-sulfate > EIm
-oil consistent with previous field measurementsVery little volatile PM emission concentration measured at engine exhaust
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
EIm
-org
anic
(mg
kg-1
)
80604020
Power %
JP-8 100% FT 50% FT
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
EI m
-SO
4 (m
g kg
-1)
80604020
Power %
JP-8 100% FT 50% FT
0.4
0.3
0.2
0.1
0.0
EIm
-oil
(mg
kg-1
)
80604020
Power %
JP-8 100% FT 50% FT
PM Oil
42
Detailed Spatial Profile of EIM -organic made at engine exhaust
-4
-3
-2
-1
0
1
2V
eriti
cal P
ositi
on (i
nche
s)
86420
Horizontal Position (inches)
JP-8 85% powerFull scale is 0.02 to 2 mg kg-1
Error bars scale with measurement uncertaintyMarker size scales with EIM-organic (ranges from 0.8 ±
0.14 to 1.3 ±
0.4 mg kg-1)
Organic EIs are relatively constant across
the engine exit plane
43
Re-scaled Profile of EIM -sulfate
JP-8 85% powerMarker size scales with EIM
-sulfate (ranges from 0.06 ±
0.01 to 0.40 ±
0.06 mg kg-1)Full scale is 0.02 to 0.2 mg kg-1
Error bars scale with measurement uncertainty
•Plot shows that entrained bypass air is the source of sulfate at 1m
•Signal too weak to generate particle size distribution with AMS
-4
-3
-2
-1
0
1
Ver
itica
l Pos
ition
(inc
hes)
86420
Horizontal Position (inches)
44
Detailed Profile of EIM -oil
JP-8 85% powerFull scale is 0.02 to 2 mg kg-1 Marker size scales with EIM
-oil (ranges from 0.036 ±
0.006 to 1.9 ±
3.3 mg kg-1)Error bars scale with measurement uncertainty
Oil EIs are consistent with an intermittent
source at the periphery
-6
-4
-2
0
2
Ver
itica
l Pos
ition
(inc
hes)
86420
Horizontal Position (inches)
45
Organic PM Emissions at 50mEIm
-
organics ≈
25 ±
10 mg kg-1
• EIorganics
only a small fraction of total PM emissions• Significant amount of lubrication oil (>75%) • EIorganics
independent of thrust condition/fuel
7
6
5
4
3
2
1
Org
anic
PM
(μg/
m3 )
4:17:45 PM3/26/2008
4:18:00 PM 4:18:15 PM 4:18:30 PM
dat
600
550
500
450
400
CO
2 (pp
m)
500x103
400
300
200
100
CPC
(cm
-3)
100% FT, 85% Thrust
Date and Time
Unusual level of lube oil may be due to test engine configuration
46
Organic at 50m is larger than soot
2 3 4 5 6 7 8 9100
2 3 4 5 6 7 8 91000
Dva (nm)
4
3
2
1
0
(dμg
/m3 /lo
gDp)
soot size range
organic PM - plume organic PM - ambient sulfate PM - ambient/plume
100% FT, 85% power
soot coating?
Similar results found at other power conditions and for other fuelsOrganics at 50m have same particle size distribution as periphery of engine exit planeOil is not
coated on the soot –
consistent with emission as liquid droplets
47
EIm
-sulfate (JP8) = 3.5 ±
1 mg kg-1
(1200 ppm sulfur)EIm
-sulfate (50% FT) = 1.5 ±
0.5 mg kg-1
(600 ppm sulfur)EIm
-sulfate (100% FT) < 0.05 mg kg-1
(30 ppm sulfur)
JP-8 – CO2 /number peaks coincide with sulfate peaks
Plumes for JP8 shows contribution of sulfate particles
3.0
2.9
2.8
2.7
2.6
2.5
AM
S S
O4
PM
(μg/
m3 )
4:45 PM3/25/2008
4:46 PM 4:47 PM 4:48 PM
dat
1.0
0.8
0.6
0.4
AM
S O
rgan
ic P
M (μ
g/m
3 )3.0
2.5
2.0
1.5
1.0
0.5
0.0
AM
S O
il PM
(μg/
m3 )
550
500
450
400
350
CO
2 (p
pm)
700x103
600
500
400
300
200
100
CP
C
0.355
0.350
0.345
0.340
0.335
0.330
0.325
NH
4/S
O4
48
PM Plumes for 100% FT fuel shows sulfate concentration less than background
100% FT – CO2 /number peaks coincide with sulfate valleys, i.e. Sulfate concentration in plume is less than ambient sulfate levels
1.90
1.85
1.80
1.75
1.70
1.65
AM
S SO
4 PM
(μg/
m3 )
3:46:00 PM3/26/2008
3:46:30 PM 3:47:00 PM 3:47:30 PM 3:48:00 PM 3:48:30 PM 3:49:00 PM
dat
2.0
1.5
1.0
0.5
AM
S O
rgan
ic P
M (μ
g/m
3 )
7
6
5
4
3
2
1
AM
S O
il PM
(μg/
m3 )
700
600
500
400
CO
2 (p
pm)
600
500
400
300
200
100
x103
49
PW308 Sulfate PM data shows that sulfate PM emissions relate directly to fuel sulfur
PW308 sulfate data follows the trend seen in previous tests
5
4
3
2
1
0
EIm
-sul
fate
(mg
kg-1
)
3.02.52.01.51.00.50.0
Fuel Sulfur Content (g kg-1)
CFM56 Engines N817NA base sulfur (-2C1) N817NA high sulfur (-2C1) N353SW (-3B1) N695SW (-3B1) N14324 (-3B1) N70330 (-3B1) N429WN (-7B22) N435WN (-7B22)
best-fit line R2 = 0.89SO2 = SO3 conversion 0.09 ± 0.1%
Other Engine Types N75853 (RB211-535E4-B) N74856 (RB211-535E4-B) N729FD (PW4158) N616NA (CJ6108A) PW308 AE3007
≥85% thrust
EIm-s
ulfa
te (m
g kg
-1)
Fuel Sulfur Content (g kg-1)
50
Preliminary Data InterpretationVolatile content of PW308 “organic particles” is lubrication oil, partially burned fuel
Lubrication oil emitted as 100-400 nm droplets in the bypass flow – EIm-oil not a strong function of power or fuel
Lubrication oil may be the dominant source of PM especially at low power conditions and especially for synthetic fuels
Partially burned fuel characteristic of hydrocarbon
At engine exit plane, partially burned fuel is coated onto soot
At 50 m, EIm-sulfate depends linearly on fuel sulfur content
At 50 m, plumes generated by FT combustion contain “less”particle sulfate than ambient air
51
WOULD LIKE TO SAY THANK YOU
TO THE WHOLE MEASUREMENT TEAM