aerosol sampling issues and system design...apex workshop cleveland, ohio bruce anderson, nasa larc...
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November 8-10, 2004 - 1 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Aerosol Sampling Issues and System Design
Bruce Anderson NASA Langley Research Center, Hampton, VA
November 8-10, 2004 - 2 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
• Characterize particle size, number, mass and composition as a function of engine power
• Examine spatial variation of across exhaust plane
• Monitor changes in particle concentrations and properties as plume dilutes and cools
• Evaluate new instruments and sampling techniques
APEX Particle Measurement Objectives
November 8-10, 2004 - 3 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Processes Influencing Particle Size and Concentration
INSTRUMENTS
ENGINE
Inertial Effects
Loss in Bends
Thermophoretic Effects
Turbulent Deposition
Gravitational Settling
Coagulation
November 8-10, 2004 - 4 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
10 1001E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
0.1
1
10
Nf/No=0.28
15 m pipe @ 10 LPM
Coagulation for EI=5e15/kg
2 Seconds Later
Initial
dN/d
Log(
Dp)
Diameter (nm)
Sampling System Design Challenges
November 8-10, 2004 - 5 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
10 100 1000
1
10Velocity Ratios (m/s) Exhaust/Inlet
Effects of Non-isokinetic Sampling
50/150
300/150
300/100
300/30300/10
Frac
tiona
l Pen
etra
tion
Diameter (nm)
Sampling System Design Challenges
November 8-10, 2004 - 6 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Relative Humidity of Sample100 % Power Setting
4:1
290 295 300 305 3100
80
160
240
Rel
ativ
e H
umid
ity (%
)
285
No Dilution
8:1
2:1
Sample Temperature (K)
Sampling System Design Challenges
November 8-10, 2004 - 7 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
• Perform dilutions close to inlet tip
• Draw samples isokinetically if possible
• Include multiple inlet tips at 1 m to allow exhaust profiling
• Include secondary inlets at 10 and 30 m to facilitate aging study
• Include automated valving system to speed up sample selection
• Provide 50 LPM total flow with low pressure drop across system
• Minimize bends, connections, line lengths, and sample residence times
Sampling System Design Criteria
November 8-10, 2004 - 8 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
DC-8
APEX Experimental Setup
10 m RAKE
1 m RAKE
30m PROBE
UMR 1
EPA
ARI
3
2 lines,one dedicated to EPA unheated, no dilution
1 m Rake, 6 ports 10 m Rake, 6 ports 30m Probe, 1 port
EPA Trailer will housed LaRC equip. and valving system
3/4”
3/8”
AEDC
November 8-10, 2004 - 9 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
EPA Trailer
0.29”x 1.8 m
1.9” x 29.3 m
Valve Box
10 m Rake 0.19”x 1.5 m
0.29”x 1.8 m
1 m Rake 0.19”x 1.5 m
Valve Box
0.62”x 23.8 m
0.62”x 20.7 m
30 m probe
APEX Aerosol Sampling System
November 8-10, 2004 - 10 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
APEX Aerosol Sampling System
November 8-10, 2004 - 11 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
APEX 1 m Sampling Rake
November 8-10, 2004 - 12 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
AEDC Aerosol Sample Inlet
November 8-10, 2004 - 13 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Converging Manifold
HEPA
6 – Port Sample Rake
Dilution Gas (Dry N2)
3/8 “ S.S. Tubing
3/8 “ Solenoid Valves
Zero Gas Line
Aerosol Sample To EPA Trailer
3/4” S.S. Tubing
1/4” S.S. Tubing 3/8” S.S. Tubing 1/4” to 3/8
Dilution Lines
3/8” I.D. Ball Valves Pneumatically Actuated
1 and 10 m Aerosol Rake Systems
November 8-10, 2004 - 14 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Aerosol Sample Valve Boxes
November 8-10, 2004 - 15 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Aerosol Sample Distribution System
November 8-10, 2004 - 16 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Sampling Flow Parameters 1m Probe 10 m Probe 30 m ProbeSystem vol rate velocity Reynolds res time res time res timeElement (lpm) (m/s) Number (s) (s) (s)
0.25" tube 50 42 35,000 0.04 0.040.375" tube 50 19 24,000 0.09 0.09 0.16
0.5" tube 50 9.8 17,000 0.22 0.22 0.050.75" tube 50 4.1 11,000 5.80 5.051.8" tube 1152 11.7 34,000 2.50
Totals 6.2 5.4 2.7
Sample System Flow Characteristics
November 8-10, 2004 - 17 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
10 100 1000
0.0
0.2
0.4
0.6
0.8
1.0
30 Probe
1 and 10 m Rakes
Diffusional and Inertial Particle Losses
Frac
tiona
l Pen
etra
tion
Particle Diameter (nm)
Sample System Flow Characteristics
November 8-10, 2004 - 18 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
-5 0 5 10 15 20 25 30 350.00E+000
1.00E+014
2.00E+014
3.00E+014
4.00E+014
5.00E+014
65%
85%
100%
Baseline Fuel
Nonv
olat
ile C
N EI
(#/k
g)
Sampling Distance (m)
Relative Sampling Efficiency of Inlets
November 8-10, 2004 - 19 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
0 5 10 15 20 25 30
1.00E+014
2.00E+014
3.00E+014
4.00E+014
5.00E+014
65%
85%
100%
Hi Sulfur Fuel
Nonv
olat
ile C
N EI
(#/k
g)
Sampling Distance (m)
Relative Sampling Efficiency of Inlets
November 8-10, 2004 - 20 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Impact of Dilution on EI
Engine Power
Sample CO23200 ppm1600 ppm800 ppm
50 60 70 80 90 1000
5
10
15
20
25(X 1.E15)
Impact of Dilution upon Aerosol Samples
November 8-10, 2004 - 21 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
0 20 40 60 80 100
0
5
10
15
20
25
30
35
40
45
50
DC-8 Plume Dilution
10 meters
30 meters
Di
lutio
n Ra
tio
Engine Power (%)
Impact of Dilution upon Aerosol Samples
November 8-10, 2004 - 22 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
0 20 40 60 80 100
10
100Aerosol Sample Dilution at 1 m
Di
lutio
n Ra
tio
Engine Power (%)
Impact of Dilution upon Aerosol Samples
November 8-10, 2004 - 23 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
0 10 20 30 40 50 60 70 80
1E14
1E1540% Power, 1 m Rake
Total
Nonvolatile
CN
Em
issio
n In
dex
(#/k
g)
Dilution Ratio
Impact of Dilution upon Aerosol Samples
November 8-10, 2004 - 24 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
0 10 20 30 40 50
1E14
1E15
40% Power, 1 m Rake
Total
Nonvolatile
CN
Em
issio
n In
dex
(#/k
g)
Dilution Ratio
Impact of Dilution upon Aerosol Samples
November 8-10, 2004 - 25 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.56.00E+013
8.00E+013
1.00E+014
1.20E+014
1.40E+014
1.60E+01440% Power, 10 m Rake
Total
Nonvolatile
CN
Em
issio
n In
dex
(#/k
g)
Dilution Ratio
Impact of Dilution upon Aerosol Samples
November 8-10, 2004 - 26 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
0 20 40 60 80 100
1E14
1E15
1 m Aerosol Probe
Hi Aromatic Fuel
CFM-56 Emissions
1 m Gas Probe
Parti
cle E
I (#/
kg)
Engine Power (%)
Impact of Inlet Probe upon Sample Integrity
November 8-10, 2004 - 27 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
0 20 40 60 80 100
1
10
100
1 m Gas Rake
1 m Aerosol Rake
Hi Aromatic Fuel
CFM-56 Emissions
1 m
Blac
k Ca
rbon
EI (
mg/
kg)
Engine Power (%)
Impact of Inlet Probe upon Sample Integrity
November 8-10, 2004 - 28 APEX Workshop Cleveland, Ohio Bruce Anderson, NASA LaRC
Summary
• Multi-port aerosol sampling system was designed, built, and successfully deployed during APEX
• Experiments suggests that sample dilutions were adequate to prevent both coagulation losses and formation of new particles within sample lines
• Comparison of data from 1 and 10 m probes indicate that thermophoretic and inertial losses are not a significant problem
• Comparison of data from “aerosol” and “gas” sample inlets suggest that standard gas sampling tips/lines perturb aerosol samples, reducing both numbers and mass