WP-1538Development of an EPA Approved Interim Particulate Matter Test Method (IPMTM)

for the JSF High Performance Gas Turbine EnginePerformers

Research Team (*Authors)

•*Capt Charles McNiel – USAF/Arnold Engineering Development Center

•*Dr. Robert Howard – ATA/Arnold Engineering Development Center, SAE E31

•*Dr. Philip Whitefield – Missouri University of Science and Technology,

Director Center of Excellence for Aerospace Particle Emission Research, SAE E31

•*Dr. Richard Miake-Lye – Aerodyne Research, Inc. Center for Aero-

Thermodynamics, SAE E31

• Dr. Dave Gemmill (QAPP) – Quality Assurance Consulting

Stakeholder Participants• Dr. Stephen O. Andersen – US EPA, Director of Strategic Climate Projects, Office of Air and Radiation

• Mr. John Kinsey – USEPA Technical Liaison to IPMTM project, SAE E31

• Ms. Jean Hawkins – Joint Program Office, Joint Strike Fighter, Environmental, Safety and

Health Manager

• Mr. William Voorhees – Naval Air Systems Command, Director of Science and Technology,

Propulsion and Power Engineering Department

• Mr. Steven Hartle – Naval Air Systems Command, Propulsion and Power Engineering Dept.

• Mr. Triet Nguyen – Navy Aircraft Environmental Support Office (AESO), SAE E31

• Dr. Xu Li-Jones – Navy Aircraft Environmental Support Office (AESO), SAE E31

• Mr. Anuj Bhargava – Pratt & Whitney (JSF PM Measurement Requirements), SAE E31

• Mr. Dave Liscinsky – UTRC

• Dr. Chowen Wey – Army Research Lab, SAE E31

• Dr. Bruce Anderson – NASA Langley Research Center

WP-1538 Project Flow

Coordination

• EPA: Adopt the Interim PM Test measurement protocol for the JSF engine

• JPDO EIPT: To integrate with the strategic plan for the next generation air transportation system (NGATS)

• NASA and FAA: To Integrate with the milestones of the National PM Roadmap

• SAE E-31: To accelerate the science of PM testing and development of an Aerospace Recommended Practice

Technical Approach

• Measure non-volatile particles at the engine exit plane.• Measure engine exit plane precursor gases and analyze relevant fuel constituents to infer the volatile

particle component of engine emissions. • Sample using a multi-point rake containing both gas and particle sampling probes and traverse rake. • Use a gas sampling probe design typical for commercial engine certification measurements by engine

manufacturers.• Use a particle sampling probe that introduces an inert gas to the exhaust sample near the probe tip to

minimize particle loss, preserve particle sample integrity and reduce the particle concentration to acceptable analyzer limits.

IPMTM Methodology Selection

• Build on probe development under previous NASA programs (AEAP, NASA/QinetiQ, APEX-series) − These measurement studies pursued emission characteristics data− Provided extensive experience using effective probe design− Redundant measurements, identified issues for quantitative accuracy and reproducibility

• Basic science issues of probe chemistry and physics are addressed separately and in parallel under NASA and FAA sponsorship

• Conduct an engine test to resolve methodology issues identified from prior studies; sampling parameterization sensitivity, instrumentation comparisons and selection, measurement repeatability, validate sample line penetration method

• Define methodology and conduct validation/evaluation engine emissions test

F135 “Quick-Look” Test

Objective & Approach• Assessed measurement and data issues for implementation of the

IPMTM for the JSF engine• Sampled multiple exit plane spatial locations at steady-state powers

from idle to mil-power• Acquired real-time PM number and size distribution

• Missouri Univ. of Science & Technology (MST) Mobile Aerosol Sampling System (MASS)

• MST Cambustion DMS 500 Fast Particle Spectrometer• NASA TSI EEPS and conventional PM monitoring• AEDC Multi-Gas Analyzer (MGA) for real-time gaseous emissions

and partial HC speciation

Results• PM size distributions were consistent with other military engine

measurements• PM number was consistent with low Smoke Number, consistent or

lower than measured emissions of other military engines, and significantly less than commercial engines

Engine

Methodology Test (April 2007)

Objective: Methodology Issues Resolution• Demo of in-the-field method for sample train penetration measurement

• Demo of in-the-field method for PM instrument calibration/performance check • Impact of probe tip dilution • Impact of sample line temperature (active heating on and off) • Impact of engine power on the ratio of condensable to non-volatile particles• Effect of using a gas probe with downstream dilution for PM sampling• Mitigation of sampling problems due to changes in source Pressure

(See following charts)

Sample Line Transmission

Measurement Mono-disperse aerosol (stepped in size) and a dilution gas are injected into the sample lines at the bottom of the sampling rake and withdrawn from the sample manifold located near the instruments. Flow paths thus include the flex lines, probe selection box, converging manifold, main trunk lines, trunk line selection box, and sample manifold. Samples are drawn from the upstream and downstream ends of the lines through equal lengths of 3/8” ID conductive tubing.

Total flow through the lines are controlled with a metering valve/vacuum pump and maintained at ~50 LPM to simulate actual sampling conditions. Particle concentrations are measured with a single particle-counting CNC and subsequently corrected for variations in the upstream and downstream sample pressure.

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Particle Diameter (nm)

Unheated Sample Lines

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Heated Sampling Lines

Trunk-line B

Transmission Efficiencies

Heated Lines: Efficiencies >100% at smaller sizes

were reproducible and did not appear to be related to

nucleation of particles from materials out-gassed

from the tube walls.

Unheated Lines: Variations at smaller sizes may be due

to fluctuations in size of test aerosols. All lines exhibit

near 100% efficiency at D>100 nm

Sample Line Transmission Efficiency

Summary and Recommendations

• Technique of using mono-disperse test aerosols for line loss characterization was highly successful

and allowed a rapid, in-the-field assessment of particle losses though the main sampling system

components.

• Line losses were modest in unheated lines, largely agreed with predictions of empirical models,

and would typically lead to a < 10% underestimate of particle mass emissions for 100 ft lines.

• Line losses in heated lines were larger than predicted and could lead to >20% underestimate of

particle mass emissions.

• Losses at small sizes were underestimated in tests because of broad size range of the test aerosol

and losses that occurred within the long transport lines connecting the particle source to the test

apparatus; results were improved in the later validation test by use of a higher-resolution DMA.

• It is important to use single particle counting CN counter (TSI3010 or 3025) and correct for

pressure differences between the up- and downstream sampling locations.

Particle Sizing Instrument

Comparison

Results• CNC instruments compare within 30% of the reference CNC• Total number count using EEPS, SMPS and DMS vary significantly from reference CNC• Size distributions obtained with SMPS, EEPS and DMS are similar. Comparison at larger particle

sizes indicate– EEPS under-sizes particle distribution than indicated by SMPS and DMS peaks– DMS and EEPS over-predict total particle count– SMPS predicts lower count as the size distribution is close to its cut off size

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Particle size (Dp), nm

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ARI CNC NASA CNCAESO CNC UMR DMSUMR SMPS UTRC SMPSUTRC EEPS AESO EEPS

Total Count Comparison

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UMR DMS

UTRC EEPS

UTRC SMPS

UMR SMPS

Size Distribution Comparison

MAAP Mass Comparison

Results• Three MAAP instruments compared within 20% of each other

• Mass derived from SMPS size distribution at a uniform density is much higher than MAAP data, possibly due to

– Condensation of organic species, or

– Variation in mass density with particle size

• EC/OC data collected on filters will help to resolve some of the issues

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12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM

date and time

UTRC NASA ARI

Changes with Heating Sample Lines

Evaluation/Validation Test (F100-

200; mid-Nov 2008)

Test Objective Evaluate/validate the Interim PM Test Method by applying the methodology to an F100-220 as a

surrogate for the JSF F135 engine.

Approach/Requirements• F100-220 military engine test at Tinker AFB• Develop and utilize the probe-rake system and exhaust sampling hardware developed for the JSF F135 • Implement procedures defined in the Draft Interim PM Test Method

− Mount the linear probe-rake at the nozzle exit plane and traverse − Perform detailed spatial measurements across the exit plane at discrete engine powers from idle to military power (maximum power without afterburning)

• Analyze the data, identify deficiencies (if any) and correct the final Interim PM Test Method

Traverse Table

Test Cell Diffuser

Project Goal

Develop an accurate, Interim PM Test Method that provides:• Comprehensive PM characterization• 10X reduction in engine test time• 5X reduction in cost

Summary

• Interim PM Test Method has been developedo Fulfills need for JSF and other platformso Creative and cost effectiveo Solves many problems simultaneouslyo Advances science

• Validation/Evaluation measurements were successfully performed in Nov 2008 on an F100-220

• The Interim PM Test Method document has been drafted and will be finalized following a complete analysis of the Nov test data

• The spatially comprehensive Nov F100-220 test data will guide selective and a reduced number of spatial measurements required for the JSF F135 and thus reduce costly engine run time

• The Nov F100-220 data will be used to define the procedure for reporting engine representativeness

• PM characterization of an F100-220 engine using this methodology is a bonus to this project

Interim PM Test Method

Specifications

Nonvolatile Mass Measurement InstrumentsMulti-Angle Absorption Photometer (MAAP) was selected for mass measurements.

Particle NumberA condensation nucleus counter (CNC) was selected for particle counting and specified with a

lower size 50% cut point at 7 nm, an upper size cutoff at 1.0 micron, and must operate from 1.0 to 10E7 per cm3; (e g TSI Model 3022 or equivalent 3775).

Size DistributionA Scanning Differential Mobility Analyzer (e g SMPS) was selected for size distribution

measurements and is specified with a size range 7 to 250 nm (50% size cutoff points), a minimum of 30 size bins, scan times of less than or equal to 1.0 minute and a total count sensitivity from 1E3 to 1E7 particles per cm3.

Instrument Calibration ApproachA qualified calibration standard does not exit for calibration of instruments. Therefore, a process

based instrument comparison method was developed for the IPMTM.

Sampling Probe • Probe tip dilution is acceptable and probably scientifically preferred (more studies needed) • Gas probes with downstream dilution (within 6-8’ of the probe tip) will be considered for PM

measurements with a recommendation to be decided for the final document• The sampling probe tip should be water cooled due to anomalous APEX3 data with uncooled

rake & probes• The probe tip orifice diameter should be 0.060” or less (of course is coupled to dilution

criteria)• The dilution ratio should be greater than 4:1 (≥10:1 recommended); must assess tradeoff with

orifice diameter, flow rate, sample humidity, particle concentration and other potential particle processing parameters

• Sample line materials within the hot exhaust flow must be 316 SS or higher (inconel is acceptable).

Sample Line• Sample lines should not be actively heated/cooled for ambient temperatures of 25 ± 15 °C • Sample line section from the probe tip to just outside the exhaust flow should of minimum

length possible, ≥0.15” id and stainless steal (SS) material • An optional flexible section to allow traverse should be less than 4 m length, ≥ 0.30” id, and

made of SS or conductive flexible particle sampling line • The main trunk line section to the instruments should be less than 30 m length, ≥ ½” id, and SS • The total length should be as short as possible but not to exceed 36 m with a residence time

of less than 6 sec (calculated time for plug flow)• All SS lines should be seamless and have a minimum number of bends, fittings and valves • All valves should be full-bore ball valves (i.e. internal diameter of valve matches tubing id) • All bends should have a radius of curvature > 10 line radii

Sample Line Operation• Probe tips not being sampled should be back purged or should be diluted and pumped to

assure continuous flow• Diluent gas lines should not have active heating/cooling• Diluent gas must be HEPA-filtered dry Nitrogen• Exhaust sampling probe tips should be actively cooled• Sample lines must be leak checked from the probe tip to the instrument and demonstrated to

yield less than 5 particles/cc measured with a CPC when drawing ambient air through a HEPA filter at the probe tip

• The sample dilution ratio should be kept at greater than 10:1 over the engine power range to avoid water condensation and gas to particle conversion.

• Through dilution, the particle concentration should be kept to below 5E6/cm3 to avoid particle coagulation effects in the sample line.

• The instrument inlet sample line pressure must be within the pressure range specified by the instrument manufacturer.

• Excess flow should be vented to atmosphere to maintain instrument inlet sample pressure near ambient as specified by the instrument manufacturer.

• Sampling from multiple probe tips (ganged) may be required at low engine power to achieve required flow rate. The specified dilution ratio must be guaranteed per probe tip.

• Sample line penetration as a function of size should be measured and must be greater than 80% for particle sizes greater than 80 nm. Full penetration should be performed pre- and posttest.

• Sample line integrity with respect to leaks and penetration should be checked at least on a daily basis.

Distribution A; Approved for public release; distribution unlimited.