Overview and Highlights of the Alternative Aviation Fuel ... · Bruce Anderson, NASA LaRC June 10, 2009 - 7 Primary Exhaust Measurements • CO 2, CO, THC, NOx and Smoke Number •

June 10, 2009 - 1 Bruce Anderson, NASA LaRC

Overview and Highlights of the Alternative Aviation Fuel Experiment

Bruce Anderson and the AAFEX Science Team

June 10, 2009 - 2 Bruce Anderson, NASA LaRC

Motivation for Seeking Alternative Fuels

• Almost 60% of US oil is imported—will increase to 70% by 2025

• Large fraction of imported oil comes from unfriendly/unstable nations—leaves us vulnerable to embargoes and terrorist threats

• Worldwide demand is increasing—fuel prices have doubled in two years, causing large increases in transportation costs

• Increasing domestic oil production may come at a high environmental price (ANWAR, offshore, etc.)

• Fossil fuels are non-renewable, cause increases in atmospheric greenhouse gas concentrations

Fuel costs are now the largest expense in civil aviation—increasing and fluctuating prices are causing an economic crisis in the industry

June 10, 2009 - 3 Bruce Anderson, NASA LaRC

AAFEX Objectives

1) Examine the effects of alternative fuels on engine performance and emissions

2) Investigate the factors that control volatile aerosol formation and growth in aging aircraft exhaust plumes

3) Establish aircraft APU emission characteristics and examine their dependence on fuel composition

4) Evaluate new instruments and sampling techniques

5) Inter-compare measurements from different groups to establish expected range of variation between test venues

June 10, 2009 - 4 Bruce Anderson, NASA LaRC

Summary of AAFEX Test Plan

Location: NASA Dryden Aircraft Operation Facility

Dates: January 20 – February 3, 2009

Sponsors: NASA, Air Force, EPA, FAA

Aircraft: DC-8 with CFM56-2 engines

Fuels: 1--Standard JP-8 2--Shell Fischer-Tropsch Fuel from Natural Gas (FT1) 3--50/50 JP-8/FT1 blend 4--Sasol Fischer-Tropsch fuel from Coal (FT2) 5--50/50 JP-8/FT2 blend

Runtime: ~35 hours total

June 10, 2009 - 5 Bruce Anderson, NASA LaRC

5 10 15 20 25 30 Time-->

C11

C12

C10 C9

C8

Shell Fischer-Tropsch Kerosene 0% Aromatics, 0 ppm Sulfur

Con

cent

rati

on

5 10 15 20 25 30 0

C11 C12

C13

C14

C15

C16

C17 C18

C10

C9

C8

C7

C19

Standard JP-8 Jet Fuel 19% Aromatics, 1200 ppm Sulfur

Carbon Spectra for AAFEX Fuels

Chromatographic Column Elution Time ->

June 10, 2009 - 6 Bruce Anderson, NASA LaRC

AAFEX Test Site Arrangement

Boeing, GE, Pratt and Whitney, CMU, Harvard, MSU, UCSD, and UTRC also participated

June 10, 2009 - 7 Bruce Anderson, NASA LaRC

Primary Exhaust Measurements

• CO2, CO, THC, NOx and Smoke Number

• Hazardous Air Pollutants + Green House Gases

• Total Particle and Black Carbon Mass (TEOM, LII, MAAP)

• Particle Number Density and Size Distribution (CPC, SMPS, EEPS, DMS-500)

• Size-resolved Aerosol Composition (AMS)

• Bulk Aerosol Composition (PILS\IC)

• Black carbon morphology (Electron Microscopy)

• Cloud Condensation Nuclei (DMT CCN)

• Aerosol Isotopes

June 10, 2009 - 8 Bruce Anderson, NASA LaRC

Exhaust Sample Inlets at 1, 30 and 145 m

Identical 1 and 30 m inlets behind left and right inboard engines

June 10, 2009 - 9 Bruce Anderson, NASA LaRC

Plume chemistry studied with mobile van and 150m Trailer

Aerodyne van and downstream trailers

equipped with sensitive particle and trace gas

sensors

Van drove back and forth across exhaust plume at

increasing distances as the aircraft was idling

June 10, 2009 - 10 Bruce Anderson, NASA LaRC

Temperature Context for Test Runs

Mapping

JP-8

Blend-2

JP-8

FT-1

APU

FT-2

FT-1

FT-2

Blend-1

JP-8

JP-8 APU

JP-8

The experiment matrix included 13 engine and 3 APU test runs; burned >25,000 gallons of fuel in over 35 hours of testing.

June 10, 2009 - 11 Bruce Anderson, NASA LaRC

Fuel Effects on Particle Size

10 100

0

1x1015

2x1015

JP-8 FT2 Bld2

Num

ber E

I (#/

kg/d

Log(

Dp))

Particle Diameter (nm)10 100

0

1x1015

2x1015

JP-8 FT2 Bld2

Num

ber E

I (#/

kg/d

Log(

Dp))

Particle Diameter (nm)

65% power, 1 m inlet 30% power, 1 m inlet

• Particle size highly dependent on fuel composition • Particle concentrations only slightly above background in FT plume at low engine powers • Lack of aromatics suppresses soot formation even at high power • Lack of sulfur and aromatics reduces rates of volatile aerosol nucleation in sampling lines

June 10, 2009 - 12 Bruce Anderson, NASA LaRC

Fuel Effects on Particle Number Concentrations

Number emissions 98% lower at idle, 40% at takeoff power

Emission reduction disproportionate to fraction of

FT fuel in blend

Nonvolatile Aerosols @ 1m Differences in emissions greatest at idle, less at higher engine powers

0 20 40 60 80 1000

20

40

60

80

100

Num

ber E

I Red

uctio

n (%

)

Engine Power (%)

100% FT1 50/50 Blend

June 10, 2009 - 13 Bruce Anderson, NASA LaRC

Mass emissions 80% lower at idle, 50% at takeoff power

Blended fuel reduced mass

emissions by >50% at all powers.

Fuel Effects on Particle Mass Concentrations

0 20 40 60 80 1000

20

40

60

80

100

Blac

k Ca

rbon

EI R

educ

tion

(%)

Engine Power (%)

100% FT1 50/50 Blend

Nonvolatile Aerosols @ 1m Differences in emissions greatest at idle, less at higher engine powers

June 10, 2009 - 14 Bruce Anderson, NASA LaRC

ambient mode removed The port engine is typically a bit higher,

consistent with its higher EI-soot.

Pure FT Fuels have no

measurable SO4 contribution (at detection limit)

Data Courtesy of Aerodyne

Fuel Effects on Sulfate Emissions

June 10, 2009 - 15 Bruce Anderson, NASA LaRC

Like SO4, organic PM contributions

decrease for FT fuels.

Note: Non-volatile PM and associated surface area also

decrease for FT fuels.

Whether gas phase condensable species

decrease with FT fuels cannot be

determined or ruled out by this

measurement alone.

Data Courtesy of Aerodyne

Fuel Effects on Organic Aerosol Emissions

June 10, 2009 - 16 Bruce Anderson, NASA LaRC

-5 0 5 10 15 200

50

100

150

200

250

300

Parti

cle M

ass

EI (m

g/kg

)

Ambient Temperature (C)

Total Mass

Black Carbon

Volatile Aerosol Formation Dependent on Temperature

JP-8 Fuel, Ground Idle, 30 m inlet

Data very important for developing and validating plume models

June 10, 2009 - 17 Bruce Anderson, NASA LaRC

Volatile Aerosols Growth Depends on T and t

June 10, 2009 - 18 Bruce Anderson, NASA LaRC

AFFEX Summary 1) Alterative fuels do not effect engine performance, but

may cause fuel leaks

2) Engine black carbon, sulfate, and organic aerosol emissions substantially reduced when burning FT fuels

3) Aircraft engine consumes ambient methane at most power settings

4) At idle, APU emits ~25x more BC mass per kg fuel burned than DC-8 engine

4) APU emissions similarly reduced by burning FT fuels

5) Great deal was learned about temperature dependence of AC emissions—will be used to parameterize emission profiles for local air quality modeling

***Data Workshop will be held January 8th in Orlando***