j. edebeli, l. durdina, c. spirig, j. g. anet
TRANSCRIPT
Motivation and objectivesBackground:
❖ Aircraft idle and taxi (low power modes) impact the air quality of airports and airport surroundings
❖ Emissions at these power modes are affected by the engine and ambient temperatures [1]
❖ ICAO certification low power thrust of 7% of rated take-off thrust (F00) at sea level in the international
standard atmosphere, 15 °C, 1 atm [2] differs from real world idle and taxi thrust, 2 to 10% F00 [3].
❖ Air quality models often use certification data from ICAO engine emissions databank [1].
But,
➢ What is the effect of ambient temperature on emission indices (EIs) of NOx, CO, HC, and non-volatile
particulate matter (nvPM) at low engine thrust?
➢ How do these EIs at real idle thrust compare with the ICAO reported EIs at 7% F00 ?Figure 1. LTO cycle showing the different power modes
ResultsTemperature (T), Thrust (%F00), and Emissions Indices (EIs) Real Idle/Taxi (RI) vs 7% F00 ICAO reported idle (E) EIs
Figure 2. Emission indices (EI) as a
function of ambient temperature and
colour-mapped by thrust in %F00
Figure 3. Box plots of the real idle emission indices (EIs) from cold engines (C,
shortly after start-up) and warm engines (W, after running at higher thrusts) in
comparison with EIs reported for 7% F00 in the ICAO engine emissions databank
(E) [6]. C, W, and E data are for the same types of CFM56-5 &7 (CF) and
P&W4000 (PW) series engines.
C and W (real idle) thrust: 2 to 9% F00
Implications➢ Estimations of the impacts of turbine engines on airport air quality using only ICAO engine emissions databank may not represent the true impact:
➢ One may overestimate the contribution of turbine engines to airport NOx and underestimate their contributions to airport CO and HC emissions.
➢ SCOPE11 calculated nvPM emission using reported smoke number tends to overestimate nvPM emissions from the engines presented here.
❖ Per engine, NOx, PMMass, and PMNum are ~28%, ~23%, ~250% overestimated; HC and CO are ~ 70% and 35% underestimated [Fuel flow and duration in mode considered].
➢ EICO, EIHC, EIMass, and EINum increase with decreasing ambient T; this may have implications for wintertime airport air quality in temperate regions.
Take home messages
✓ Calculated nvPM EIMass and EINum
from emissions databank reported
smoke number (SCOPE11) [5] are
higher than measured (real idle, RI)
nvPM EIMass and EINum.
✓ RI EICO and EIHC (C, W) are higher
than ICAO reported idle EIs.
✓ RI EICO are higher from the cold
engines.
✓ RI EIHC are higher from the cold
than from the warm CF engines.
✓ RI EINOx is lower than 7% ICAO
EINOx
✓ RI EINOx is higher from the warm
engines.
Methods Engine emissions were measured using the Swiss Mobile Aircraft Emissions Measurement System (SMARTEMIS), one of three global reference
systems for measuring aircraft emissions [4]. The system complies with ICAO methodology for engine emissions certification for nvPM. Data presented
here are from measurements conducted on large commercial turbofan engines (CFM56-5, CFM56-7, and Pratt & Whitney P&W4000 series engines)
being tested in dedicated engine emission tests as well as in parallel with engine tests after repair and overhaul at SR Technics at the Zurich Airport,
Switzerland. These experiments were conducted between 2013 and 2018.
Take home messages
✓ nVPM mass (EIMass) and nvPM
number emissions (EINum) decrease
with increasing ambient T.
✓ CO (EICO) and hydrocarbons (EIHC)
emissions also decrease with
increasing ambient T.
✓ NOx (EINOx) shows slight increase
with increasing ambient T.
✓ EICO, EIHC, and EINum are higher at
lower thrust.
✓ EINOx is higher at higher thrust.
✓ EIMass is slightly lower at higher
thrust.
References: [1] ICAO (International Civil Aviation Organization), 2011, Airport air quality manual, Doc 9889. [2] EASA (European Aviation Safety Agency), 2019, European aviation
environmental report 2019. [3] K. Morris, Report ENV/KMM/1126/14.8, British Airways, London, 2005. [4] Lobo P., L. Durdina, et al. Aerosol Sci. Technol, 2015,49, 472-484. [5]
Agarwal,A., R.L. Speth, et al., Environ. Sci. Technol., 2019, 53, 1364-1373 [6] EASA (European Aviation Safety Agency), 2019, ICAO Aircraft Engine Emissions Databank (Updated
September, 2019. Available at: https://www.easa.europa.eu/easa-and-you/environment/icao-aircraft-engine-emissions-databank. Accessed 25.09.2019.
Acknowledgement: Dr. B. T. Brem (Paul Scherrer Institute, Switzerland); SR Technics, Zurich Switzerland; this project was funded by the Swiss Federal Office of Civil
Aviation (FOCA) – Projects APRIDE
Real aircraft idle emissions: Ambient temperature
dependence and comparison with ICAO reported emissionsJ. Edebeli, L. Durdina, C. Spirig, J. G. AnetZurich University of Applied Sciences, ZHAW, Winterthur, SwitzerlandContact: [email protected]
Measured emissions were obtained using a state-of-the-art standardized sampling system for large in-service commercial turbofan engines [4]
ANOVA p EI(T) ANOVA p EI(%F00)
EIMass 3 × 10-9 9 × 10-3
EINum 5 × 10-13 3 × 10-17
EICO 2 × 10-6 6 × 10-88
EIHC 2 × 10-24 3 × 10-28
EINOx 3 × 10-5 4 × 10-60
Table 1: Significance of the dependence of EIs on ambient T and %F00 (slope ≠ 0); α = 0.05
0.1
1
10
100
0.1
1
10
0
40
80
120
0
20
40
0 10 20 300
2
4
6
CFM56-5,7 series PW4000 series
EI M
ass (
mg
/kg
fue
l)
3.04.05.06.07.0
%F00
PMMass
EI N
um
(#*1
014/k
gfu
el)
PMNum
EI C
O (
g/k
gfu
el) CO
EI H
C (
g/k
gfu
el) HC
EI N
Ox (
g/k
gfu
el)
Ambient T °C
NOx
0.01
0.1
1
10
100
EI M
ass (
mg/k
gfu
el)
PMMass
0.1
1
10
EI N
um
(#*1
01
4/k
gfu
el)
PMMass
0
40
80
120
EI C
O (
g/k
gfu
el) CO
0
20
40
EI H
C (
g/k
gfu
el)
HC
C W E
CF PW CF PW CF PW0
2
4
6
EI N
Ox (
g/k
gfu
el)
NOx