Design of Aircraft Trajectories Based on Trade-Offs Between Emission Sources 6-3-11

7/30/2019 Design of Aircraft Trajectories Based on Trade-Offs Between Emission Sources 6-3-11

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Design of Aircraft Trajectories based on Trade-offs

between Emission Sources

Banavar Sridhar and Neil Chen

NASA Ames Research CenterMoffett Field, CA, USA

USA/Europe Air Traffic Management Research and Development Seminar

Berlin, Germany

June 13-16, 2011

Hok Ng

University of California,

Santa Cruz, CA, USA

Florian Linke

DLR-German Aerospace

Center, Hamburg, Germany


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Impact of Aviation on Climate Change*

Increased urgency to deal with factors affecting climatechange

Climatic changes include Direct emissions: CO2 , Water vapor and other greenhouse

gasses (GHG) (best understood)

Indirect effects: NOx affecting distributions of Ozone andMethane (Ozone and Methane effects have opposite signs)

Effects associated with contrails and cirrus cloud formation Aviation responsible for 2% of all anthropogenic CO2

emissions Large uncertainty in the understanding of the impact of

aviation on climate change*Workshop on the Impacts of Aviation on Climate Change, June 7-9, 2006, Boston, MA.

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Research Projects

NASA/FAA research on understanding the atmosphericphysics and chemistry and weather forecasting

FAA environmental tool development Environmentally Responsible Aviation (ERA)

Vehicle concepts and enabling technologies that will reduce theimpact of aviation on the environment

Research in Europe Climate compatible Air Transport System (CATS)

Research limited to Modeling, data analysis andoperational concepts

Inclusion of environmental factors based on climate scienceresearch and ERA technologies in airspace simulations to

evaluate alternate concepts and policies

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Outline

Modeling approach Persistent contrails formation model Aircraft fuel burn model Wind optimal contrails avoidance aircraft trajectories Tradeoff between persistent contrails mitigation and

extra fuel burn

Concluding remarks

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Approach

Flight

Schedules

Atmospheric

and Air SpaceData

Future ATM

Concepts

Evaluation

Tool

(FACET)

Visualization

andAnalysis of

Aircraft

Operations

Application Programming Interface

Optimization Algorithms

- System level- Aircraft level

Emission

Models andMetrics

Contrail

Models

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Contrails

Aircraft condensation trails occur whenwarm engine exhaust gases and cold

ambient air interact

Contrails form when Relative Humiditywith respect to Water (RHW) >

Temperature dependent threshold

Persist when Relative Humidity withrespect to Ice (RHI) >100%

Contribution of contrails to globalwarming may be larger than contribution

from CO2 emissions

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http://www.nature.com/nclimate/journal/v1/n1/full/nclimate1078.html


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Persistent Contrail Formation Model

Persistent Contrail

Rhi>100%

Aircraft

RHW Contours RHI Contours

RHI>100% Contours 7


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Fuel Consumption Model (BADA)

Eurocontrols Base of Aircraft DAta (BADA) Fuel burn during cruise:fc = t SFCTh

Fuel burn for a typical jet from Chicago to Newark

Fuel burn in kg

Altitude in 100 ft


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Emission Models(Systems for Assessing Aviations Global Emissions)

e(CO2) = 3155

e(H2O) =1237

e(SO2) = 0.8

e(HC) = EIHC

e(CO) = EICO

e(NOx) = EINO

x

Fuel and emission models undergoing additional verification usingAviation Environmental Design Tool (AEDT)

Collaboration with Volpe National Transportation Systems Center


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Find the optimal trajectory given the arrival and departure airports,cruise speed and winds subject to environmental constraints

Optimization performed in the horizontal plane for different cruisealtitudes

Aircraft equations of motion in the horizontal plane are

Optimal Aircraft Trajectories

x = Vcos+ u(x,y)

y = Vsin+ v(x,y) subject to

Th =D

L =W

m = f

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Optimization Subject to

Environmental Constraints

Optimize horizontal trajectory by determining the headingangle that minimizes the cost function

Solution reduces to solvingJ=1/2X

T(tf )MX(tf ) + [Ct

t0

tf

+Cf f +Cr r (x,y)]dt

x = Vcos+ u(x,y)

y = Vsin+ v(x,y)

= (V+ u(x,y) cos+ v(x,y)sin)(Ct+Cf f+Crr(x,y)) (

Cr sin

r(x,y)

x+

Cr cos

r(x,y)

y )

+ sin2(

v(x,y)

x)+ sin cos(

u(x,y)

xv(x,y)

y) cos

2(

u(x,y)

y)

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Time cost

Fuel cost

Contrails penalty cost


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Contrail Reducing Aircraft Trajectories

Wind Optimal

Complete ContrailReduction

Partial Contrail

Reduction

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Tradeoff between Contrail Reduction and

Extra Fuel Consumption

JFK/LAX (2D)

LAX/JFK (2D)

LAX/JFK (3D)

JFK/LAX (3D)

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Optimal Trajectories for 12 City Pairs

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Persistent contrails

at 33,000 ft


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Results for 12 City-pairs

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One days simulation is just the beginning!

Total (2D)

Total (3D)


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Climate Impact of Emissions

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Uncertainty Quantification

Each trade-off curve requires approximately 73,000simulations

Some of the uncertainties Daily variation of traffic and atmospheric conditions Aircraft parameters: Thrust, Weights (variation of 15%), Fuelflow Atmospheric parameters: Relative humidity, Winds Quantity, location and lifetime of emission Climate impact (Radiative Forcing) of emission Emission Goals (10/20/50/100 years, Carbon neutral/reduce) How much can we afford?

Magnitude of uncertainty and importance to decision-making

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Daily variations in the trade-off of emissions

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2D

3D

May 27

May 4

May 24


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Variation in Contrail Regions due to

Uncertainty in RHW Measurements

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Effect of RHW Uncertainty on Emission

Tradeoff

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10%

5%

2%

Nominal

2D

3D


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Concluding Remarks

Presented research on environmentally friendlyen route traffic flow concepts incorporatingmodels developed by basic climate research

Developed an optimal contrail reduction trajectoryconcept

Investigated the tradeoff between persistent contrailsformation and additional fuel burn

When altitude and route are optimized, a small increase(2%) in total fuel consumption can significantly (30 to

60%) reduce the total travel times through contrail regions

Developed capability to conduct system levelanalysis of Traffic Flow Management concepts

with environmental impact

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Design of Aircraft Trajectories Based on Trade-Offs Between Emission Sources 6-3-11