Take-off Cycle Research Articles

Calculation of aircraft fuel consumption and CO2 emissions based on path profile estimation by clustering and registration

In this paper, typical flight paths, fuel burn and carbon dioxide (CO2) emissions are computed using a rich data set and two estimation approaches: (i) a clustering and landmark registration technique and (ii) a method based on the EUROCONTROL’s Base of Aircraft Data (BADA) performance model. Clustering is employed to extract flight characteristics and organize altitude profiles accordingly. Our flight path and CO2 emissions analysis focuses on the Climb-Cruise-Descent (CCD) cycle, since different operational conditions during the Landing and Take-off cycle may result in significant deviations in terms of fuel burn and CO2 emissions and different modeling assumptions and approaches should be adopted. The key features of the CCD cycle are the flight distance, the aircraft type and the flight direction. Path segmentation and landmark registration are employed for path representation and smoothening of discontinuities. The paths estimated by the above method are compared to those obtained by the point mass BADA model. Noticeable deviations in the resulting estimates of the operational characteristics are found. Higher deviations in prediction errors are found in the climb and descent duration and the rate of climb and descent. The typical altitude profiles obtained by the two methods are used to determine fuel burn and CO2 emissions. The difference in the resulting estimates are less stark; on a fleet-wide level the fuel burn of the relevant typical profiles differ by 7%. Emission maps of the U.S. airspace enabling the identification of critical emission spots including routes, airports, seasons and aircraft type are constructed.

Investigating actual landing and takeoff operations for time-in-mode, fuel and emissions parameters on domestic routes in Turkey

Operational landing and takeoff standards developed by the International Civil Aviation Organization (ICAO) in the 1970s, have been widely-used in fuel consumption and emissions models or inventory studies. However, these generic standards may cause significant uncertainties due to changes in the air transport system over time and appear to remain highly conservative. To quantify the uncertainty caused by using generic operational standards, in this study, the effects of actual fuel flow and time-in-mode of more than 9000 different domestic flights, performed by five different narrow-bodied aircraft models with seven different engine, on the averages of landing and takeoff fuel burn and emissions are investigated. Compared to the simple approach, suggested by the ICAO, results indicate considerably lower time in mode averages, particularly during taxi-out (42%) and climb (45%) phases, even for high traffic volume airports. The greatest differences in fuel flow are observed during takeoff and approach phases. As a result of using actual time-in-mode and fuel flow data, the actual landing and takeoff fuel burn averages are found to be 35% lower than ICAO values. In addition, the effects of low altitude level flight on approach phase fuel flow, thrust reverser mode on taxi-in phase fuel flow, and stop and acceleration of aircraft on taxi ways on fuel flow are discussed. With regard to emissions, using actual time-in-mode and fuel flow data, landing and takeoff cycle hydrocarbon and carbon monoxide emissions are found to be 34% lower, while nitrogen oxide emissions are found to be 38% lower than those given by the ICAO database. Analyses related to the effects of aircraft mass on emissions indicate that the differences for carbon monoxide and nitrogen oxides between the lightest and heaviest aircraft are 3% and −26%, respectively. The analyses results reveal that uncertainties in landing and takeoff fuel burn and emissions caused by considering ICAO time-in-modes can be significantly higher compared to those caused by considering ICAO fuel flow standards.

Statistical modeling of the fuel flow rate of GA piston engine aircraft using flight operational data

The United States has the largest and most diverse general aviation (GA) community in the world, with more than 220,000 aircraft, flying almost 23million hours annually. Accurate and economic estimating the exhaust emissions of general aviation will effectively support the practice of mitigating the environmental impacts from general aviation. Fuel flow rate in each phase of the Landing and Takeoff Cycle is one of the necessary factors recommended by the International Civil Aviation Organization to be used to estimate the exhaust emissions. This paper explores statistical models of predicting the fuel flow rate of piston-engine aircraft using general aviation flight operational data, including the aircraft altitude, the ground speed, and the vertical speed. A machine learning technique is applied to adapt the variability of flight operational data due to flexible operations of general aviation and random errors in flight data. The Classification and Regression Trees (CART) and the Smoothing Spline ANOVA (SS-ANOVA) are adopted as the modeling approaches. The modeling results are compared and interpreted from the standpoint of general aviation phases of flight in the Landing and Takeoff Cycle. Both models demonstrate good accuracy in predicting the fuel flow rate. The CART model provides intuitive outputs by the phases of flight, and is more robust to flight data outliers. The SS-ANOVA model is relatively more accurate in predicting the fuel flow rate, and is better at explaining the interaction between variables. A robust fuel flow rate prediction model of predicting the fuel flow rate of piston-engine aircraft is believed to be practical and economic for GA exhaust emissions estimation.

Assessment of Particle Pollution from Jetliners: from Smoke Visibility to Nanoparticle Counting.

Aviation is a substantial and a fast growing emissions source. Besides greenhouse gases, aircraft engines emit black carbon (BC), a climate forcer and air pollutant. Aviation BC emissions have been regulated and estimated through exhaust smoke visibility (smoke number). Their impacts are poorly understood because emission inventories lack representative data. Here, we measured BC mass and number-based emissions of the most popular airliner's engines according to a new emission standard. We used a calibrated engine performance model to determine the emissions on the ground, at cruise altitude, and over entire flight missions. Compared to previous estimates, we found up to a factor of 4 less BC mass emitted from the standardized landing and takeoff cycle and up to a factor of 40 less during taxiing. However, the taxi phase accounted for up to 30% of the total BC number emissions. Depending on the fuel composition and flight distance, the mass and number-based emission indices (/kg fuel burned) were 6.2-14.7 mg and 2.8 × 1014 - 8.7 × 1014, respectively. The BC mass emissions per passenger-km were similar to gasoline vehicles, but the number-based emissions were relatively higher, comparable to old diesel vehicles. This study provides representative data for models and will lead to more accurate assessments of environmental impacts of aviation.

Trajectory Modelling of Atmospheric Pollutants Associated with Aircraft Emissions for Air Quality Assessment

Aviation is suffering a large increase in recent years and as result there is a consequent increase in emissions of air pollutants. The highest exposure levels of air pollution in airports and near them are found in the Landing and Take-off (LTO) cycle responsible for negative impacts on air quality. The city of Rio de Janeiro, in the coastal region of the South East of Brazil, has two major airports; the International airport and one for domestic flights. Both are near the Guanabara Bay (GB), in Metropolitan Region of Rio de Janeiro (MRRJ). In this research, it was verified the pollutant trajectories emitted by these two airports using the Brazilian Regional Atmospheric Modelling System (BRAMS) to generate wind fields in the MRRJ. From the wind fields, 3D kinematic trajectories Lagrangian model was used to calculate the pollutant trajectories. Atmospheric instability indices were tested from the BRAMS simulations to verify the days with more stable atmospheric conditions in winter month. The Total Totals index (TT) was selected to be more appropriate for the purpose of this study. Obtained results showed that the cities of Rio de Janeiro and Duque de Caxias, in the western of the MRRJ, are critical points to be affected continually by pollutant transport due to the prevailing meteorological conditions, harming the air quality in the region. These models captured the influence of mesoscale and large-scale systems, showing the dependence of the trajectories of both systems related to the season and time of day. They are important tools in decision-making for the control of emissions, contributing to better management of urban air quality.

Emissions from passenger aircraft at Kayseri Airport, Turkey

This paper presents the estimation of pollutant gas emissions including nitrogen oxides (NOx), hydrocarbons (HC), and carbon monoxide (CO), from aircraft during landing and take-off (LTO) cycles for the year 2010 at Kayseri Airport in Turkey. Emission calculations were carried out using the flight data recorded by the State Airports Authority and International Civil Aviation Organization (ICAO) - Engine Emission Data Bank (EEDB) used for calculations. The total landing and take-off pollutant emissions from aircrafts were calculated as 177.90 t/y (8.4 t/y for HC, 66.90 t/y for CO, and 102.64 t/y for NOx) at Kayseri Airport in 2010. It is estimated that a decrease of 2 min in taxiing time causes a decrease of approximately 4% in LTO emissions. An increase of 25% in landing and take-off cycles causes an increase of around 11% in pollutant emissions. Domestic flights were responsible for 68% of the total LTO emissions from all flights at Kayseri Airport in 2010.

Parametric Modeling Investigation for Radially Staged Low-Emission Combustion

Aviation gas-turbine combustion demands high efficiency, wide operability, and minimal trace gas emissions. Performance critical design parameters include injector geometry, combustor layout, fuel–air mixing, and engine cycle conditions. The present investigation explores these factors and their impact on a radially staged low-emission aviation combustor sized for a next-generation 24,000-lbf-thrust engine. By coupling multifidelity computational tools, a design exploration was performed using a parameterized annular combustor sector at projected 100% takeoff power conditions. Design objectives included nitrogen oxide emission indices and overall combustor pressure loss. From the design space, an optimal configuration was selected and simulated at 7.1, 30, and 85% part-power operation, corresponding to landing–takeoff cycle idle, approach, and climb segments. All results were obtained by solution of the steady-state Reynolds-averaged Navier–Stokes equations. Species concentrations were solved directly using a reduced 19-step reaction mechanism for Jet A. Turbulence closure was obtained using a nonlinear model. This research demonstrates revolutionary combustor design exploration enabled by multifidelity physics-based simulation.

Emission characteristics of a model combustor for aero gas turbine application

A TeLESS concept combustor using lean staged NOx reduction technology has been proposed on the basis of previous studies. TeLESS means the Technology of Low Emissions of Stirred Swirl in this paper. As the power condition increases, the TeLESS combustor will work in low power mode, circumferentially staged mode, or high power mode. Meanwhile, each combustor dome is in either only pilot mode or two stages mode. Emission characteristics of TeLESS combustor have been investigated experimentally in a single-module rectangular model combustor. NOx emissions and combustion efficiency of the model combustor were measured under high pressures and temperatures up to 2.8MPa and 845K. Fuel stage ratio ranged from 1.5% to 34.9% in the tests. The fuel staging effects on NOx emissions, combustion efficiency and stability of the model combustor were studied under circumferentially-staged mode and high power mode conditions. Tests results showed that the optimal fuel stage ratio for the combustor varied with operating conditions. A new empirical NOx model, based on the idea of flame partition, was proposed for staged combustion. Combustor pressure, inlet temperature, and dome equivalence ratio, as well as the dome fuel stage ratio were used as input parameters in the NOx model. Finally, the empirical model was used to predict landing and take-off cycle NOx emissions for the TeLESS combustor.

AVIATION – ENVIRONMENTAL THREATS

Based on the available information and authors self-assessments, this article presents turbine engine exhaust gases effect on the environment, especially near to the aircraft and helicopters during their engines idle setting and take-offs. The concentration level of pollutants in gas turbine exhaust and its relation to the temperature and time of the combustion process is discussed. The article presents diffusion of the aircraft turbine engine exhaust in the airport area, focusing on aircraft take-off manoeuvre. The authors would like to draw attention of the aviation professionals to the fact that amount of exhaust from the turbine engine is so significant that may adversely change the ambient air near to the aircraft. Consequently, smaller amount of oxygen with increased level of carbon monoxide during engine start –up and idle can be a threat to the maintenance staff health. Also high emission level of the nitrogen oxides, especially during take-off and climb is indifferent for the environment. The paper gives an example of real fuel consumption and toxic gases emissions in the so-called landing and takeoff cycle (LTO) and during long-range flight. Turbine engines noise distribution and its intensity because of complex aerodynamic and thermodynamic processes is presented.

Experimental and numerical studies of a lean-burn internally-staged combustor

A lean-burn internally-staged combustor for low emissions that can be used in civil aviation gas turbines is introduced in this paper. The main stage is designed and optimized in terms of fuel evaporation ratio, fuel/air pre-mixture uniformity, and particle residence time using commercial computational fluid dynamics (CFD) software. A single-module rectangular combustor is adopted in performance tests including lean ignition, lean blowout, combustion efficiency, emissions, and combustion oscillation using aviation kerosene. Furthermore, nitrogen oxides (NOx) emission is also predicted using CFD simulation to compare with test results. Under normal inlet temperature, this combustor can be ignited easily with normal and negative inlet pressures. The lean blowout fuel/air ratio (LBO FAR) at the idle condition is 0.0049. The fuel split proportions between the pilot and main stages are determined through balancing emissions, combustion efficiency, and combustion oscillation. Within the landing and take-off (LTO) cycle, this combustor enables 42% NOx reduction of the standard set by the 6th Committee on Aviation Environmental Protection (CAEP/6) with high combustion efficiency. The maximum board-band pressure oscillations of inlet air and fuel are below 1% of total pressure during steady-state operations at the LTO cycle specific conditions.

Development of a Simple and Cost-Effective Bead-Milling Method for DNA Extraction from Fish Muscles

In the fish food sector, due to a growing globalization of the market, where intentional and unintentional frauds reach alarming levels, the molecular analysis is increasingly used by both official agencies, to enforce the law on traceability, and private companies, to verify the quality of goods. DNA extraction represents a necessary and critical step for all types of DNA analysis. Among the drawbacks associated with this procedure, there are handling of toxic materials, low DNA yield, and low throughput, due to time-consuming manual procedures. In this work, to overcome some of these problems, we developed an alternative method based on a bead-milling procedure without proteinase K digestion. The new method was then compared with both a salting-out protocol, developed in a previous work, and a commercial kit. Yield, spectrophotometric purity, electrophoretic degradation pattern, and amplificability of the extracted DNA were assessed. In particular, DNA amplificability was evaluated by comparing the band intensity on the gel, after amplification of the 16S rRNA and cytochrome oxidase I genes with a conventional PCR, and the take-off cycles, after amplification of the 16S rRNA gene with a real-time PCR. The results showed that the bead-based method allowed to obtain acceptable amounts of DNA, with good purity and good characteristics of amplificability. Although the salting-out method remains the most effective protocol in terms of pure performances, the bead-milling procedure can be considered a valid alternative, in the light of its lower demand in terms of labor and costs.

Analysis of environmental benefits resulting from use of hydrogen technology in handling operations at airports

Airports and nearby areas are currently facing an increasing pollution due to the growth of air transport traffic. Airport air pollution is produced not only by aircraft during landing and take-off cycles but also by the ground support equipment (GSE) during the airport handling activities. This paper investigates the potential of hydrogen as an alternative fuel for GSE vehicles to mitigate the airport air pollution. For this purpose, a methodology is developed to assess the environmental benefits attainable with the introduction of hydrogen technology for GSE vehicles powered by proton exchange membrane (PEM) fuel cells. This methodology compares, for a given scenario, the direct emissions produced by fuel combustion and the indirect emissions related to fuel production for both diesel and hydrogen technologies. Steam methane reforming and electrolysis technologies are investigated for the production of gaseous hydrogen at the airport. The pollutants investigated comprise carbon monoxide, total hydrocarbons, nitrogen oxides, sulphur oxides, particulate matter and volatile organic compounds. The main inputs for the methodology are the number of air transport movements, the aircraft fleet mix, the turnaround times for handling operations, the type of GSEs used, and the ratio of GSE vehicles converted to hydrogen (type, power installed, etc.). A preliminary cost analysis of a ground power unit powered by PEM fuel cells is also presented. The airport planners and policy makers can use this study to define a feasible environmental policy based on the use of new technologies such as hydrogen.

The global impact of the transport sectors on atmospheric aerosol: simulations for year 2000 emissions

Abstract. We use the EMAC (ECHAM/MESSy Atmospheric Chemistry) global model with the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications) to quantify the impact of transport emissions (land transport, shipping and aviation) on the global aerosol. We consider a present-day (2000) scenario according to the CMIP5 (Climate Model Intercomparison Project Phase 5) emission data set developed in support of the IPCC (Intergovernmental Panel on Climate Change) Fifth Assessment Report. The model takes into account particle mass and number emissions: The latter are derived from mass emissions under different assumptions on the size distribution of particles emitted by the three transport sectors. Additional sensitivity experiments are performed to quantify the effects of the uncertainties behind such assumptions. The model simulations show that the impact of the transport sectors closely matches the emission patterns. Land transport is the most important source of black carbon (BC) pollution in the USA, Europe and the Arabian Peninsula, contributing up to 60–70% of the total surface-level BC concentration in these regions. Shipping contributes about 40–60% of the total aerosol sulfate surface-level concentration along the most-traveled routes of the northern Atlantic and northern Pacific oceans, with a significant impact (~ 10–20%) along the coastlines. Aviation mostly affects aerosol number, contributing about 30–40% of the particle number concentration in the northern midlatitudes' upper troposphere (7–12 km), although significant effects are also simulated at the ground, due to the emissions from landing and take-off cycles. The transport-induced perturbations to the particle number concentrations are very sensitive to the assumptions on the size distribution of emitted particles, with the largest uncertainties (about one order of magnitude) obtained for the land transport sector. The simulated climate impacts, due to aerosol direct and indirect effects, are strongest for the shipping sector, in the range of −222.0 to −153.3 mW m−2, as a consequence of the large impact of sulfate aerosol on low marine clouds and their optical properties.

A plume-in-grid approach to characterize air quality impacts of aircraft emissions at the Hartsfield–Jackson Atlanta International Airport

Abstract. This study examined the impacts of aircraft emissions during the landing and takeoff cycle on PM2.5 concentrations during the months of June and July 2002 at the Hartsfield–Jackson Atlanta International Airport. Primary and secondary pollutants were modeled using the Advanced Modeling System for Transport, Emissions, Reactions, and Deposition of Atmospheric Matter (AMSTERDAM). AMSTERDAM is a modified version of the Community Multiscale Air Quality (CMAQ) model that incorporates a plume-in-grid process to simulate emissions sources of interest at a finer scale than can be achieved using CMAQ's model grid. Three fundamental issues were investigated: the effects of aircraft on PM2.5 concentrations throughout northern Georgia, the differences resulting from use of AMSTERDAM's plume-in-grid process rather than a traditional CMAQ simulation, and the concentrations observed in aircraft plumes at subgrid scales. Comparison of model results with an air quality monitor located in the vicinity of the airport found that normalized mean bias ranges from −77.5% to 6.2% and normalized mean error ranges from 40.4% to 77.5%, varying by species. Aircraft influence average PM2.5 concentrations by up to 0.232 μg m−3 near the airport and by 0.001–0.007 μg m−3 throughout the Atlanta metro area. The plume-in-grid process increases concentrations of secondary PM pollutants by 0.005–0.020 μg m−3 (compared to the traditional grid-based treatment) but reduces the concentration of non-reactive primary PM pollutants by up to 0.010 μg m−3, with changes concentrated near the airport. Examination of subgrid-scale results indicates that median aircraft contribution to grid cells is higher than median puff concentration in the airport's grid cell and outside of a 20 km × 20 km square area centered on the airport, while in a 12 km × 12 km square ring centered on the airport, puffs have median concentrations over an order of magnitude higher than aircraft contribution to the grid cells. Maximum puff impacts are seen within the 12 km × 12 km ring, not in the airport's own grid cell, while maximum grid cell impacts occur within the airport's grid cell. Twenty-one (21)% of all aircraft-related puffs from the Atlanta airport have at least 0.1 μg m−3 PM2.5 concentrations. Near the airport, median daily puff concentrations vary between 0.017 and 0.134 μg m−3 (0.05 and 0.35 μg m−3 at ground level), while maximum daily puff concentrations vary between 6.1 and 42.1 μg m−3 (7.5 and 42.1 μg m−3 at ground level) during the 2-month period. In contrast, median daily aircraft contribution to grid concentrations varies between 0.015 and 0.091 μg m−3 (0.09 and 0.40 μg m−3 at ground level), while the maximum varies between 0.75 and 2.55 μg m−3 (0.75 and 2.0 μg m−3 at ground level). Future researchers may consider using a plume-in-grid process, such as the one used here, to understand the impacts of aircraft emissions at other airports, for proposed future airports, for airport expansion projects under various future scenarios, and for other national-scale studies specifically when the maximum impacts at fine scales are of interest.

Emission Reduction of Fuel-Staged Aircraft Engine Combustor Using an Additional Premixed Fuel Nozzle.

The Japan Aerospace Exploration Agency (JAXA) is conducting research and development on aircraft engine technologies to reduce environmental impact for the Technology Development Project for Clean Engines (TechCLEAN). As a part of the project, combustion technologies have been developed with an aggressive target that is an 80% reduction over the NOx threshold of the International Civil Aviation Organization (ICAO) Committee on Aviation Environmental Protection (CAEP)/4 standard. A staged fuel nozzle with a pilot mixer and a main mixer was developed and tested using a single-sector combustor under the target engine's landing and takeoff (LTO) cycle conditions with a rated output of 40 kN and an overall pressure ratio of 25.8. The test results showed a 77% reduction over the CAEP/4 NOx standard. However, the reduction in smoke at thrust conditions higher than the 30% MTO condition and of CO emission at thrust conditions lower than the 85% MTO condition are necessary. In the present study, an additional fuel burner was designed and tested with the staged fuel nozzle in a single-sector combustor to control emissions. The test results show that the combustor enables an 82% reduction in NOx emissions relative to the ICAO CAEP/4 standard and a drastic reduction in smoke and CO emissions.

Comparison of PM Emissions from a Commercial Jet Engine Burning Conventional, Biomass, and Fischer–Tropsch Fuels

Rising fuel costs, an increasing desire to enhance security of energy supply, and potential environmental benefits have driven research into alternative renewable fuels for commercial aviation applications. This paper reports the results of the first measurements of particulate matter (PM) emissions from a CFM56-7B commercial jet engine burning conventional and alternative biomass- and, Fischer-Tropsch (F-T)-based fuels. PM emissions reductions are observed with all fuels and blends when compared to the emissions from a reference conventional fuel, Jet A1, and are attributed to fuel properties associated with the fuels and blends studied. Although the alternative fuel candidates studied in this campaign offer the potential for large PM emissions reductions, with the exception of the 50% blend of F-T fuel, they do not meet current standards for aviation fuel and thus cannot be considered as certified replacement fuels. Over the ICAO Landing Takeoff Cycle, which is intended to simulate aircraft engine operations that affect local air quality, the overall PM number-based emissions for the 50% blend of F-T fuel were reduced by 34 ± 7%, and the mass-based emissions were reduced by 39 ± 7%.

An inventory of particle and gaseous emissions from large aircraft thrust engine operations at an airport

Published particle number emission factors for aircraft operations remain very sparse and so far such emissions have not been included in the International Civil Aviation Organization (ICAO) databases. This work addresses this gap in knowledge by utilizing recent progress in the quantification of aircraft particle emissions. Annual emissions of particle number (PN), particle mass (PM2.5) and NOx throughout the aircraft landing and takeoff (LTO) cycles and ground running procedures (GRP) are presented for aircraft using Brisbane Airport BNE (domestic and international). The aircraft are grouped according to an airframe based classification system. The resulting data are then used to develop an emissions inventory for large aircraft thrust engine operations on the ground, during LTO cycles and GRP, at the Airport. Annual PN, PM2.5 and NOx emissions from large aircraft operations during LTO cycles and GRP at BNE were 1.98 × 1024 yr−1, 1.35 × 104 kg yr−1 and 8.13 × 105 kg yr−1, respectively. Results showed that LTO cycles contribute more than 97% of these annual emissions at BNE in comparison to GRP related emissions. Analysis of the LTO cycle contribution to the daily emissions showed that the contribution of the climbout mode is considerably higher than for other individual LTO operational modes. Emissions during aircraft departures were significantly higher than those during arrival operations, due to the higher aircraft engine emission rates during takeoff and climbout.

An assessment of Aviation’s contribution to current and future fine particulate matter in the United States

The impacts of aviation emissions on current and future year fine particulate matter (PM 2.5 ) were investigated using the Community Multiscale Air Quality model, accounting for aviation emissions from 99 airports and below 3 km during landing and takeoff (LTO) cycles. Results indicated that current year aviation emissions increased annual average PM 2.5 concentrations by 3.2 ng m −3 (0.05%) in the continental U.S. while projected 2025 aviation emissions increased annual average PM 2.5 by 11.2 ng m −3 (0.20%). Ammonium nitrate aerosol was the largest contributor to the increase in PM 2.5 concentrations, particularly in the future year. Using an indicator of inorganic PM 2.5 change, we attributed ammonium nitrate aerosol contributions in both years to excess free ammonia (8% higher NH 3 and 35% lower NO x emissions from non-aviation sources in 2025 than 2005), and higher aircraft emissions of NO x (which when converted to HNO 3 forms ammonium nitrate aerosol) than SO 2 (a precursor of ammonium sulfate aerosol). Our findings highlight the critical role that non-aviation emissions play in assessing the air quality impacts of aviation emissions in a future year scenario. ► Aircraft LTO emissions in U.S. contribute 3.2 ng/m 3 or 0.05% of annual PM 2.5 in 2005. ► This contribution increases four fold to 0.20% for a future year scenario in 2025. ► Nitrate aerosol was the largest contributor to the changes in PM 2.5. ► Non-aviation emissions combined with aircraft NO x impact future year concentrations. ► Free Ammonia explains the role of non-aviation sources in forming ammonium nitrate.

Effect of chemistry-transport model scale and resolution on population exposure to PM2.5 from aircraft emissions during landing and takeoff

Atmospheric chemistry-transport models are often used to determine the marginal impact of emissions on air quality and public health, but the uncertainties related to modeling assumptions are rarely formally characterized from the perspective of health impact calculations. Aviation emissions are of increasing interest, due to the projected growth in aviation transport coupled with the decreasing emissions from other anthropogenic sources, but the geographic scale and resolution necessary to accurately characterize public health impacts from aviation are unclear, given the unique spatio-temporal pattern of aviation emissions. In this study, we estimate the incremental contribution of commercial aviation emissions during landing and takeoff (LTO) cycles from three U.S. airports – Atlanta’s Hartsfield-Jackson, Chicago’s O’Hare, and Providence’s T.F. Green – to fine particulate matter (PM 2.5 ) levels using the Community Multiscale Air Quality model (CMAQ), a comprehensive chemistry-transport air quality model. To evaluate the significance of model resolution and geographic scale, we ran a one-atmosphere version of CMAQ at 36-, 12-, and 4-km resolutions, and calculated the total population health risks at various distances from each airport. In spite of significant differences in maximum concentrations attributable to aviation emissions, total population health risks over the entire model domain were largely unaffected by model resolution, with a 2% difference in estimated mortality risks between the 36-km and 12-km resolution outputs. Analyses of model scale indicated that a 108 × 108 km domain centered on the airport captured most population exposure for primary components of PM 2.5 , but total public health risks were dominated by populations at greater distances from the airport, given the contribution from secondary ammonium sulfate and nitrate, with 28–35% of health risks occurring more than 300 km from the airports. Our findings provide insight about the model resolution and geographic scales necessary for population risk assessment from LTO emissions, and demonstrate the robustness of risk-based prioritization across multiple grid resolutions. ► Used a CMAQ application to study AQ & health risks from aircraft emissions during LTO. ► Focused on PM 2.5 impacts from 3 U.S. airports – Atlanta, Chicago and Providence. ► Total population health risks unaffected by model resolution: 2% change between grids. ► 28–35% of health risks occur >300-km from airports, due to PM secondary components. ► Relative importance of species depend on choice of max. or total population impacts.

Assessment of Future Aero-engine Designs With Intercooled and Intercooled Recuperated Cores

Reduction in CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction in engine nacelle drag and weight. Conventional turbofan designs, however, that reduce CO2 emissions—such as increased overall pressure ratio designs—can increase the production of NOx emissions. In the present work, funded by the European Framework 6 collaborative project NEW Aero engine Core concepts (NEWAC), an aero-engine multidisciplinary design tool, Techno-economic, Environmental, and Risk Assessment for 2020 (TERA2020), has been utilized to study the potential benefits from introducing heat-exchanged cores in future turbofan engine designs. The tool comprises of various modules covering a wide range of disciplines: engine performance, engine aerodynamic and mechanical design, aircraft design and performance, emissions prediction and environmental impact, engine and airframe noise, as well as production, maintenance and direct operating costs. Fundamental performance differences between heat-exchanged cores and a conventional core are discussed and quantified. Cycle limitations imposed by mechanical considerations, operational limitations and emissions legislation are also discussed. The research work presented in this paper concludes with a full assessment at aircraft system level that reveals the significant potential performance benefits for the intercooled and intercooled recuperated cycles. An intercooled core can be designed for a significantly higher overall pressure ratio and with reduced cooling air requirements, providing a higher thermal efficiency than could otherwise be practically achieved with a conventional core. Variable geometry can be implemented to optimize the use of the intercooler for a given flight mission. An intercooled recuperated core can provide high thermal efficiency at low overall pressure ratio values and also benefit significantly from the introduction of a variable geometry low pressure turbine. The necessity of introducing novel lean-burn combustion technology to reduce NOx emissions at cruise as well as for the landing and take-off cycle, is demonstrated for both heat-exchanged cores and conventional designs. Significant benefits in terms of NOx reduction are predicted from the introduction of a variable geometry low pressure turbine in an intercooled core with lean-burn combustion technology.