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Статті в журналах з теми "Aeronautic emissions":
1
Talero, Gabriel, Camilo Bayona-Roa, Giovanny Muñoz, Miguel Galindo, Vladimir Silva, Juan Pava, and Mauricio Lopez. "Experimental Methodology and Facility for the J69-Engine Performance and Emissions Evaluation Using Jet A1 and Biodiesel Blends." Energies 12, no. 23 (November 28, 2019): 4530. http://dx.doi.org/10.3390/en12234530.
Анотація:
Aeronautic transport is a leading energy consumer that strongly contributes to greenhouse gas emissions due to a significant dependency on fossil fuels. Biodiesel, a substitution of conventional fuels, is considered as an alternative fuel for aircrafts and power generation turbine engines. Unfortunately, experimentation has been mostly limited to small scale turbines, and technical challenges remain open regarding operational safety. The current study presents the facility, the instrumentation, and the measured results of experimental tests in a 640 kW full-scale J69-T-25A turbojet engine, operating with blends of Jet A1 and oil palm biodiesel with volume contents from 0% to 10% at different load regimes. Findings are related to the fuel injection system, the engine thrust, and the emissions. The thrust force and the exhaust gas temperature do not expose a significant variation in all the operation regimes with the utilization of up to 10% volume content of biodiesel. A maximum increase of 36% in fuel consumption and 11% in injection pressure are observed at idle operation between B0 and B10. A reduction of the CO and HC emissions is also registered with a maximum variation at the cruise regime (80% Revolutions Per Minute—RPM).
2
Riba, Jordi-Roger, Álvaro Gómez-Pau, Manuel Moreno-Eguilaz, and Santiago Bogarra. "Arc Tracking Control in Insulation Systems for Aeronautic Applications: Challenges, Opportunities, and Research Needs." Sensors 20, no. 6 (March 16, 2020): 1654. http://dx.doi.org/10.3390/s20061654.
Анотація:
Next generation aircrafts will use more electrical power to reduce weight, fuel consumption, system complexity and greenhouse gas emissions. However, new failure modes and challenges arise related to the required voltage increase and consequent rise of electrical stress on wiring insulation materials, thus increasing the risk of electrical arc appearance. This work performs a critical and comprehensive review concerning arc tracking effects in wiring insulation systems, underlying mechanisms, role of materials and possible mitigation strategies, with a special focus on aircraft applications. To this end an evaluation of the scientific and technological state of the art is carried out from the analysis of theses, research articles, technical reports, international standards and white papers. This review paper also reports the limitations of existing insulation materials, standard test methods and mitigation approaches, while identifying the research needs to comply with the future demands of the aircraft industry.
3
Frosina, Emma, Adolfo Senatore, Luka Palumbo, Giuseppe Di Lorenzo, and Ciro Pascarella. "Development of a Lumped Parameter Model for an Aeronautic Hybrid Electric Propulsion System." Aerospace 5, no. 4 (October 4, 2018): 105. http://dx.doi.org/10.3390/aerospace5040105.
Анотація:
This paper describes a case study for applying a hybrid electric propulsion system for general aviation aircraft. The work was performed by a joint team from the Centro Italiano Ricerche Aerospaziali (CIRA) and the Department of Industrial Engineering of the University of Naples Federico II. The use of electric and hybrid electric propulsion for aircraft has gained widespread and significant attention over the past decade. The driver of industry interest has principally been the need to reduce the emissions of combustion engine exhaust products and noise; however, studies have revealed the potential for overall improvement in the energy efficiency and mission flexibility of new aircraft types. The goal of the present study was to demonstrate the feasibility of aeronautic parallel hybrid electric propulsion for light aircraft, varying mission profiles and electric configurations. Through the creation and application of a global model with AMESim® software, in which every aspect of the components chosen by the industrial partners can be represented, some interesting studies were carried out. The numerical model used was more complete and more accurate compared to some others available in the literature. In particular, it was confirmed that, for particular missions, integrating state-of-the-art technologies provides notable advantages for aircraft hybrid electric propulsion for light aircraft.
4
Palma, Giorgio, and Lorenzo Burghignoli. "On the integration of acoustic phase-gradient metasurfaces in aeronautics." International Journal of Aeroacoustics 19, no. 6-8 (September 10, 2020): 294–309. http://dx.doi.org/10.1177/1475472x20954404.
Анотація:
Metamaterials might be one of the breakthrough technologies needed from the aeronautic industry to achieve the more and more challenging targets set by the international authorities, especially about noise emissions. In this article, a theoretical link between Transformation Acoustics and Generalized Snell’s Law, two widely used metamaterial models, is demonstrated analytically and applied to case studies. The relevance of the connection in the aeroacoustic field is discussed along with the consequent computational advantages for numerical simulations. This is exploited to perform a simulation-based design optimization of a phase-graded metasurface acoustic lining of a 2 D duct in presence of flow. Results show promising abilities of the optimized device to modify and control the directivity of the noise emitted from the duct by means of unconventional reflections. The noise reduction in the desired direction is obtained through constructive and destructive interference, with no absorption from the boundaries.
5
Palma, Giorgio, Lorenzo Burghignoli, Francesco Centracchio, and Umberto Iemma. "Innovative Acoustic Treatments of Nacelle Intakes Based on Optimised Metamaterials." Aerospace 8, no. 10 (October 14, 2021): 296. http://dx.doi.org/10.3390/aerospace8100296.
Анотація:
Modern turbofans with high bypass ratios, low blade passage frequencies and short nacelles require continuous development of acoustic linings to achieve the noise reductions expected by the international aviation authorities. Metamaterials and metafluids have been recently proposed as promising technologies for designing innovative acoustic treatments dedicated to reducing aeronautic turbofan noise emissions. In this work, a phase-gradient metasurface treatment is investigated as a way to tackle the noise radiation from an axially symmetric nacelle. This paper aims to study the potential benefits of the mentioned technology, and is not an attempt to design a complete new liner or nacelle. The metasurface is modelled through an equivalent metafluid, and a simulation-based optimisation is used in defining the design parameters. The tonal contribution of the blade passage frequency is considered, and the numerical results with the metafluid optimised on one azimuthal mode at a time show a significant effect in terms of acoustic levels and directivity over an arc of virtual receivers.
6
Talero, Gabriel, Camilo Bayona-Roa, Vladimir Silva, Manuel Mayorga, Juan Pava, and Mauricio Lopez. "Biodiesel substitution in a J69 aeronautic turbine engine: An experimental assessment of the effects on energy efficiency, technical performance and emissions." Sustainable Energy Technologies and Assessments 40 (August 2020): 100746. http://dx.doi.org/10.1016/j.seta.2020.100746.
7
Zaccaria, Valentina, Amare D. Fentaye, Mikael Stenfelt, and Konstantinos G. Kyprianidis. "Probabilistic Model for Aero-Engines Fleet Condition Monitoring." Aerospace 7, no. 6 (May 26, 2020): 66. http://dx.doi.org/10.3390/aerospace7060066.
Анотація:
Since aeronautic transportation is responsible for a rising share of polluting emissions, it is of primary importance to minimize the fuel consumption any time during operations. From this perspective, continuous monitoring of engine performance is essential to implement proper corrective actions and avoid excessive fuel consumption due to engine deterioration. This requires, however, automated systems for diagnostics and decision support, which should be able to handle large amounts of data and ensure reliability in all the multiple conditions the engines of a fleet can be found in. In particular, the proposed solution should be robust to engine-to-engine deviations and different sensors availability scenarios. In this paper, a probabilistic Bayesian network for fault detection and identification is applied to a fleet of engines, simulated by an adaptive performance model. The combination of the performance model and the Bayesian network is also studied and compared to the probabilistic model only. The benefit in the suggested hybrid approach is identified as up to 50% higher accuracy. Sensors unavailability due to manufacturing constraints or sensor faults reduce the accuracy of the physics-based method, whereas the Bayesian model is less affected.
8
Amoroso, Francesco, Angelo De Fenza, Giuseppe Petrone, and Rosario Pecora. "A Sensitivity Analysis on the Influence of the External Constraints on the Dynamic Behaviour of a Low Pollutant Emissions Aircraft Combustor-Rig." Archive of Mechanical Engineering 63, no. 3 (September 1, 2016): 435–54. http://dx.doi.org/10.1515/meceng-2016-0025.
Анотація:
Abstract The need to reduce pollutant emissions leads the engineers to design new aeronautic combustors characterized by lean burn at relatively low temperatures. This requirement can easily cause flame instability phenomena and consequent pressure pulsations which may seriously damage combustor’s structure and/or compromise its fatigue life. Hence the need to study the combustor’s structural dynamics and the interaction between elastic, thermal and acoustic phenomena. Finite element method represent a largely used and fairly reliable tool to address these studies; on the other hand, the idealization process may bring to results quite far from the reality whereas too simplifying assumptions are made. Constraints modelling represent a key-issue for all dynamic FE analyses; a wrong simulation of the constraints may indeed compromise entire analyses although running on very accurate and mesh-refined structural models. In this paper, a probabilistic approach to characterize the influence of external constraints on the modal behaviour of an aircraft combustor-rig is presented. The finite element model validation was performed at first by comparing numerical and experimental results for the free-free condition (no constraints). Once the model was validated, the effect of constraints elasticity on natural frequencies was investigated by means of a probabilistic design simulation (PDS); referring to a specific tool developed in the ANSYS®software, a preliminary statistical analysis was at performed via Monte-Carlo Simulation (MCS) method. The results were then correlated with the experimental ones via Response Surface Method (RSM).
9
Hashmi, Nauman Ehsan, and Atif Manzoor. "International Aeronautical Emission." International Journal of Aviation Technology, Engineering and Management 1, no. 1 (January 2011): 30–36. http://dx.doi.org/10.4018/ijatem.2011010103.
Анотація:
The aviation sector is one the modern innovations in recent times. According to the Federal Aviation Authority (2005, p. 1) in 1903 the world population was estimated to be 1.6 billion, while presently the same number of people use aviation industry as mode of travel. The industry also provides around 28 million jobs and carries 40% of world carriage. But with growing concerns on environmental health, the aviation sector has signifcant impact on the environment. These contributions are in the form of noise and atmospheric emission. In this paper, the authors examine aviation emission and its mitigation straetgy adopted by the European Union (EU).
10
Langat, Rogers K., Emmanuel De Luycker, Arthur Cantarel, and Micky Rakotondrabe. "Integration Technology with Thin Films Co-Fabricated in Laminated Composite Structures for Defect Detection and Damage Monitoring." Micromachines 15, no. 2 (February 15, 2024): 274. http://dx.doi.org/10.3390/mi15020274.
Анотація:
Despite the well-established nature of non-destructive testing (NDT) technologies, autonomous monitoring systems are still in high demand. The solution lies in harnessing the potential of intelligent structures, particularly in industries like aeronautics. Substantial downtime occurs due to routine maintenance, leading to lost revenue when aircraft are grounded for inspection and repairs. This article explores an innovative approach using intelligent materials to enhance condition-based maintenance, ultimately cutting life-cycle costs. The study emphasizes a paradigm shift toward structural health monitoring (SHM), utilizing embedded sensors for real-time monitoring. Active thin film piezoelectric materials are proposed for their integration into composite structures. The work evaluates passive sensing through acoustic emission (AE) signals and active sensing using Lamb wave propagation, presenting amplitude-based and frequency domain approaches for damage detection. A comprehensive signal processing approach is presented, and the damage index and damage size correlation function are introduced to enable continuous monitoring due to their sensitivity to changes in material properties and defect severity. Additionally, finite element modeling and experimental validation are proposed to enhance their understanding and applicability. This research contributes to developing more efficient and cost-effective aircraft maintenance approaches through SHM, addressing the competitive demands of the aeronautic industry.
Дисертації з теми "Aeronautic emissions":
1
Eastham, Sebastian D. (Sebastian David). "Human health impacts of high altitude emissions." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98585.
Анотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 132-159).
Millions of deaths worldwide are attributed annually to exposure degraded surface air quality and UV-induced skin cancer. However, the focus has been on surface emissions, and the contribution of high altitude emissions to these issues is rarely examined. In this thesis, potential links are investigated between high altitude emissions and damages or benefits to human health via photochemical effects. Changes in population exposure to fine particulate matter, ozone and UV-B radiation resulting from current and future high altitude emissions are calculated, applying epidemiologically-derived impact functions to estimate resultant mortality and morbidity. A stratospheric extension is developed for the widely-used tropospheric model GEOS-Chem, which has been shown to accurately model tropospheric conditions and used in simulations of remote and urban pollution. This extended model, the GEOS-Chem UCX, can propagate a stratospheric perturbation through to a tropospheric impact, including shortwave UV fluxes, long-lived species, stratospheric water chemistry and high altitude aerosols. This model is employed to estimate the impacts of reversing 1 K of global warming using stratospheric sulfate aerosol injection. In total, it is projected that 85,000 additional premature mortalities would occur in 2040 due to particulate matter exposure, but that reduced ozone loading would prevent 64,000 mortalities worldwide. Aerosol injection also results in a 5.7% reduction in the global ozone column and a 3.0% increase in surface UV-B, which could cause 3,700 additional melanoma mortalities per year. By comparison, surface air quality and UV-B impacts due to aviation emissions are found to have resulted in 16,000 premature mortalities globally in 2006, of which 450 occurred in North America. Ozone exposure contributes 43% of this total. The increase in tropospheric ozone due to aviation emissions is found to have prevented 390 skin cancer mortalities in 2006. This thesis quantifies the photochemical mechanisms connecting future and proposed high altitude emissions schemes to human health impacts and provides an estimate of mortality and morbidity attributable to aviation and sulfate aerosol injection.
by Sebastian D. Eastham.
Ph. D.
2
Prashanth, Prakash. "Post-combustion emissions control for aero-gas turbine engines." Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/122402.
Анотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018Cataloged from PDF version of thesis.
Includes bibliographical references (pages 47-50).
Aviation NO[subscript x] emissions have an impact on air quality and climate change, where the latter is magnified due to the higher sensitivity of the upper troposphere and lower stratosphere. In the aviation industry, efforts to increase the efficiency of propulsion systems are giving rise to higher overall pressure ratios which results in higher NO[subscript x] emissions due to increased combustion temperatures. This thesis identifies that the trend towards smaller engine cores (gas generators) that are power dense and contribute little to the thrust output presents new opportunities for emissions control that were previously unthinkable when the core exhaust stream contributed significant thrust. This thesis proposes and assesses selective catalytic reduction (SCR), which is a post-combustion emissions control method used in ground-based sources such as power generation and heavy-duty diesel engines, for use in aero-gas turbines.
The SCR system increases aircraft weight and introduces a pressure drop in the core stream. The effects of these are evaluated using representative engine cycle models provided by a major aero-gas turbine manufacturer. This thesis finds that employing an ammonia-based SCR can achieve close to 95% reduction in NO[subscript x] emissions for ~0.4% increase in block fuel burn. The large size of the catalyst needs to be housed in the body of the aircraft and hence would be suitable for future designs where the engine core is also within the fuselage, such as would be possible with turbo-electric or hybrid-electric designs. The performance of the post-combustion emissions control is shown to improve for smaller core engines in new aircraft in the NASA N+3 time-line (2030-2035), suggesting the potential to further decrease the cost of the ~95% NO[subscript x] reduction to below ~0.4% fuel burn.
Using a global chemistry and transport model (GEOS-Chem) this thesis estimates that using ultra-low sulfur (<15 ppm fuel sulfur content) in tandem with post-combustion emissions control results in a ~92% reduction in annual average population exposure to PM₂.₅ and a ~95% reduction in population exposure to ozone. This averts approximately 93% of the air pollution impact of aviation.
by Prakash Prashanth.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
3
Allaire, Douglas L. "A physics-based emissions model for aircraft gas turbine combustors." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35584.
Анотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2006.Includes bibliographical references (p. 103-105).
In this thesis, a physics-based model of an aircraft gas turbine combustor is developed for predicting NO. and CO emissions. The objective of the model is to predict the emissions of current and potential future gas turbine engines within quantified uncertainty bounds for the purpose of assessing design tradeoffs and interdependencies in a policy-making setting. The approach taken is to capture the physical relationships among operating conditions, combustor design parameters, and pollutant emissions. The model is developed using only high-level combustor design parameters and ideal reactors. The predictive capability of the model is assessed by comparing model estimates of NO, and CO emissions from five different industry combustors to certification data. The model developed in this work correctly captures the physical relationships between engine operating conditions, combustor design parameters, and NO. and CO emissions. The NO. estimates are as good as, or better than, the NO. estimates from an established empirical model; and the CO estimates are within the uncertainty in the certification data at most of the important low power operating conditions.
by Douglas L. Allaire.
S.M.
4
Jun, Mina. "Microphysical modeling of ultrane hydrocarbon-containing aerosols in aircraft emissions." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67064.
Анотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 109-115).
Combustion engines emit precursors of ne particulate matter (PM) into the atmosphere. Numerous gaseous species, soot particles, and liquid aerosols in the aircraft exhaust are involved in PM formation, and these very ne, nanometer-size particles potentially have signicant impacts on climate, human health, and air quality. In particular, the organic content of the particles is important to determine physical and chemical properties of PM and consequently their potential impacts on the environment. The main objective of this thesis is to understand the role of organic compounds in PM evolution by developing a microphysical model that incorporates organic compounds into the formation mechanism of binary aqueous aerosols. While binary aerosol models with sulfuric acid and water have been widely studied, the understanding of the effect of organics on the formation and growth of aerosols is still insufficient. This work demonstrates important interactions and competitions in the formation of multi-component aerosols with organic compounds, sulfuric acid, and water in aircraft emissions. Hydrocarbon-containing aerosols have been identied as a major component of ground-level aircraft emission, especially at low power operations. This thesis describes selected surrogates of organic species and introduces estimation techniques for their thermophysical properties. The surrogates of organic species include water-insoluble hydrocarbons and water-soluble oxygenated hydrocarbons. Simulation results suggest that certain hydrocarbon compounds play an important role in the formation of aviation aerosol with interactions with both homogeneous sulfuric acidwater aerosols and soot particles in the organic-rich aircraft plume. Hydrocarbons contribute to the growth of existing homogeneous liquid particles, whereas their contribution to aerosol number density is negligible compared to that of sulfuric acid and water, which largely determine the formation of homogeneous aerosols. Also, low volatility hydrocarbons (e.g., benzopyrene, coronene) are observed to be partitioned into soot particles and induce competition with the uptake of water-soluble species, while light water-soluble oxygenated hydrocarbons enhance the uptake of water and sulfuric acid on soot particles.
by Mina Jun.
Ph.D.
5
Dorbian, Christopher S. (Christopher Salvatore). "Estimating the environmental benefits of aviation fuel and emissions reductions." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59668.
Анотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 99-103).
With commercial aviation continuing to grow and environmental policymaking activity intensifying, it is becoming increasingly necessary to assess the environmental impact of measures that result in changes in aviation fuel bum levels. For estimating air quality and climate impacts, it is important to employ a multi-gas approach that accounts for the effects of all emitted species, not just carbon dioxide (CO₂). The main objective of this thesis is to develop a simplified framework for monetizing the CO₂ and non-CO₂ co-benefits of aviation fuel and emissions reductions. The approach is based on two main pieces, both of which are derived using the Aviation environmental Portfolio Management Tool (APMT). First, the air quality marginal damage cost of a unit of fuel is estimated using an air quality response surface model. Second, a simplified probabilistic impulse response function model for climate is employed to derive a non-CO₂/CO₂ impact ratio that can be multiplied by a social cost of carbon to estimate the additional benefits of fuel bum reductions from aviation beyond those associated with CO2 alone. The sensitivity of the non-CO₂/CO₂ climate ratio to metric choice, scientific assumptions, background scenarios, and other policymaker choices is explored. Notably, it is found that given the large uncertainties in short-lived effects, the choice of metric is not particularly influential on the overall ratio value (that is, similar results-within the range of uncertainty-are found for the different metrics considered). This thesis also validates the use of the climate ratios and air quality marginal damages through two sample applications. The first study explores the impact of various aviation growth scenarios and demonstrates the applicability of this framework to a multi-year analysis. The second study concerns the introduction of an advanced aircraft concept into the present-day aviation fleet and demonstrates the ability of the climate ratios to capture scientific and valuation-based uncertainties. In both cases, the derived ratios and air quality damage costs are found to be a good surrogate for a full impact analysis in APMT, relative to the overall uncertainty in estimating impacts.
by Christopher S. Dorbian.
S.M.
6
Lee, Joosung Joseph 1974. "Historical and future trends in aircraft performance, cost, and emissions." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/8825.
Анотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000.Includes bibliographical references (p. 141-144).
Air travel is continuing to experience the fastest growth among all modes of transport. Increasing total fuel consumption and the potential impacts of aircraft engine emissions on the global atmosphere have motivated the industry, scientific community, and international governments to seek various emissions reduction options. Despite the efforts to understand and mitigate the impacts of aviation emissions, it still remains uncertain whether proposed emissions reduction options are technologically and financially feasible. This thesis is the first of its kind to analyze the relationship between aircraft performance and cost, and assess aviation emissions reduction potential based on analytical and statistical models founded on a database of historical data. Technological and operational influences on aircraft fuel efficiency were first quantified utilizing the Breguet range equation. An aviation system efficiency parameter was defined, which accounts for fuel efficiency and load factor. This parameter was then correlated with direct operating cost through multivariable statistical analysis. Finally, the influence of direct operating cost on aircraft price was statistically determined. By comparing extrapolations of historical trends in aircraft technology and operations with future projections in the open literature, the fuel burn reduction potential for future aircraft systems was estimated. The economic characteristics of future aircraft systems were then determined by utilizing the technology-cost relationship developed in the thesis. Although overall system efficiency is expected to improve at a rate of 1.7% per year, it is not sufficient to counter the projected annual 4 to 6% growth in demand for air transport. Therefore, the impacts of aviation emissions on the global atmosphere are expected to continue to grow. Various policy options for aviation emissions reduction and their potential effectiveness are also discussed.
by Joosung Loseph Lee.
S.M.
7
Lee, Joosung Joseph 1974. "Modeling aviation's global emissions, uncertainty analysis, and applications to policy." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/28917.
Анотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005.Includes bibliographical references (p. 131-134).
(cont.) fuel burn results below 3000 ft. For emissions, the emissions indices were the most influential uncertainties for the variance in model outputs. By employing the model, this thesis examined three policy options for mitigating aviation emissions. More stringent engine certification standards, continuous descent approach procedures, and derated take-off procedures were analyzed. Uncertainties of the model were carefully accounted for in the fuel burn and emissions scenarios of the policy options. The considered policy options achieved roughly 10-30% reductions in NOx emissions. However, HC and CO emissions rather increased due to higher emissions production rate for the CDA and derated take-off. In addition, the NOx emissions reductions in some cases were not statistically significant given the uncertainty in the modeling tool.
Air travel continues to experience fast growth. Although the energy intensity of the air transport system continues to improve, aviation fuel use and emissions of many pollutants have risen. This thesis focuses on developing, assessing and applying a system model to evaluate global aircraft fuel consumption and emissions, and to examine technological and operational measures to mitigate these emissions. The model is capable of computing how much emissions are produced on a flight-by-flight, fleet and global basis and where in the atmosphere the emissions are deposited. These are important questions for aviation environmental policy-making. Model development was followed by a comprehensive uncertainty analysis. It involved comparisons of reported versus modeled results at both the modular and system levels. On average, the aggregate-level composite fuel burn results showed about -6% difference from reported fuel burn data. A statistical analysis showed that this mean shift was a combined contribution of the key uncertainties in aircraft performance and operations. A parametric study followed to rank-order the effects that the key modeling uncertainties had on estimates of fuel burn and emissions. Statistical methods were developed to analyze both the random and systematic errors of the modeling tools. The analyses showed that the uncertainties in engine and aerodynamic performance had the largest impact on system errors, accounting for around 60-70% of the total variance in full-mission fuel burn results. The uncertainties in winds aloft and take-off weight explained another 20-25%. LTO procedures, which consist of engine throttle setting, rate of climb/descent and flight speed, were the most influential uncertainties that drove the variance in
by Joosung Joseph Lee.
Ph.D.
8
Dedoussi, Irene Constantina. "Adjoint sensitivity analysis of the atmospheric impacts of combustion emissions." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120414.
Анотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 127-149).
Combustion emissions impact the environment through chemical and transport processes that span varying temporal and spatial scales. Numerical simulation of the effects of combustion emissions and potential corresponding mitigation approaches is computationally expensive. Atmospheric adjoint modeling enables the calculation of receptor-oriented sensitivities of environmental metrics of interest to emissions, overcoming the numerical cost of conventional modeling. This thesis applies and further develops an existing adjoint of a chemistry-transport model to perform three evaluations, where the high number of inputs (due to the nature of the problem or the associated uncertainty) prevented comprehensive assessment in the past. First, this thesis quantifies the pollution exchange between the US states for seven major anthropogenic combustion emissions sectors: electric power generation, industry, commercial/residential, aviation, as well as road, marine, and rail transportation. This thesis presents the state-level fine particulate matter (PM₂.₅) early death impacts of combustion emissions in the US for 2005, 2011 and 2018 (forecast), and how these are driven by sector, chemical species, and location of emission. Results indicate major shifts in the chemical species and sectors that cause most early deaths, and opportunities for further improving air quality in the US. Second, this thesis quantifies how changes in emissions impact the marginal atmospheric PM₂.₅ response to emissions perturbations. State-level annual adjoint sensitivities of PM₂.₅ population exposure to precursor emissions are compared for the years of 2006 and 2011, and correlated with the magnitude of emissions reduction and the background ammonia mixing ratio. Third, this thesis presents the development and evaluation of the discrete adjoint of the GEOS-Chem unified tropospheric-stratospheric chemistry extension (UCX), which enables the calculation of stratospheric sensitivities and the examination of the entire design space of high altitude emissions impacts. To illustrate its potential, sensitivities of stratospheric ozone to precursor species are calculated. This development expands the span of atmospheric chemistry-transport questions (including inversions) that this open-source model can be used to answer. The assessments performed in this thesis span spatial scales from the regional to the global and demonstrate the ability of this approach to provide information on both bottom-up and top-down mitigation approaches.
by Irene Constantina Dedoussi.
Ph. D.
9
Galligan, Timothy R. "CO₂ emissions reduction potential of aviation biofuels in the US." Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/122397.
Анотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018Cataloged from PDF version of thesis.
Includes bibliographical references (pages 55-60).
Aviation biofuels derived from biomass and wastes have been identified as a means to reduce carbon dioxide (CO₂) emissions from US aviation, but the magnitude of the possible reduction has not been quantified. This scenario-based analysis quantifies the life cycle greenhouse gas (GHG) mitigation potential of aviation biofuels in 2050 within the US. Projected arable land availability, growth in agricultural yields, and the availability of wastes and residues are estimated as a function of future economic and climate patterns, and variability is accounted for. Under a baseline set of assumptions, the use of aviation biofuels results in a maximum reduction of 163 Tg of CO₂ equivalent (CO₂e) in 2050, a 42% reduction in life cycle GHG emissions compared to petroleum-derived jet fuel. Across all scenarios assessed, the reduction in life cycle GHGs ranges from 47.0 to 207 Tg CO₂e (12-53%), requiring the use of fuels derived from wastes, agriculture and forestry residues, and cultivated energy crops. Using only fuels derived from residues and wastes, up to 35% of US jet fuel demand could be met, corresponding to a 28% reduction of CO₂e. The results are most sensitive to assumptions on the distribution of fuel products, and agricultural residue availability.
by Timothy R. Galligan.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
10
Gill, Simaranjit Singh. "Controlling diesel NO_x & PM emissions using fuel components and enhanced aftertreatment techniques : developing the next generation emission control system." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3643/.
Анотація:
The following research thesis focuses on methods of controlling nitrogen oxides (NO_x) and particulate matter (PM) emissions emitted from a low temperature diesel exhaust. This involves studying the influence of hydrogen (H₂) on various aftertreatment devices such as hydrocarbon selective catalytic reduction (HC-SCR) over silver-alumina (Ag-Al₂O₃) catalysts for lean NO_x reduction, platinum diesel oxidation catalysts (DOC) for nitrogen dioxide (NO₂) production and passive regeneration methods for the diesel particulate filter (DPF). H₂ was implemented on-board either through diesel exhaust gas fuel reforming or via the simulation of ammonia (NH₃) dissociation. Both methods showed to be very effective in enhancing the activity of a silver HC-SCR catalyst for the reduction of NO_x with conversions reaching 90% with the aid of an upstream DPF. A combined DOC and catalysed DPF (cDPF) configuration proved promising for passive regeneration in the presence of reformed exhaust gas recirculation (REGR). The addition of H₂ over the DOC led to an improved catalyst light-off temperature and increased rate of oxidation for NO₂ production. Implementing filtered EGR (FEGR) removes the hydrocarbon (HC) and soot recirculation penalty, thus minimising particulate growth which results in a significantly reduced engine-out soot emission during exhaust gas recirculation (EGR) and hence, an improved NO_x/soot ratio. Introducing fuel components which enhance the cetane number and oxygenate the diesel fuel allow better control of the NO_x/soot trade-off with improved soot oxidation properties.
Книги з теми "Aeronautic emissions":
1
Great Britain. Dept. for Transport., ed. UK air passenger demand and CO₂ forecasts. London: Dept. for Transport, 2009.
2
1968-, Klingmüller Angela, Steppler Ulrich 1970-, European Parliament, European Parliament, and European Parliament, eds. EU emissions trading scheme and aviation. Utrecht: Eleven International Publishing, 2010.
3
Geisler, Markus, Stephan Hobe, and Marius Boewe. Luftverkehr und Klimawandel. Berlin: Lit, 2009.
4
United States. Congress. House. Committee on Transportation and Infrastructure. Subcommittee on Aviation. The European Union's emissions trading scheme: A violation of international law : hearing before the Subcommittee on Aviation of the Committee on Transportation and Infrastructure, House of Representatives, One Hundred Twelfth Congress, first session, July 27, 2011. Washington: U.S. G.P.O., 2012.
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National Research Council (U.S.). Committee on Aeronautics Research and Technology for Environmental Compatibility. For greener skies: Reducing environmental impacts of aviation. Washington, D.C: National Academy Press, 2002.
6
JANNAF Exhaust Plume Technology Subcommittee. Meeting. 21st JANNAF Exhaust Plume Technology Subcommittee meeting: Lockheed Missiles and Space Company, Sunnyvale, CA, 19-21 October 1994. Edited by Gannaway Mary T, Johns Hopkins University. Chemical Propulsion Information Agency., and Lockheed Missiles and Space Company. Columbia, MD: Johns Hopkins University, Chemical Propulsion Information Agency, 1994.
7
United States. National Aeronautics and Space Administration., ed. Implementation of ADI-schemes on MIMD parallel computers. San Jose, Calif: MCAT Institute, 1993.
8
United States. National Aeronautics and Space Administration., ed. Implementation of ADI-schemes on MIMD parallel computers. San Jose, Calif: MCAT Institute, 1993.
9
United States. National Aeronautics and Space Administration., ed. Implementation of ADI-schemes on MIMD parallel computers. San Jose, Calif: MCAT Institute, 1993.
10
Organization, International Civil Aviation. ICAO environmental report 2007. Montreal: International Civil Aviation Organization, 2007.
Частини книг з теми "Aeronautic emissions":
1
Aggelis, Dimitrios G., Markus G. R. Sause, Pawel Packo, Rhys Pullin, Steve Grigg, Tomaž Kek, and Yu-Kun Lai. "Acoustic Emission." In Structural Health Monitoring Damage Detection Systems for Aerospace, 175–217. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-72192-3_7.
Анотація:
AbstractAcoustic emission (AE) is one of the most promising methods for structural health monitoring (SHM) of materials and structures. Because of its passive and non-invasive nature, it can be used during the operation of a structure and supply information that cannot be collected in real time through other techniques. It is based on the recording and study of the elastic waves that are excited by irreversible processes, such as crack nucleation and propagation. These signals are sensed by transducers and are transformed into electric waveforms that offer information on the location and the type of the source. This chapter intends to present the basic principles, the equipment, and the recent trends and applications in aeronautics, highlighting the role of AE in modern non-destructive testing and SHM. The literature in the field is vast; therefore, although the included references provide an idea of the basics and the contemporary interest and level of research and practice, they are just a fraction of the total possible list of worthy studies published in the recent years.
2
Schlag, Mareike, Kai Brune, Hauke Brüning, Michael Noeske, Célian Cherrier, Tobias Hanning, Julius Drosten, et al. "Extended Non-destructive Testing for Surface Quality Assessment." In Adhesive Bonding of Aircraft Composite Structures, 119–222. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-319-92810-4_3.
Анотація:
AbstractThis chapter introduces various extended non-destructive testing (ENDT) techniques for surface quality assessment, which are first characterized, then enhanced, and finally applied to assess the level of pre-bond contaminations intentionally applied to carbon fiber reinforced plastic (CFRP) adherends following the procedures described in the previous chapter. Based on two user cases comprising different scenarios that are characteristic of either aeronautical production or repair, the detailed tests conducted on two types of sample geometry, namely flat coupons and scarfed pilot samples with a more complex shape, form the basis for applying the advanced ENDT procedures for the monitoring of realistic and real aircraft parts, as will be described in Chap. 10.1007/978-3-319-92810-4_5. Specifically, the reported investigations were performed to assess the surface quality of first ground and then intentionally contaminated CFRP surfaces using the following ENDT tools: the aerosol wetting test (AWT), optically stimulated electron emission (OSEE), two differently implemented approaches based on electronic noses, laser-induced breakdown spectroscopy (LIBS), Fourier-transform infrared (FTIR) spectroscopy, laser-induced fluorescence (LIF), and laser vibrometry.
3
Renane, Rachid, Rachid Allouche, and Nour Abdelkader. "Effects of Preheating Temperature and Fuel-Air Equivalence Ratio on Pollution Control in Hydro Carbon Combustion." In Mechanical Engineering Technologies and Applications: Volume 2, 84–104. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815124125123020008.
Анотація:
Burning fossil fuels produces a great part of our energy production today and probably it will still do for at least the next few decades. Combustion is encountered in many practical systems such as heaters, power plants, aeronautic engines, buildings, etc. The growing expectations on increasing efficiency and reducing fuel consumption and pollutant emissions make the design of combustion systems much more complex and the science of combustion a rapidly expanding field. Comprehension and analysis of complex physical mechanisms start with the study and control of temperature and species in flame is an important challenge for industrial and environmental issues. We focus our study on a Kerosene, Methane and Gasoil flame simulated with detailed chemistry. The mathematical model is based on the enthalpy conservation between two states, and this model is used with the first law of thermodynamics to define enthalpies of reaction and adiabatic flame temperatures at constant pressure [1, 4]. To reach this objective, we must know the products of complete hydrocarbon combustion and all species of combustion products after dissociation and their molar fractions and equilibrium equations of dissociation reactions. Also, we calculate the elementary equilibrium reactions enthalpy and entropy by using (Bonni Mc Bride et al.) coefficients [2, 3] to compute thermodynamic functions such as specific heat, enthalpy and molar entropy. The obtained system of equations is resolved by Newton Raphson method. Among the obtained results are: To reduce the pollutants (CO2 , CO) and the fuel consumption, the mixture of fuel-air must be lean, therefore, the equivalence ratio must be lower than the unit. According to this study, if the fuel consumption is reduced via the equivalence ratio from 1.1 to 0.95, the combustion temperature remains constant, however, the production of CO will be reduced by 25%.
4
Rodi*, Michael, and Michael Mehling**. "II.Energy." In European Environmental Law, 340–63. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780199545261.003.0010.
Анотація:
Abstract After previous years had seen a number of landmark breakthroughs in climate and energy policy, optimism and elation gave way to a more sober assessment of actual developments in 2006. In January, for instance, climatologists at the National Aeronautics and Space Agency (NASA) reported that the previous year had seen the highest global annual average surface temperature on record, affirming that ‘rapid warming gives urgency to discussions about how to slow green-house gas emissions ‘. A study released in early 2006 by the Tyndall Centre for Climate Change Research even concluded that greenhouse gas emissions must ‘end completely ‘ by the end of the next century if global warming is to be kept within a safe range.
5
Corcau, Jenica-Ileana, Liviu Dinca, and Ciprian-Marius Larco. "Modeling and Simulation of APU Based on PEMFC for More Electric Aircraft." In Aeronautics - New Advances [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.105597.
Анотація:
The current challenge in aviation is to reduce the impact on the environment by reducing fuel consumption and emissions, especially NOX. An open research direction to achieve these desideratums is the realization of new electric power sources based on nonpolluting fuels, a solution being constituted using fuel cells with H2. Reducing the impact on the environment is aimed at both onboard and aerodrome equipment. This paper proposes the simulation and analysis of an auxiliary power source APU based on a fuel cell. The auxiliary power source APU is a hybrid system based on a PEM-type fuel cell, a lithium-ion battery, and their associated converters. The paper presents theoretical models and numerical simulations for each component. The numerical simulation is performed in MATLAB/SimPower Sys. Particular attention is to the converter system that adapts the parameters of the energy sources to the requirements of the electricity consumers on board the MEA-type aircraft. Power management is performed by a controller based on fuzzy logic.
6
Vieira, Carolina Correia, and Rui Castro e Quadros. "Global Commercial Aviation Zero Emissions Target." In Advances in Logistics, Operations, and Management Science, 128–49. IGI Global, 2024. http://dx.doi.org/10.4018/979-8-3693-0908-7.ch008.
Анотація:
These perspectives are primarily reflected on a global scale for 2050 with individual perspectives of the continuation of current technology, advancement in technology and operations, aggressive development of sustainable fuels and a technologically aggressive perspective. Where is considered the average annual percentage of air traffic growth, technology development, improvements in operations and infrastructure, sustainable fuels (SAF – sustainable aviation fuel), and use of offsetting. These scenarios will allow an analysis of the developments studied, with reference to the relationship between CO2 emissions from air transport and the volume of passengers transported, use of new more sustainable models for short and long-distance routes, discrepancies in the development of countries and consequently in achieving the targets. It also enables an overview of the aeronautical industry in the face of various barriers at political, social, economic, and technological level.
7
Deng, Jie, and Nansha Gao. "Periodic Acoustic Black Holes to Mitigate Sound Radiation from Cylindrical Structures." In Acoustic Emission - New Perspectives and Applications. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101959.
Анотація:
Acoustic black holes (ABHs) achieved by progressively diminishing structural thickness have been proved a very efficient approach for wideband vibration reduction, sound suppression, energy harvesting, and wave manipulation. In this chapter, the focus is placed on mitigating the sound emitted from cylindrical shells with embedded ABHs. In the applications of aeronautics, astronautics, and underwater vehicles, cylindrical shells are very common yet the vibroacoustic problems in such structures are very challenging. Even the researches on ABHs for straight beams and flat plates are boosting in recent years, the ABH effect is unclear for curved structures thus it deserves further investigations to push forward their applications. Since cylindrical shells are usually long in, for example, airplanes and rockets, periodic ABHs are designed to alleviate the acoustic emission from them. The Gaussian expansion method (GEM) is employed to recover the vibration field on the cylinder and, based on that, the sound radiation model is developed to determine the emitted sound power level (SWL). The band gaps (BGs) are shown for infinite periodic ABH shells, followed by the vibroacoustic level for a finite periodic shell. Particularly, axial stiffeners are introduced and the influences of their quantity and width are carried out.
8
Baklezos, Anargyros T., and Christos N. Capsalis. "SpaceWire." In Recent Trends on Electromagnetic Environmental Effects for Aeronautics and Space Applications, 39–79. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4879-0.ch002.
Анотація:
SpaceWire is a point-to-point bit shipping protocol for high-speed data communication links and networks providing equipment compatibility and seamless component reusability. It has found great application in many space missions reducing the development cost, offering architectural flexibility, and improving reliability. This chapter delves into the standard describing the SpaceWire, focusing on the lower levels that play a key role in the electromagnetic behavior of the system and concern cable assemblies, shielding, bonding, and grounding. Findings regarding emissions affecting spacecraft components are presented as well as other EMC issues that have an impact on the system performance. Recent developments on the modelling of the cable of the system with a focus on radiated emissions of SpW systems are also presented and discussed.
9
Nikolopoulos, Christos D. "Recent Advances on Measuring and Modeling ELF-Radiated Emissions for Space Applications." In Recent Trends on Electromagnetic Environmental Effects for Aeronautics and Space Applications, 1–38. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4879-0.ch001.
Анотація:
Nowadays, a wide range of space missions accommodate ever-stricter electromagnetic cleanliness requirements arising either from the need for more precise measurements or from the implementation of highly sensitive equipment. Therefore, the establishment of a methodology that ensures the minimization of the electric and/or magnetic field in specific areas inside or outside the spacecraft structure is crucial. Towards this goal, the current chapter proposes that utilizing the results of a process completed during the early design stages of a mission, that is, the measurement and characterization of each implemented device, the desired elimination of the field can be achieved. In particular, the emerged electromagnetic signatures of the units are proven essential for the proposed methodology, which, using a heuristic approach, defines the optimal ordinance of the equipment that leads to system-level electromagnetic field minimization in the volume of interest. The dimensions of the devices and the effect of the conductive surfaces of the spacecraft's hull are also taken into account.
10
Jeevan Danaraj, Edgar. "Electrification for Aero-Engines: A Case Study of Modularization in New Product Development." In Advances in Turbomachinery [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.109006.
Анотація:
Modularization of hybrid-electric propulsion for commercial aircraft is becoming a reality in air transportation. The main intent of an electric architecture is to produce less carbon emissions and advance towards sustainability in the aeronautics industry. Due to regulatory and customer requirements for new technologies aimed at climate change and pollution, the integration of hybrid electric engine design become more challenging. Conceptual modular and integral product architectures are being compared with conventional and new constructions. A Design Structure Matrix (DSM) model is developed to analyze configuration of sub-component and their relationships through interaction between system elements. The DSM model includes product decomposition and cyclic task interdependencies to understand the extent of modularity in the product life cycle. The traditional turbofan engine architecture will be compared with hybrid electric propulsion engine architecture. The analysis indicates that the electric engine configuration constitutes a shift to a more distributed and less modular architecture. The DSM model reported a 19% increase in density of connectivity between components and 58% decrease in terms of structural complexity. The significance of these changes demonstrates that the more distributed architecture of the fully electric engine architecture requires less effort in system integration than the geared traditional turbofan architecture.
Тези доповідей конференцій з теми "Aeronautic emissions":
1
Trancossi, Michele. "Design of a Cogeneration Hybrid Propulsion System for Commuter Aircrafts With Thermal Recovery." In ASME 2015 9th International Conference on Energy Sustainability collocated with the ASME 2015 Power Conference, the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/es2015-49815.
Анотація:
This paper approaches the argument of cogeneration in aircraft propulsion. It presents an effective design of a cogeneration system with thrust augmentation by heat recovery for aeronautic propulsion which can be installed inside an electrical ducted fan unit. The system optimization is based on constructal law. Energy comparison against potential competitors is produced together with an analysis in terms of GHG emissions.
2
Bulzan, Dan, Bruce Anderson, Changlie Wey, Robert Howard, Edward Winstead, Andreas Beyersdorf, Edwin Corporan, et al. "Gaseous and Particulate Emissions Results of the NASA Alternative Aviation Fuel Experiment (AAFEX)." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-23524.
Анотація:
The Aircraft Alternative Fuels Emissions experiment (AAFEX) was conducted at National Aeronautic and Space Administration (NASA) Dryden Flight Research Center (DFRC) Aircraft Operations Facility (DAOF) in Palmdale, California, during January and February 2009. The purpose was to systematically investigate the effect of alternative fuels on both gas-phase and particle emissions from a CFM56-2C1 engine on NASA’s DC-8 aircraft parked on the ground as functions of engine power, fuel composition, and exhaust plume age. Emissions parameters were measured at 6 engine power settings, ranging from idle to maximum thrust, in samples collected at 1, 30, and 145 meters (m) downstream of the exhaust plane as the aircraft burned three pure fuels and two fuel blends. The fuels included JP-8, two fuels produced using the Fischer-Tropsch process and 50/50 blends by volume of the F-T fuels with JP-8. The 1 m sampling rakes contained multiple gas and particle inlet probes and could also be traversed in order to measure the spatial variation of emissions across the engine exhaust plane. The #2 inboard engine on the left side always burned JP-8 while the #3 inboard right side engine was fueled with the various fuels and fuel blends. In addition, emissions from the Auxiliary Power Unit (APU) were also evaluated with both JP-8 and one pure F-T fuel. Both gaseous and particulate emissions are presented. Results show that the synthetic fuels reduced pollutant emissions while having relatively little effect on engine operation or performance.
3
Ruan, Jiangheng L., Axel Vincent-Randonnier, Guillaume Pilla, and Cornelia Irimiea. "Development of Innovative Low NOx Hydrogen-Fueled Burner for Aeronautic Applications." In ASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/gt2023-100453.
Анотація:
Abstract Large eddy simulations (LES) were performed to develop an innovative hydrogen-fueled burner for aeronautic applications. Hydrogen is a much cleaner fuel than classic jet fuels (hydrocarbons) since its combustion with air only produces water without any carbon compounds (soot particles, volatile organic compounds, carbon monoxide or carbon dioxide). Nevertheless, at high temperatures (i.e. over about 1800 K), nitrogen and oxygen in the air combine to produce nitrogen oxides (NOx). Low-NOx combustion then implies to achieve lean premixed conditions. Unfortunately, due to the high laminar flame speed and very lean limit of extinction of H2-air flames, hydrogen combustion is prone to flashback, thus implying to design fast mixing injectors. Lean Direct Injection (LDI) and Micromix concepts have been proposed to boost the mixing between hydrogen and air. LDI relies on rapid and uniform mixing to get a lean premixed H2-air mixture before combustion occurs, whereas Micromix concept divides the burner into several small elementary burners. In the current paper, we present the results of numerical simulations performed with an original design of a swirled injector designed to achieve stable H2-air combustion in lean-premixed conditions. However, the sole premixed injection is insufficient to stabilize combustion from idle to take-off conditions. To fix this issue, a pilot injection of fuel (i.e. generating a non-premixed flame) has been added to sustain combustion in a wide range of operating conditions. The flame produced with this burner has been investigated numerically for three operating conditions of a turboshaft engine: takeoff, cruise and idle conditions. Simulations were carried out with a 9 species and 21 steps chemical mechanism for H2-air, which was then modified to take into account the NOx formation using the Zeldovich model. Comparisons between simulations using Quasi-Laminar Model (QLM) and Thickened Flame Model (TFM) were performed. Both models lead to stable combustion for any flight conditions, with NOx emissions at about a hundred times lower than the measured level with an engine of equivalent thrust operated with kerosene Jet A-1. Finally, experiments were achieved on a semi-industrial scale test rig operated at the same conditions than CFD simulations. Thanks to the combustor optical accesses and the gas sampling probe inside the chamber, images of the flame and NOx measurements could be obtained, showing a satisfactory agreement with simulations.
4
Duchaine, Patrick, Quentin Bouyssou, Stéphane Pascaud, Gorka Exilard, and Christophe Viguier. "Soot Emission Optimization of a Helicopter Engine: From Injector Design to Engine Tests Validation." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16100.
Анотація:
Abstract Even though no regulation currently exists on helicopter gas turbines, soot production in aeronautic engines is of paramount importance to comply with future rules, as well as to offer environmental-friendly products on the market. Thus, design modifications of the combustion liner and fuel injectors are one way to explore in order to reduce soot emission levels of existing combustors. These design changes are driven both by fundamental knowledge of soot production mechanisms and by advanced combustion and pollutants modelling. The major difficulty is to reduce soot emissions while not deteriorating other combustion performances: NOx and CO emissions, lean blow-off limits and service lifetime. The objective of the present study is to optimize fuel injectors of a recent Safran Helicopter Engines research combustor. The injector design modifications are driven by one main guideline: reducing soot emissions can be achieved by lowering the equivalence ratio downstream of the injector. Detailed designs are achieved thanks to advanced RANS injector and LES combustion computations. Then, in order to mitigate main identified risks — management of soot emissions and lean blow-off limits — engine tests were performed very early in the demonstration process. A combustor is successively equipped with one standard and two modified geometries of fuel injectors on an engine test bench. Experimental results show that the two modified injector geometries reduce smoke numbers by a factor of respectively 2 and 9 and slightly deteriorates lean blow-off limits. These measurements are also compared to CFD computations. Leung et al. model (Combust Flame 1991), relying on phenomenological descriptions of soot formation combined with a LES computation of the combustor, well predicts a significant decrease in smoke level, even if it does not perfectly match engine data. Concerning lean blow-off limits, LES modelling predict a decrease in lean blow-off limits, which do not agree qualitatively with engine test results. As a conclusion, this study identifies a design driving factor for soot reduction, with possibly acceptable impacts on other combustion performances like lean blow-off limits.
5
Kritikos, Kosmas, Emidio Giordano, Anestis I. Kalfas, and Nicolas Tantot. "Prediction of Certification Noise Levels Generated by Contra-Rotating Open Rotor Engines." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69232.
Анотація:
The tendency for environmentally friendlier aeronautic engines, led to the re-examination of the contra rotating open rotor (CROR) as a more efficient and less polluting propulsion system, thanks to its noticeably high propulsive efficiency. The geometrical and operational characteristics of these contra rotating propellers are examined in order to optimize the noise emissions, given the challenging regulation context for such an unducted concept. For this research, computational techniques have been used to develop a numerical model for prediction of noise levels generated by CRORs propellers. An extended database of unsteady CFD simulations, generated with innovative methods, namely a non-linear harmonic flow solver and an acoustic propagation model based on the Ffowcs Williams–Hawkings approach, have been used to assess the noise spectra measured in the certification points. Sound pressure levels and frequencies have been afterwards converted into EPN levels along the aircraft flight path, according to the ICAO regulation. The whole procedure has been applied to 102 different cases to establish the influence of several independent parameters on noise emissions. A surface response model has finally been developed, providing an easy tool of fast utilization to be implemented in optimization platforms.
6
Leparoux, Julien, Renaud Lecourt, and Olivier Penanhoat. "Effect of Aromatics in Jet Fuels on Spray Characteristics Downstream of an Aeronautical Pressure Swirl Atomizer." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56565.
Анотація:
Standard aeronautic fuels have a lower limit of aromatics of 8% (by volume) with about 18% for regular Jet A1. It has been shown that aromatics contained in Jet fuel have an impact on the fine particle emissions. In order to reduce these emissions, alternative fuels with lower aromatic content have been identified as a promising solution. Change Jet fuel composition can have several effects on spray and combustion behaviors, among others: atomization process, droplet evaporation, flame structure, pollutant and particle emissions. Then, it is necessary to evaluate the impact of this change on gas turbine performance and operability. The present study is focused on the spray behavior investigation with different aromatic content. Four Jet fuels are investigated including conventional Jet A1 kerosene, drop-in fuel with a mixture of half conventional Jet fuel and synthetic paraffinic kerosene (SPK), SPK with 8% of aromatics and pure SPK. The tests are performed at atmospheric conditions on the MERCATO testbed located at ONERA (FR). Phase Doppler Anemometry (PDA) measurements are carried out for the four fuels on an injection system composed of a pressure swirl atomizer and an air swirler. In this paper, a spray analysis of liquid velocity and droplet diameter measurements is described and linked to the variations of fuel properties. In the range of parameters covered by the four different fuels, it is shown that the spray behavior of each fuel is similar to the conventional Jet A1.
7
Caggese, S. "A parametric model for thermal management system for more electric and hybrid aircraft." In Aeronautics and Astronautics. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902813-17.
Анотація:
Abstract. In the last decade, the hybrid and electric propulsive systems have been gaining increasing interest to cut down greenhouse gas emissions and thus reduce the environment impact of the aerospace sector. The paper reports the development of a parametric model to design and simulate the Thermal Management System (TMS) of an hybrid electric regional aircraft. Considering the need for a compact design and avoiding the generation of additional drag, a liquid-to-liquid offset strip fin surface heat exchanger is selected. Analysis and modelling of the system are performed for both traditional and innovative coolant, namely, as nanofluids. Five different thermal load conditions are analyzed, which correspond to five different levels of hybridization defined in terms of reduction of CO2 emission. The most demanding one entails a reduction up to 50% of CO2 and a thermal load of 67.2 kW to be dissipated. The paper also aims to investigate the most challenging conditions for TMS design and whether the suitability of nanofluids as superior heat carriers. In fact, using nanofluids it is possible to reduce the size of heat exchanger, thanks to the higher thermal conductivity compared to conventional coolant.
8
Tong, Michael T. "A Probabilistic Risk-Based Approach to Assess NASA Aeronautics Technologies." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-91007.
Анотація:
NASA’s aeronautics research program invests in air-transportation technologies to protect the environment, makes air travel more accessible and affordable for Americans, enables exploration through new aerospace missions, and augments national security. The program will address critical public needs related to reduction of aircraft noise and emissions, and enable new science missions. In this paper, a probabilistic risk-based approach is presented to provide guidance for developing a robust technology portfolio, and to prioritize the most promising technologies required to achieve aeronautics program goals. An assessment of subsonic aircraft emission-reduction technologies is performed to demonstrate how the approach can be used to guide technology investment in the context of limited NASA funding for aeronautics technology research.
9
Reddy, Dhanireddy R., and Chi-Ming Lee. "An Overview of Low-Emission Combustion Research at NASA Glenn." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56100.
Анотація:
An overview of research efforts at NASA Glenn Research Center (GRC) in low-emission combustion technology that have made a significant impact on the nitrogen oxides (NOx) emission reduction in aircraft propulsion is presented. The technology advancements and their impact on aircraft emissions are discussed in the context of NASA’s Aeronautics Research Mission Directorate (ARMD) high-level goals in fuel burn, noise and emission reductions. The highlights of the research presented here show how the past and current efforts laid the foundation for the engines that are flying today as well as how the continued technology advancements will significantly influence the next generation of aviation propulsion system designs.
10
Richiardi, G. "Low-boom supersonic business jet: aerodynamic analysis and mission simulation towards a CO2 emission standard." In Aeronautics and Astronautics. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902813-27.
Анотація:
Abstract. This study aims at investigating the aerodynamic characteristics and mission performance of a supersonic business jet at a conceptual design stage. Moreover, the environmental impact of such concept is analyzed to support the development of a potential CO2 emissions standard for supersonic transport aircraft. The case study considered for the analysis is a supersonic business jet.