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Study Of Particulate Matter Formation And Evolution In Near Field Aircraft Plumes Using A One Dimensional Microphysical Model
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Book Synopsis Study of Particulate Matter Formation and Evolution in Near-field Aircraft Plumes Using a One-dimensional Microphysical Model by : Jianye Zhang (S.M.)
Download or read book Study of Particulate Matter Formation and Evolution in Near-field Aircraft Plumes Using a One-dimensional Microphysical Model written by Jianye Zhang (S.M.) and published by . This book was released on 2007 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental concerns have led to a growing effort to investigate and characterize the particulate matter (PM) emissions from aircraft engines. This thesis presents a one-dimensional microphysics and chemical kinetics model that is used to study the formation and evolution of particulate matter in near field aircraft plumes at ground level. The initial exhaust properties were obtained from engine data and plume mixing profiles were generated using FLUENT®. The initial gas species concentrations were estimated based on a two-step constrained equilibrium process. Parametric studies of the effects of ambient temperature, ambient relative humidity, engine operating conditions and engine design parameters on the aerosol formation were investigated using the one dimensional model following a centerline trajectory up to lkm downstream of the engine exit plane. PM formation and evolution characteristics along trajectories from several radial locations were also investigated and compared to the results from the centerline study. The results from this study show that binary homogeneous H2SO4-H20 nucleation strongly depends on ambient conditions such as ambient temperature and relative humidity whereas the condensational growth of soot particles is most dependent on engine power settings.
Book Synopsis Modeling of Particulate Matter Creation and Evolution in Aircraft Engines, Plumes and Particle Sampling Systems by : Pierre Max Dakhel
Download or read book Modeling of Particulate Matter Creation and Evolution in Aircraft Engines, Plumes and Particle Sampling Systems written by Pierre Max Dakhel and published by . This book was released on 2005 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Recommendations to improve the measuring techniques at ground level include lowering the residence time of gas samples inside the sampling system to avoid too large a modification of the flow microphysical characteristics before it reaches the measuring instruments, and careful monitoring of the temperature of the sample throughout the probe and sampling line.
Book Synopsis Numerical Modeling of Chemistry, Turbulent Mixing and Aerosol Dynamics in Near-field Aircraft Plumes by : Zheng Wang
Download or read book Numerical Modeling of Chemistry, Turbulent Mixing and Aerosol Dynamics in Near-field Aircraft Plumes written by Zheng Wang and published by . This book was released on 1998 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling Aircraft Contrails and Emission Plumes for Climate Impacts by : Alexander Dean Naiman
Download or read book Modeling Aircraft Contrails and Emission Plumes for Climate Impacts written by Alexander Dean Naiman and published by Stanford University. This book was released on 2011 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aircraft emissions lead to contrails and change cloud coverage in the upper troposphere/lower stratosphere, but their quantitative impact on climate is highly uncertain. As environmental policy turns toward regulating anthropogenic climate change components, it will be necessary to improve quantification of the climate impacts of aviation. Toward this end, we present two models of aircraft emissions. The first model is a large eddy simulation (LES) with three-dimensional, eddy-resolving flow physics and ice deposition/sublimation microphysics. Modeled ice properties, cloud optical depths, and contrail width growth rates are consistent with observational field studies. A series of sensitivity cases shows the effect of various parameters over twenty minutes of simulation time. The analysis focuses on properties such as contrail optical depth and cross-sectional width that are relevant to climate impacts. Vertical wind shear is found to have the strongest effect on these properties through the kinematic spreading of the contrail. In cases with no shear, optical depth is most sensitive to aircraft type and ambient humidity. One model parameter, the effective emission index of ice crystals, is also found to affect optical depth. A subset of the LES cases is run for two hours of simulation time to approach the scale of dynamical time steps modeled by global climate simulations. These cases use more realistic ice microphysics, including sedimentation, and forced ambient turbulence, both of which are processes that control contrail development at late times. The second model is a simple, low cost parameterization of aircraft plume dynamics, intended to be used as a subgrid plume model (SPM) within large scale atmospheric simulations. The SPM provides basic plume cross-section time advancement that has been used as a dilution model within a coupled global atmosphere-ocean climate simulation to study the effects of aviation on air quality and climate. Comparison to the twenty-minute and two-hour LES results demonstrates that the SPM captures important plume development characteristics under the effect of vertical shear and atmospheric turbulence.
Book Synopsis Microphysical Modeling of Ultrafine Hydrocarbon-containing Aerosols in Aircraft Emissions by : Mina Jun
Download or read book Microphysical Modeling of Ultrafine Hydrocarbon-containing Aerosols in Aircraft Emissions written by Mina Jun and published by . This book was released on 2011 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Spring Meeting by : American Geophysical Union. Meeting
Download or read book Spring Meeting written by American Geophysical Union. Meeting and published by . This book was released on 2000 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781724301871 Total Pages :216 pages Book Rating :4.3/5 (18 download)
Book Synopsis Modeling Macro- And Micro-Scale Turbulent Mixing and Chemistry in Engine Exhaust Plumes by : National Aeronautics and Space Administration (NASA)
Download or read book Modeling Macro- And Micro-Scale Turbulent Mixing and Chemistry in Engine Exhaust Plumes written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-27 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation of turbulent mixing and chemical processes in the near-field plume and plume-vortex regimes has been successfully carried out recently using a reduced gas phase kinetics mechanism which substantially decreased the computational cost. A detailed mechanism including gas phase HOx, NOx, and SOx chemistry between the aircraft exhaust and the ambient air in near-field aircraft plumes is compiled. A reduced mechanism capturing the major chemical pathways is developed. Predictions by the reduced mechanism are found to be in good agreement with those by the detailed mechanism. With the reduced chemistry, the computer CPU time is saved by a factor of more than 3.5 for the near-field plume modeling. Distributions of major chemical species are obtained and analyzed. The computed sensitivities of major species with respect to reaction step are deduced for identification of the dominant gas phase kinetic reaction pathways in the jet plume. Both the near field plume and the plume-vortex regimes were investigated using advanced mixing models. In the near field, a stand-alone mixing model was used to investigate the impact of turbulent mixing on the micro- and macro-scale mixing processes using a reduced reaction kinetics model. The plume-vortex regime was simulated using a large-eddy simulation model. Vortex plume behind Boeing 737 and 747 aircraft was simulated along with relevant kinetics. Many features of the computed flow field show reasonable agreement with data. The entrainment of the engine plumes into the wing tip vortices and also the partial detrainment of the plume were numerically captured. The impact of fluid mechanics on the chemical processes was also studied. Results show that there are significant differences between spatial and temporal simulations especially in the predicted SO3 concentrations. This has important implications for the prediction of sulfuric acid aerosols in the wake and may partly explain the discrepancy between past numerical studies ...
Book Synopsis Micro-physical Modeling of Aircraft Exhaust Plumes and Condensation Trails by : Thibaud M. Fritz
Download or read book Micro-physical Modeling of Aircraft Exhaust Plumes and Condensation Trails written by Thibaud M. Fritz and published by . This book was released on 2018 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to quantitatively assess the environmental impacts of air transport operations is necessary to estimate their current and future impacts on the environment. Emissions from aircraft engines are a significant contributor to atmospheric NOx driving climate change, air quality impacts and other environmental concerns. To quantify these effects, global chemistry-transport models are frequently used. However, such models assume homogeneous and instant dilution into large-scale grid cells and therefore neglect micro-physical processes, such as contrail formation, occurring in aircraft wakes. This assumption leads to inaccurate estimates of NOy partitioning, and thus, an over-prediction of ozone production. To account for non-linear plume processes, a Lagrangian aircraft plume model has been implemented. It includes a unified tropospheric-stratospheric chemical mechanism that incorporates heterogeneous chemistry. Micro-physical processes are considered throughout the entire plume lifetime. The dynamics of the plume are solved simultaneously using an operator splitting method. The plume model is used to quantify how the in-plume chemical composition is affected in response to various environmental conditions and different engine and/or fuel characteristics. Results demonstrate that an instant dilution model overestimates ozone production and accelerates conversion of nitrogen oxides compared to the plume model. Sensitivities to the NOx emission index have been derived and the dependence of the plume treatment on the background atmosphere mixing ratios, pressure and latitude has been investigated for a future regional scale assessment of the aviation sector. The cumulative impact of successive flights has been estimated. Contrail micro-physical and chemical properties have been computed under different scenarios. This aircraft plume model has been extensively validated and enables an in-depth assessment of the impact of one or multiple flights on local atmospheric conditions.
Book Synopsis Particle Formation and Growth in Power Plant Plumes: Field observations and theoretical studies of the evolution of particles in the plumes from coal-fired electric power plants by :
Download or read book Particle Formation and Growth in Power Plant Plumes: Field observations and theoretical studies of the evolution of particles in the plumes from coal-fired electric power plants written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Microphysical Mechanism of New Particle Formation Associated with Asian Pollution Plumes During Trace P by : Sangil Lee
Download or read book Microphysical Mechanism of New Particle Formation Associated with Asian Pollution Plumes During Trace P written by Sangil Lee and published by . This book was released on 2002 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling Aircraft Contrails and Emission Plumes for Climate Impacts by : Alexander Dean Naiman
Download or read book Modeling Aircraft Contrails and Emission Plumes for Climate Impacts written by Alexander Dean Naiman and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Aircraft emissions lead to contrails and change cloud coverage in the upper troposphere/lower stratosphere, but their quantitative impact on climate is highly uncertain. As environmental policy turns toward regulating anthropogenic climate change components, it will be necessary to improve quantification of the climate impacts of aviation. Toward this end, we present two models of aircraft emissions. The first model is a large eddy simulation (LES) with three-dimensional, eddy-resolving flow physics and ice deposition/sublimation microphysics. Modeled ice properties, cloud optical depths, and contrail width growth rates are consistent with observational field studies. A series of sensitivity cases shows the effect of various parameters over twenty minutes of simulation time. The analysis focuses on properties such as contrail optical depth and cross-sectional width that are relevant to climate impacts. Vertical wind shear is found to have the strongest effect on these properties through the kinematic spreading of the contrail. In cases with no shear, optical depth is most sensitive to aircraft type and ambient humidity. One model parameter, the effective emission index of ice crystals, is also found to affect optical depth. A subset of the LES cases is run for two hours of simulation time to approach the scale of dynamical time steps modeled by global climate simulations. These cases use more realistic ice microphysics, including sedimentation, and forced ambient turbulence, both of which are processes that control contrail development at late times. The second model is a simple, low cost parameterization of aircraft plume dynamics, intended to be used as a subgrid plume model (SPM) within large scale atmospheric simulations. The SPM provides basic plume cross-section time advancement that has been used as a dilution model within a coupled global atmosphere-ocean climate simulation to study the effects of aviation on air quality and climate. Comparison to the twenty-minute and two-hour LES results demonstrates that the SPM captures important plume development characteristics under the effect of vertical shear and atmospheric turbulence.
Book Synopsis Soot Formation in Combustion by : Henning Bockhorn
Download or read book Soot Formation in Combustion written by Henning Bockhorn and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot Formation in Combustion represents an up-to-date overview. The contributions trace back to the 1991 Heidelberg symposium entitled "Mechanism and Models of Soot Formation" and have all been reedited by Prof. Bockhorn in close contact with the original authors. The book gives an easy introduction to the field for newcomers, and provides detailed treatments for the specialists. The following list of contents illustrates the topics under review:
Book Synopsis A Study of Rocket Exhaust Plumes Using a One-dimensional Flow Model with Nonequilibrium Chemistry by : Edwin Cash Word
Download or read book A Study of Rocket Exhaust Plumes Using a One-dimensional Flow Model with Nonequilibrium Chemistry written by Edwin Cash Word and published by . This book was released on 1977 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987 with total page 1126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Book Synopsis Numerical Study of the Near-Field Unsteady Dynamics of Planar Plumes by : M. C. Soteriou
Download or read book Numerical Study of the Near-Field Unsteady Dynamics of Planar Plumes written by M. C. Soteriou and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Strategies for Stratospheric Research by : Peter Fabian
Download or read book Strategies for Stratospheric Research written by Peter Fabian and published by . This book was released on 1995 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt:
