PDF methods for turbulent reactive flows

A number of chemical-kinetic problems related to phenomena occurring behind a shock wave surrounding an object flying in the earth atmosphere are discussed, including the nonequilibrium thermochemical relaxation phenomena occurring behind a shock wave surrounding the flying object, problems related to aerobraking maneuver, the radiation phenomena for shock velocities of up to 12 km/sec, and the determination of rate coefficients for ionization reactions and associated electron-impact ionization reactions. Results of experiments are presented in form of graphs and tables, giving data on the reaction rate coefficients for air, the ionization distances, thermodynamic properties behind a shock wave, radiative heat flux calculations, Damkoehler numbers for the ablation-product layer, together with conclusions.

Review of chemical-kinetic problems of future NASA missions, II: Mars entries

Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biomass, and waste, and PM from internal combustion (IC) engines burning gasoline and diesel, are a significant source of primary particles smaller than 2.5 μm (PM2.5) in urban areas. Combustion-generated particles are generally smaller than geologically produced dust and have unique chemical composition and morphology. The fundamental processes affecting formation of combustion PM and the emission characteristics of important applications are reviewed. Particles containing transition metals, ultrafine particles, and soot are emphasized because these types of particles have been studied extensively, and their emissions are controlled by the fuel composition and the oxidant-tem-perature-mixing history from the flame to the stack. There is a need for better integration of the combustion, air pollution control, atmospheric chemistry, and inhalation health research communities. Epidemiology has demonstrated t...

https://www.tandfonline.com/doi/pdf/10.1080/10473289.2000.10464197

Combustion aerosols: factors governing their size and composition and implications to human health.

Review of chemical-kinetic problems of future NASA missions. I: Earth entries

Analysis and abatement of air pollution involve a variety of technical disciplines. Formation of the most prevalent pollutants occurs during the combustion process, a tightly coupled system involving fluid flow, mass and energy transport, and chemical kinetics. Its complexity is exemplified by the fact that, in many respects, the simplest hydrocarbon combustion, the methane-oxygen flame, has been quantitatively modeled only within the last several years. Nonetheless, the development of combustion modifications aimed at minimizing the formation of the unwanted by-products of burning fuels requires an understanding of the combustion process. Fuel may be available in solid, liquid, or gaseous form; it may be mixed with the air ahead of time or only within the combustion chamber; the chamber itself may vary from the piston and cylinder arrangement in an automobile engine to a 10-story-high boiler in the largest power plant; the unwanted byproducts may remain as gases, or they may, upon cooling, form small particles. 

The only effective way to control air pollution is to prevent the release of pollutants at the source. Where pollutants are generated in combustion, modifications to the combustion process itself, for example in the manner in which the fuel and air are mixed, can be quite effective in reducing their formation. Most situations, whether a combustion or an industrial process, however, require some degree of treatment of the exhaust gases before they are released to the atmosphere. Such treatment can involve intimately contacting the effluent gases with liquids or solids capable of selectively removing gaseous pollutants or, in the case of particulate pollutants, directing the effluent flow through a device in which the particles are captured on surfaces. 

The study of the generation and control of air pollutants can be termed air pollution engineering and is the subject of this book. Our goal here is to present a rigorous and fundamental analysis of the production of air pollutants and their control. The book is intended for use at the senior or first-year graduate level in chemical, civil, environmental, and mechanical engineering curricula. We assume that the student has had basic first courses in thermodynamics, fluid mechanics, and heat transfer. The material treated in the book can serve as the subject of either a full-year or a one-term course, depending on the choice of topics covered. 

In the first chapter we introduce the concept of air pollution engineering and summarize those species classified as air pollutants. Chapter 1 also contains four appendices that present certain basic material that will be called upon later in the book. This material includes chemical kinetics, the basic equations of heat and mass transfer, and some elementary ideas from probability and turbulence. 

Chapter 2 is a basic treatment of combustion, including its chemistry and the role of mixing processes and flame structure. Building on the foundation laid in Chapter 2, we present in Chapter 3 a comprehensive analysis of the formation of gaseous pollutants in combustion. Continuing in this vein, Chapter 4 contains a thorough treatment of the internal combustion engine, including its principles of operation and the mechanisms of formation of pollutants therein. Control methods based on combustion modification are discussed in both Chapters 3 and 4. 

Particulate matter (aerosols) constitutes the second major category of air pollutants when classified on the basis of physical state. Chapter 5 is devoted to an introduction to aerosols and principles of aerosol behavior, including the mechanics of particles in flowing fluids, the migration of particles in external force fields, Brownian motion of small particles, size distributions, coagulation, and formation of new particles from the vapor by homogeneous nucleation. Chapter 6 then treats the formation of particles in combustion processes. 

Chapters 7 and 8 present the basic theories of the removal of particulate and gaseous pollutants, respectively, from effluent streams. We cover all the major air pollution control operations, such as gravitational and centrifugal deposition, electrostatic precipitation, filtration, wet scrubbing, gas absorption and adsorption, and chemical reaction methods. Our goal in these two chapters, above all, is to carefully derive the basic equations governing the design of the control methods. Limited attention is given to actual equipment specification, although with the material in Chapters 7 and 8 serving as a basis, one will be able to proceed to design handbooks for such specifications. 

Chapters 2 through 8 treat air pollution engineering from a process-by-process point of view. Chapter 9 views the air pollution control problem for an entire region or airshed. To comply with national ambient air quality standards that prescribe, on the basis of health effects, the maximum atmospheric concentration level to be attained in a region, it is necessary for the relevant governmental authority to specify the degree to which the emissions from each of the sources in the region must be controlled. Thus it is generally necessary to choose among many alternatives that may lead to the same total quantity of emission over the region. Chapter 9 establishes a framework by which an optimal air pollution control plan for an airshed may be determined. In short, we seek the least-cost combination of abatement measures that meets the necessary constraint that the total emissions not exceed those required to meet an ambient air quality standard. 

Once pollutants are released into the atmosphere, they are acted on by a variety of chemical and physical phenomena. The atmospheric chemistry and physics of air pollution is indeed a rich arena, encompassing the disciplines of chemistry, meteorology, fluid mechanics, and aerosol science. As noted above, the subject matter of the present book ends at the stack (or the tailpipe); those readers desiring a treatment of the atmospheric behavior of air pollutants are referred to J. H. Seinfeld, Atmospheric Chemistry and Physics of Air Pollution (Wiley-Interscience, New York, 1986). 

We wish to gratefully acknowledge David Huang, Carol Jones, Sonya Kreidenweis, Ranajit Sahu, and Ken Wolfenbarger for their assistance with calculations in the book.
Finally, to Christina Conti, our secretary and copy editor, who, more than anyone else, kept safe the beauty and precision of language as an effective means of communication, we owe an enormous debt of gratitude. She nurtured this book as her own; through those times when the task seemed unending, she was always there to make the road a little smoother. 

R. C. Flagan
J. H. Seinfeld

Fundamentals of Air Pollution Engineering

A shock‐tube investigation of the dissociation of nitrogen diluted in argon is described which utilizes vacuum‐ultraviolet absorption at 1176 A to monitor the disappearance of molecular nitrogen. Measurements of the dissociation rate coefficients for the process kd(M)N2 + M→2N + M were obtained over the temperature range 8000° to 15 000°K where the collision partner, M, was Ar, N2, and N. The temperature dependence of the individual rate coefficients was found to be the same and was obtained with good precision. The magnitudes of the rate coefficients were generally lower than the currently accepted values obtained in previous shock‐tube investigations, especially the value for kd(N) which, although it was found to be about 10 times greater than kd(Ar), was six times less than two previous measurements. The results of the investigation may be summarized by the following expressions for the dissociation rate coefficients: kd(Ar) = (2.3 ± 0.2) × 10−3T−1.6exp( − 1.132 × 105 / T) cm3sec−1, kd(N2) = (6.2 ± 1.6...

Shock‐Tube Study of Nitrogen Dissociation using Vacuum‐Ultraviolet Light Absorption

https://ntrs.nasa.gov/api/citations/19740018705/downloads/19740018705.pdf

A stochastic model of turbulent mixing with chemical reaction: Nitric oxide formation in a plug-flow burner

The modified phase‐space theory of reaction rates is used to calculate the over‐all recombination and dissociation rate coefficients of nitrogen in a heat bath of argon atoms. Substantial quantitative agreement is obtained between the theoretical predictions and the low‐temperature (90–611°K) “discharge‐flow‐tube” measurements of the recombination rate coefficient and the high‐temperature (8000–15 000°K) “shock‐tube” measurements of the dissociation rate coefficient. The success of the theory in correlating the experimental measurements over such a wide temperature range clearly illustrates the importance of the weak attractive forces between the nitrogen and argon atoms for recombination at low temperatures, the marked reduction in the rates at high temperatures due to nonequilibrium distributions in the vibrational state populations of the molecules, and the major contribution to the over‐all reaction rate coefficients due to reaction progress via the first electronically excited molecular state of nitrogen over the entire temperature range. The working relationships required for applying the modified phase‐space theory to predict the dissociation and recombination rate coefficients of other diatomic molecules in the presence of weakly attracting collision partners, such as argon atoms, are summarized.

Three-Body Recombination and Dissociation of Nitrogen: A Comparison between Theory and Experiment

The modified phase‐space theory of reaction rates has been used to calculate the three‐body recombination and dissociation rate coefficients of hydrogen in the presence of H2, He, Ar, and Xe collision partners. The theoretical predictions, which rely on semiempirically derived interatomic potential information, are shown to be in excellent agreement with the measured rate coefficients over wide temperature ranges.

Gas‐Phase Recombination of Hydrogen. A Comparison between Theory and Experiment

A fluorescence gas analyzer for the measurement of concentrations of NO, SO2, CO, CO2 and other gases that appear in relatively small concentrations in a carrier gas. The carrier gas is subjected to ultraviolet radiation at predetermined wavelengths to effect fluorescence. The spectral wavelengths are chosen for the specific gas of interest. The intensity of the fluorescent radiation from the gas of interest is a measure of the concentration of that gas (NO, SO2, etc.) in the carrier.

Fluorescent gas analyzer with calibration system

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