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Development Of On-The-Fly Quasi-Steady State Approximation For Chemical Kinetics In Cfd, Abhinav Balamurugan

Doctoral Dissertations and Master's Theses

This study analyzes the feasibility of On-The-Fly Quasi-Steady-State Approximation (OTF-QSSA) application for solving chemical kinetics within Computational Fluid Dynamics (CFD) simulations, aiming to reduce the computational demand of detailed mechanisms. An algorithm that dynamically identifies and designates Quasi-Steady-State (QSS) species at specific grid locations and instances during the simulation was developed. With this information, our method pseudo-delays the advancement of concentrations for these QSS species—effectively setting their rate of concentration change to zero for a set number iteration before updating using the detailed mechanism and thereby omitting the computationally intensive processes typically required for their calculation during those skipped iteration. …

Tracking The Reaction Networks Of Criegee Intermediates Formed In The Ozone-Assisted Oxidation Reactions Of C5 Acyclic And Endocyclic Alkenes, Arden M. Floyd

Honors Undergraduate Theses

Uni- and bi-molecular reactions involving Criegee intermediates (CIs), characteristic to alkene-ozone reactions, play an important role in synthetic organic, atmospheric, and combustion chemistry. However, difficulty in detecting key intermediates has prevented a thorough understanding of the details of the ozonolysis mechanism. To gain new insights into how alkene structure affects the CI network, the ozone assisted oxidation reactions of trans-2-pentene and cyclopentene are investigated between 320 K and 760 K in an atmospheric pressure jet stirred reactor (JSR). Molecular-beam mass spectrometry in conjunction with single photon tunable synchrotron VUV radiation is used to identify elusive intermediates by means of …

Acetylacetone Oxidation At Room Temperature: A Multiplexed Photoionization Mass Spectrometric Investigation, Study Of The Russell Intermediates In Gas Phase Reactions, And The Investigation Of Oxidation Reaction Products Of Ethanol At Room Temperature, Sara Gallarati

Master's Theses

This thesis presents the combustion study of acetyl acetone using synchrotron radiation coupled with multiplexed photoionization mass spectrometry at 298 K. The experiments were performed at the Chemical Dynamics Beamline 9.0.2 at the Advanced Light Source of the Lawrence Berkeley National Laboratory. The reaction of acetyl acetone with chlorine (Cl) radicals was analyzed based on their photoionization spectra and reaction kinetic profiles.

Additionally, a study of the Russell intermediate has been performed. Previous to experimentation at the Advanced Light Source, computational analysis has been investigated to evaluate compounds that could possibly lead to the formation of a stable species. The …

Infiltration-Controlled Combustion Of Lithium And Magnesium Powders And Reactions Of Lithium With Oxygen And Carbon Dioxide, Kevin Samuel Estala Rodriguez

Open Access Theses & Dissertations

Chemical heat integrated power systems are of great interest for space missions where solar energy, nuclear energy, and batteries are not available or are not practical to use. A new concept of a power system is a metal combustor coupled with a chemical oxygen generator, where the generated oxygen infiltrates through the metal powder or combustion products. The combustion of lithium and magnesium powders under these conditions has not been studied yet. The present work investigates combustion of magnesium powder and stabilized lithium metal powder (SLMP) ignited by a laser inside a closed chamber filled with O2 or CO2. It …

Characterization Of A Flex-Fuel Oxy-Combustion System Through Experimental Investigation And Computational Modeling, Md Mohieminul I. Khan

Open Access Theses & Dissertations

Oxy-fuel combustion has the potential to offer high thermal efficiency and lower pollutants emission compared to other existing combustion technologies. More than 63% of the worldâ??s electricity is produced by fossil fuel combustion which also is the major reason for greenhouse gas emissions. Oxy combustion offers a solution to it. Oxy combustion uses pure oxygen as an oxidizer instead of air which eliminates the NOx and SOx products from the exhaust. In oxy-combustion flue gas mainly consists of CO2 and water vapor. Furthermore, combustion in presence of pure oxygen results in higher flame temperature and hence promises higher thermal efficiency. …

Direct Simulation And Reduced-Order Modeling Of Premixed Flame Response To Acoustic Modulation, Zheng Qiao

Theses and Dissertations

This dissertation introduces a general, predictive and cost-efficient reduced-order modeling (ROM) technique for characterization of flame response under acoustic modulation. The model is built upon the kinematic flame model–G-equation to describe the flame topology and dynamics, and the novelties of the ROM lie in i) a procedure to create the compatible base flow that can reproduce the correct flame geometry and ii) the use of a physically-consistent acoustic modulation field for the characterization of flame response. This ROM addresses the significant limitations of the classical kinematic model, which is only applicable to simple flame configurations and relies on ad-hoc models …

The Impact Of Burning On The Structure And Mineral Composition Of Bat Guano, Joyce Lundberg, Donald A. Mcfarlane

International Journal of Speleology

Here we addressed the question of whether burning of guano produces a characteristic suite of morphological changes and/or unique mineralogical products. The changes observed in our experimental burning of guano (both fresh and decayed) included colour change (blackening), grain size and morphological change (grain size generally reduced, morphology rendered generally less distinct), alteration of minerals by dehydration (e.g., gypsum to anhydrite, brushite to whitlockite), and production of new minerals or compounds (e.g., augelite, bayerite, giniite, graphite, oldhamite, strontium apatite, tridymite). The key morphological feature we found that may be diagnostic of burning was severe damage to crystals from rapid dehydration …

Distribution And Occurrence Of Uranium In Coal And Its Migration Behavior During The Coal Utilization, Wang Wenfeng, Wang Wenlong, Liu Shuangshuang, Bai Hongyang, Wang Yulong, Duan Piaopiao, Qin Kemin, Chen Yilin

Coal Geology & Exploration

Coal and uranium resources are closely related in spatial disposition as well as mineralization, and the reasonable development, utilization and pollution control of them play an essential role in the sustainable development of our national economy and society. Based on a large number of literature research and the previous results of our research group, some conclusions were drawn with regard to the distribution and occurrence of uranium in coal `and its migration in the process of coal preparation, combustion and leaching:(1) The enrichment and mineralization of uranium in coal has reflected the evolution of coal-forming tectonics:The U-rich coal in Southwest …

The Future Environmental And Health Impacts Of Coal, Robert B. Finkelman, Amy L. Wolfe, Michael S. Hendryx

Faculty, Staff, and Affiliated Publications--KGS

In the United States, coal consumption in the last 12 years has declined from 1,045,140 million short tons in 2007 to 539,420 million short tons in 2019, a decrease of almost 50%. During that period the number of electric power coal generators has declined from 1,470 to 738 accounting for 21% of capacity. An even more dramatic decrease in coal use has occurred in Western Europe. This significant reduction in coal use and the concomitant closure of coal mines and coal-burning power plants will result in substantially cleaner air, reductions in respiratory problems such as asthma, less heart disease, fewer …

Nonwovens Of Ceramic Decorated Cellulose Based Fine Fibers For Leaded Water Purification, Alejandro J. Castillo

Theses and Dissertations

Fine fibers of cellulose acetate were Forcespun and used to make nonwoven mats of cellulose. Nonwovens were activated using a solution combustion synthesis which deposited iron nitride onto fibers. Cellulose and cellulose composite mats were tested as adsorbents for lead ion in water. Cellulose showed slightly higher adsorption capacities (mg/g) up to 1300 mg/g lead loading. Adsorption data were further analyzed using several isotherms, of which the Dubinin-Raduskevich gave the best fits.

Numerical Simulation About Fuel Injection Source Location Impacting On Turbulent Combustion Process, Sun Hui, Guangcheng Cai, Jiang Lin, Shibo Wang

Journal of System Simulation

Abstract: Fuel injection source location has very important influence on combustion process. It determines the location of the furnace flame. The three dimensional model of the furnace was established by the numerical simulation method. Under different conditions, the fuel injection source location on the temperature field within the furnace, the pollutant concentration field, and the flow field distribution inside the furnace combustion process were investigated. The results were compared and analyzed. After analysis, the results show that the fuel injection source location from 1.1 ~ 1.5 meter process of change, the average temperature within the furnace continue to rise, the …

Computational Analysis Of A New Planar Mixing Layer Flame Configuration To Study Soot Inception, Carmen Ciardiello

Honors Scholar Theses

The production of soot is omnipresent in society today. Soot is the product of many of the combustion processes that provide the bulk of the usable energy throughout the world. Furthermore, soot particulate poses a great danger to both the environment and all forms of life on Earth. It has proven to pollute ecosystems, foster health problems for human beings, and degrade air quality [1].

These dangers make studying and understanding soot particulate paramount for improving the quality of life. Thus, this study introduces a new flame configuration for studying soot inception. Presently, various common flame configurations have been found …

Experimental Demonstration Of Deterministic Chaos In A Waste Oil Biodiesel Semi-Industrial Furnace Combustion System, Shengyang Gao, Fashe Li, Qintai Xiao, Jianxin Xu, Huage Wang, Hua Wang

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

In this paper, the nonlinear dynamic characteristics of the oxygen-enriched combustion of waste oil biodiesel in semi-industrial furnaces were tested by the power spectrum, phase space reconstruction, the largest Lyapunov exponents, and the 0-1 test method. To express the influences of the system parameters, experiments were carried out under different oxygen content conditions (21%, 25%, 28%, 31%, and 33%). Higher oxygen enrichment degrees contribute to finer combustion sufficiency, which produces flames with high luminance. Flame luminance and temperature can be represented by different gray scale values of flame images. The chaotic characteristics of gray scale time series under different oxygen …

Bakken Flares And Satellite Images, University Of North Dakota. Energy And Environmental Research Center, Xiaodong Zhang

EERC Brochures and Fact Sheets

Fact sheet refuting a magazine article about Bakken gas flares and satellite images. Includes research into gas flares and satellite images by the University of North Dakota and the Energy & Environmental Research Center.

Pulse Power Effects On Transient Plasma Ignition For Combustion, David Wayne Alderman Ii

Electrical & Computer Engineering Theses & Dissertations

Transient plasma ignition (TPI) uses highly non-equilibrium plasmas, driven by less than 100 nanosecond, high-voltage pulses, to initiate combustion. The effects of pulse repetition frequency (PRF) and ultrashort nanosecond rise times on TPI are investigated in this work using lean, stoichiometric, and rich air-fuel mixtures at atmospheric pressure. Experimental data show the transient plasmas driven by ultrashort rise time, high voltage pulses at high PRF’s enhance the combustion of lean or stoichiometric air-methane mixtures in a static chamber. In particular, increasing PRF enhances the combustion performance by means of reduced delay times independent of the equivalence ratio of the air-fuel …

Examination Of Flow Dynamics And Passive Cooling In An Ultra Compact Combustor, Tylor C. Rathsack

Theses and Dissertations

The Ultra Compact Combustor (UCC) promises to greatly reduce the size of a gas turbine engine’s combustor by altering the manner in which fuel is burnt. Differing from the common axial flow combustor, the UCC utilizes a rotating flow, coaxial to the engine’s primary axis, in an outboard circumferential cavity as the primary combustion zone. The present study investigates two key UCC facets required to further this combustor design. The first area of investigation is cooling of the Hybrid Guide Vane (HGV). This UCC specific hardware acts as a combustor center body that alters the exit flow angle and acts …

Mineralogy And Geochemistry Of Feed Coals And Combustion Residues Of The Kangal Power Plant (Sivas, Turkey), Ali̇ İhsan Karayi̇ği̇t, Riza Görkem Oskay, Rod A. Gayer

Turkish Journal of Earth Sciences

This study focuses on mineralogical and geochemical compositions of feed coal (FC) and combustion residues, namely fly ash (FA) and bottom ash (BA) samples, obtained from the Kangal coal-fired power plant in central Turkey. The X-ray powder diffraction data indicate that carbonate and clay minerals are dominant phases in the FC samples. In the FA samples, quartz, hematite, anhydrite, lime, and feldspar are generally dominant and abundant phases, whereas calcite, ettringite, and portlandite are generally more abundant in the BA samples. The elements Mo, Cs, and U are significantly enriched in the studied FC, FA, and BA samples. The statistical …

Fuel Characteristics And Combustion Behavior Of Seaweed-Derived Hydrochars, İsmai̇l Cem Kantarli, Mehmet Pala, Yeli̇z Yildirim, Jale Yanik, Maria Helena Abreu

Turkish Journal of Chemistry

In this study, conversion of seaweeds into hydrochars was investigated with the aim of obtaining a renewable energy feedstock. The seaweeds Fucus serratus and Alaria esculenta, and a mixture of seaweeds, mainly consisting of Cystoseria sp$.$ and Laurencia sp$.$, were subjected to hydrothermal carbonization (HTC) in subcritical water at three different temperatures: 200, 225, and 250 $^{\circ}$C. Fuel characteristics and chemical properties of the derived hydrochars were determined using the standard fuel analysis and spectroscopic methods. The combustion behavior of seaweeds and hydrochars was examined via nonisothermal thermogravimetric analysis under air atmosphere. The seaweed-derived hydrochar yields were lower than those …

Characterization And Evaluation Of Cordless Nailer Performance For Liquid And Gaseous Fuels, Mark Carioscio

Master's Theses (2009 -)

The Paslode Cordless XP Framing Nailer is a combustion-powered nail gun that operates using a fuel blend of a propylene and 1-butene. This tool is designed to drive nails using a piston driven by a combustion reaction. The current fuel blend is able to fire approximately 1200 shots per fuel cartridge and match the energy output of pneumatic, corded nailers on the market. This thesis is written with the intent to gain a better understanding of the operation of the tool and how its performance varies when the fuel source is altered. A bizonal combustion model was created to simulate …

Reconstruction Of The 3d Temperature And Species Concentration Spatial Distribution Of A Jet Engine Exhaust Plume Using An Infrared Fourier Transform Spectrometer Hyperspectral Imager, Mason D. Paulec

Theses and Dissertations

The measurement of combustion byproducts is useful for determining pollution of any fuel burning application, efficiency of combustion, and determining detectability of aircraft exhausts. Both intrusive and non-intrusive techniques have been utilized to measure these quantities. For the majority of the non-intrusive techniques, the absorption and emission spectra of the gases are utilized for measurements. For this research, the use of the Telops Infrared Fourier Transform Spectrometer (IFTS) Hyperspectral Imager (HSI) was explored within the scope of combustion diagnostic methods, as an option for remote measurements of a jet turbine to determine concentration of species and temperature of the combustion …

Steric Effects Of Alkyl Ammonium Salts On The Combustion Of Exchanged Smectite Clays, Celeste A. Keith

Electronic Theses and Dissertations

Bomb calorimetry was explored as a new method for determining the cation exchange capacity (CEC) of clays. Smectite clays were modified with several alkyl ammonium salts varying in number of carbons and the spatial orientation of the carbons about the central nitrogen atom. The clays used, standards purchased from the Source Clay Repository, have CECs of 44, 80, 88, and 120 meq/100 g. Theoretically, the combustion energy of the organo-clays should be approximately the same for each salt. Any differences in energy would be due to the different structures of the salts and how they are oriented in the interlamellar …

Kinetic Study Of Free Radical-Radical Reactions Of Combustion Importance At Elevated Pressures, Chao Yan

Dissertations

Combustion mechanisms consist of hundreds elementary reactions of free radicals and stable molecules. Radical-radical elementary reactions play important roles due to the high concentration in which free radicals are accumulated in combustion systems. Radical-radical reactions are typically multi-channel. Some of the channels might be of chain propagation or even chain branching nature, while other channels might be of chain termination nature. The relative importance of different channels is pressure dependent. Compared to radical-molecule reactions, radical-radical reactions are much less studied. This is due to the difficulties of well characterized quantitative production of radical species as well as due to the …

Pyrolysis Of Jet Propellants And Oxidation Of Polycyclic Aromatic Radicals With Molecular Oxygen: Theoretical Study Of Potential Energy Surfaces, Mechanisms, And Kinetics, Daniel E. Belisario-Lara

FIU Electronic Theses and Dissertations

Two reaction classes have been studied computationally including the pyrolysis of various components of airplane fuels, such as decane, dodecane, butylbenzene isomers, and JP-10 (exo-tetrahydrodicyclopentadiene), and oxidation of a group of molecules belonging to the class of Polycyclic Aromatic Hydrocarbons (PAHs). Investigation of both reaction classes have been performed using ab initio quantum chemistry methods with the Gaussian 09 and MOLPRO programs at various levels of theory. Initially, Potential Energy Surfaces (PES) were generated at the G3(MP2,CC)/B3LYP/6-311G** level of theory for various radicals involved in the reactions as reactants, intermediates, transition states, and products. The next step was …

Alkyne Combustion: Experimental And Computational Studies Of Formyl Radical Production, Matthew Charles Drummer

Theses and Dissertations

The United States consumed a total of 97.4 trillion BTUs of energy in 2016 with over 80% of that energy consumption source being fossil fuel combustion. Before a combustion reactions reaches its end products, a number of intermediate products form and may react with other abundant atmospheric species to form aerosol particles and acid rain, both of which have potentially negative impacts on both human-made structures and the natural environment.

In an effort to counteract the consequences of fossil fuel combustion, scientists are interested in understanding the reaction mechanisms of hydrocarbon combustion reactions to understand which intermediate products form and …

Studies In Pressurized Oxy-Combustion: Process Development And Control Of Radiative Heat Transfer, Akshay Gopan

McKelvey School of Engineering Theses & Dissertations

Fossil fuels supply over 80% of the world’s primary energy and more than two-thirds of the world’s electricity. Of this, coal alone accounts for over 41% of the electricity supplied globally. Though coal is globally well-distributed and can provide stable and reliable energy on demand, it emits a large amount of carbon dioxide—a greenhouse gas responsible for global warming. Serious concerns over the implication of the increased global temperature have prompted the investigation into low carbon energy alternatives. The idea of capturing the carbon dioxide emitted from the combustion sources is considered as one of the viable alternatives. This would …

The Investigation And Characterization Of The Reaction Of 2-Methylfuran And 2-Methyl-3-Buten-2-Ol With O(3p) And The Photodissociation Of Xylyl Bromide Isomers, Yasmin Fathi

Master's Theses

This thesis has studied the oxidation behavior of different biofuels or additives, 2-methyl-3-buten-2-ol and 2-methylfuran, in combustion experiments at the Chemical Dynamics Beamline held at the Advanced Light Source of the Lawrence Berkley National Laboratory. The oxidation of these fuels were initiated through O(³P) and the combustion experiments were analyzed using a multiplexed chemical kinetics photoionization mass spectrometer with tunable synchrotron radiation. Products of the different reactions were identified using kinetic profiles and further characterized using the photoionization spectra. The amount of each species was calculated using branching fractions.

Additionally, the unimolecular dissociation of the xylyl bromide isomers …

Sub 2 Nm Particle Characterization In Systems With Aerosol Formation And Growth, Yang Wang

McKelvey School of Engineering Theses & Dissertations

Aerosol science and technology enable continual advances in material synthesis and atmospheric pollutant control. Among these advances, one important frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring nanoparticle properties requires a thorough understanding and precise control of the particle formation processes, which in turn requires characterizing nanoparticle formation from the initial stages. The knowledge on particle formation in early stages can also be applied …

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their …

Advancing Co2 Capture Technology, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about the Energy & Environmental Research Center’s (EERC’s) work with the U.S. Department of Energy (DOE), North Dakota Industrial Commission Lignite Research Council, and other partners to develop carbon capture technologies. Describes the EERC’s Partnership for CO₂ Capture (PCO₂C) Program, and outlines testing platforms and modeling capabilities.

Data Driven Low-Bandwidth Intelligent Control Of A Jet Engine Combustor, Nathan L. Toner

Open Access Dissertations

This thesis introduces a low-bandwidth control architecture for navigating the input space of an un-modeled combustor system between desired operating conditions while avoiding regions of instability and blow-out. An experimental procedure is discussed for identifying regions of instability and gathering sufficient data to build a data-driven model of the system's operating modes. Regions of instability and blow-out are identified experimentally and a data-driven operating point classifier is designed. This classifier acts as a map of the operating space of the combustor, indicating regions in which the flame is in a "good" or "bad" operating mode. A data-driven predictor is also …