Engineering Commons^™

Experimental Investigation Of Low Thermal Inertia Thermal Barrier Coatings For Spark Ignition Engines, John Gandolfo

All Theses

The application of thermal barrier coatings (TBCs) in spark ignition (SI) engines has historically been avoided due to the knock penalty associated with higher surface temperatures induced by the ceramic layer. However, advances in low thermal inertia coatings (i.e., temperature swing coatings) that combine low thermal conductivity with low volumetric heat capacity can prevent excessively high surface temperatures during the intake stroke and reduce or avoid knock while improving performance and efficiency. This thesis experimentally evaluates the effectiveness of these low thermal inertia coatings in a single-cylinder research engine representative of modern SI engines.

First, four pistons coated with a …

Enabling Premixed Hydrogen-Air Combustion For Aeroengines Via Laboratory Experiment Modeling, Christopher James Caulfield

Masters Theses

All combustion systems from large scale power plants to the engines of cars to gas turbines in aircraft are looking for new fuel sources. Recently, clean energy for aviation has come into the foreground as an important issue due to the environment impacts of current combustion methods and fuels used. The aircraft industry is looking towards hydrogen as a new, powerful, and clean fuel of the future. However there are several engineering and scientific challenges to overcome before hydrogen can be deployed into the industry. These issues
range from storing the hydrogen in a viable cryogenic form for an aircraft …

Multidimensional Transport-Coupled Numerical Investigation Of Non-Premixed Low-Temperature Flame In Atmospheric And High-Pressure Systems, Sudipta Saha

Theses and Dissertations

Gas-phase chemical reactions coupled with multidimensional fluid flow and heat and mass transport are found in various applications, i.e., from conventional engine applications to novel combustion techniques. With the goal of understanding such complex coupling in reacting flow systems, this dissertation work focuses on developing multi-physics simulation frameworks to investigate the effect of multidimensional transport on flame dynamics. This study primarily focuses on the modeling and simulation of low temperature flame formation in i) a canonical experimental setting with counterflow burners and ii) a supercritical water medium (i.e., hydrothermal flame).

In the first part of the dissertation, simulations of the …

Soot Formation And Ignition Characteristics Of Gasoline/Ethanol Fuel Blends Using A Rapid Compression Machine, Joseph Richard Keller Gross

Master's Theses (2009 -)

With the growing societal concern toward vehicle emissions, renewableforms of fuel are garnering increased interest in the fuel research world. While electrification is prevalent amongst the light duty sector, many challenges arise for such type of powerplant in heavy duty vehicles. Further, current heavy duty mixing-controlled combustion uses diesel fuel, which produces significant black carbon emissions in the exhaust. Alcohol fuels from biological sources serve as a promising source ofrenewable energy for heavy duty engines. The soot emissions and thermodynamic properties of ethanol/gasoline blended fuels must be understood and quantified in order to develop heavy duty combustion engine technology capable …

A Computational Fluid Dynamic Analysis Of Oxyacetylene Combustion Flow For Use In Material Response Boundary Conditions, Craig Meade

Theses and Dissertations--Mechanical Engineering

Oxyacetylene torches are used in the aerospace industry and research to test thermal protection system materials (TPS) due to their high flame temperatures and high heat flux capabilities. The purpose of this work is to determine a combustion model to accurately simulate the high temperature flow of an oxyacetylene torch. The flow conditions around a sample material can then be used as boundary conditions when modeling TPS material response. Two separate combustion models with equilibrium chemistry were investigated using ANSYS Fluent™; the Eddy-Dissipation Model, and the Partially Premixed model.The results of this study are compared to existing experiments for validation.

Computational Tools For Modeling And Simulation Of Sooting Turbulent Non-Premixed Flames, Victoria B. Stephens

Theses and Dissertations

Turbulent combustion systems are physically complex processes that involve many interdependent phenomena---including turbulent fluid dynamics, multi-component mass transfer, convective and radiative heat transfer, and multiphase flow---that occur over a wide range of length and time scales. Modeling and simulation studies complement experimental work by implementing and validating models and providing predictive capabilities, but current software tools are often limited by a lack of standardization and best practices, non-robust implementation, or over-specialization. Some topics in combustion CFD research, notably radiative heat transfer and soot modeling, are critically underrepresented in simulation studies as a result of software limitations. This project establishes and …

A Comparative Evaluation Of Oxidation And Combustion Phenomena In Ti-6al-4v Exposed To Earth Re-Entry And Arc-Jet Test Environments, Arlene Smith

Open Access Theses & Dissertations

The Ti-6Al-4V alloy is widely used in aerospace applications for its beneficial combination of properties. However, this alloy has high solubility for oxygen and thus a high reactivity. Recovered data contained within the Columbia artifacts suggests that this alloy underwent an accelerated degradation and combustion reaction when exposed to the high enthalpy, low-pressure surroundings experienced during reentry into Earth's atmosphere. Arc-jet testing has provided a simulated aerothermodynamic heating environment to mimic what the spacecraft endured. When the effect of thermal alteration on this alpha-beta phase alloy was investigated during previous studies, optical metallography and microhardness tests revealed inconsistencies between samples …

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 …

Direct Numerical Simulation Of Supercritical Co2 Mixing And Combustion, Syed Mohammad Ovais

All Dissertations

The supercritical CO₂ power cycle (sCO₂ ) is a relatively new technology, which promises to reduce CO₂ emissions with potentially higher efficiencies. However due to challenging conditions posed by supercritical pressures, the mixing and ignition phenomena in sCO₂ combustion is relatively less understood and studied. The primary objective of the current study is to investigate these fundamental processes using homogeneous ignition calculations (HMI) and direct numerical simulations (DNS). Broadly, the study is divided into two major parts. In the first part supercritical mixing in sCO₂ relevant conditions is investigated. To achieve this, DNS of temporally …

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. …

Effect Of Process Control Agents Used In Mechanochemical Synthesis On Properties Of The Prepared Composite Reactive Materials, Mehnaz Mursalat

Dissertations

The study explores synthesis and reactivity of new reactive materials prepared by ball milling. High-energy ball milling became a ubiquitous mechano-chemical tool to manufacture diverse powders, from pharmaceuticals or foods to alloys to new solid rocket propellants. It enabled a dramatic expansion of the range of chemical compositions obtainable; however, it did not so far, allowed one to fine-tune morphology or interfaces in the generated powders. It is shown in this work how different process control agents (PCAs) can serve to tune the powder morphology and reactivity. Commonly used as lubricants and cooling agents during milling, liquid PCAs can be …

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 …

Self-Sustaining Smouldering Combustion Of Granular Activated Carbon Contaminated With Per- And Polyfluoroalkyl Substances – Fluorine Mass Balance And Enhanced Methods Of Mineralization, Brian Gerald Harrison

Electronic Thesis and Dissertation Repository

Per- and polyfluoroalkyl substances (PFAS) are a large group of anthropogenic compounds. Long-term use has led to widespread environmental contamination, and PFAS source zones will require cleanup.

Self-sustaining Treatment for Active Remediation (STAR) is a thermal treatment technology that employs smouldering combustion as a method of soil treatment. Smouldering can be self-sustaining and is thus more energy-efficient. Previous research applying STAR to PFAS-contaminated soil and granular activated carbon (GAC) showed promise, as PFAS were removed from soil.

This study clarified the potential of STAR as a treatment option for PFAS. This study is unique in how thoroughly it characterized the …

An Experimental Study Of Fuel Selection For A Gasoline Multi-Mode, Spark Ignited – Compression Ignition Engine, Zachary J. Stanchina

Dissertations, Master's Theses and Master's Reports

In this study of fuels of different reactivities and their performance in a low-temperature combustion (LTC) engine. The engine was a 2.2L CRDI engine code D4HB provided by industry partner Hyundai America Technical Center inc. (HATCI). The engine was instrumented with in-cylinder pressure sensors allowing for monitoring of the combustion process.

First, the engine was operated with standard US pump grade gasoline, Research Octane number (RON) 91 E10, to find initial operation conditions as well as control points of stable operation for daily checks on system conditions.

Tested were 8 different fuel blends, the four base blends were provided by …

Cfd And Heat Transfer Analysis Of Rocket Cooling Techniques On An Aerospike Nozzle, Geoffrey Sullivan

Electronic Theses and Dissertations

In recent years the development of rocket engines has been mainly focused on improving the engine cycle and creating new fuels. Rocket nozzle design has not been changed since the late 1960s. Recent needs for reliable and reusable rockets, as well as advancements in additive manufacturing, have brought new interest into the aerospike nozzle concept. This nozzle is a type of altitude adjusting nozzle that is up to 90% more efficient than bell nozzles at low altitudes and spends up to 30% less fuel. Since the nozzle body is submerged in the hot exhaust gasses it is difficult to keep …

Investigations Of The Low Temperature Combustion Regions And Emissions Characteristics Of Aerospace F24 In A Constant Volume Combustion Chamber And A Common Rail Direct Injection Ci Engine, Richard C. Smith Iii

Electronic Theses and Dissertations

A study was conducted to investigate the low temperature combustion (LTC) regions of aerospace F24 and ULSD in the static setting of a CVCC and the dynamic setting of a CRDI research engine. This research is conducted to reduce in-cylinder emissions by understanding and implementing a technique to achieve an extended LTC. Emissions data for this study were collected during the operation of the CRDI research engine with a MKS 2030 FTIR and an AVL Microsoot 483. The parameters researched within the static setting of the CVCC included the determinations of the cool flames and NTC regions within the LTHR …

A Study Of Greenhouse Gas Emissions And Performance Of An Internal Combustion Engine Operating On Landfill Gas Blends As Fuel, Lauren T. Creadore

Dissertations and Theses

Landfill gas (LFG) is an abundant resource naturally occurring from the decomposition of municipal solid waste. It can be generated in U.S. landfills at a rate of 24.2 to 59.1 GNm³ per year.¹ LFG presents both a problem and solution with respect to global warming. Composed of carbon dioxide (CO₂, 30-40%) and methane (CH₄, 45-55%), as well as nitrogen (N₂, 10-15%), oxygen (O₂, 0-5%), and other trace gasses¹, LFG that is permitted release into the atmosphere will contribute to the greenhouse gas effect due to the presence of …

Experimental Setup Of A Rapid Compression Machine For Spark Ignition Studies, Daniel Llaguno

Electronic Theses and Dissertations

The main objective of this thesis is to document the design and development of a rapid compression machine (RCM). A series of tests were performed to verify the operation of the system using the compression of air. Finally, an experiment was conducted to validate the auto-ignition temperature of DME under HCCI mode. Based on the first version of the RCM, improvements were made to speed up the compression process, and to create the conditions required for the auto-ignition of a DME-air mixture. The inlet diameter of the pneumatic actuation cylinder was increased to reduce the choking effect of the air …

Analysis Of Combustion In Plasma Electrolytic Oxidation (Peo) Coatings Of The Piston Surface In Spark Ignition Engines, Brendon Bain

Electronic Theses and Dissertations

With the global effort to “green” the transportation industry, the internal combustion engine (ICE) is required to reduce its carbon footprint and can do so by increasing efficiency. Plasma Electrolytic Oxidation (PEO) coatings confer properties of high wear and corrosion resistance, high hardness, excellent adhesion and a superior thermal barrier to their substrate, suggesting that coating of ICE components has the potential to greatly improve the combustion efficiency. The primary objective of this thesis is to analyze the effects of PEO coating on the surface of pistons in a spark ignition ICE, with the goal of increasing efficiency, to address …

Influences Of The Internal Residual On Combustion Instabilities In The Misfire And Partial Burn Regimes Of A Dilute Spark-Ignition Engine, Rachel Inez Stiffler

Doctoral Dissertations

"Dilution in spark-ignition (SI) engines can improve fuel consumption and reduce emissions; however, increased levels of dilution either from excess oxidizer or exhaust gas recirculation (EGR) causes combustion to become more strained and cycle-to-cycle variations increase. At high levels of dilution incomplete combustion events (i.e. misfires and partial burns) start to occur, which cause combustion instabilities and eventually a dilute limit is reached. It is known the combustion instabilities seen are primarily due to the feed-forward mechanism present in the residual gases, but it is still unknown what about the residual is influencing the dynamics under high levels of dilution …

Mean Pressure Gradient Effects On Flame-Flow Dynamics In A Cavity Combustor, David M. Smerina

Honors Undergraduate Theses

Pressure gradient confinement effects are experimentally investigated within a cavity combustor to analyze the flame interactions of premixed, cavity stabilized, flames in a high-speed combustor. Pressure gradient confinement effects are generated in a dual mode ramjet-scramjet (DMSR) by varying the wall geometry to form converging, diverging, and nominal configurations. The velocity field and flame position are captured temporally using simultaneous high-speed particle image velocimetry (PIV) and CH chemiluminescence. The evolution of the flow field and flame structure are analyzed, and the high temporal resolution of these measurements allows for the characterization of turbulence-flame interactions. Consideration of the combustion mode and …

Completion And Initial Testing Of A Pressurized Oxy-Coal Reactor, Scott Hunsaker Gardner

Theses and Dissertations

Oxy-combustion is a process which removes nitrogen from air prior to combustion in order to produce a high concentration of CO2 in the exhaust. This enables CO2 liquefaction, transport, and storage to greatly reduce CO2 emissions to the atmosphere. Atmospheric oxy-coal combustion has been successfully demonstrated at industrial scales and could be retrofit in existing coal boilers, but thermodynamic efficiencies are low and therefore uneconomical. Pressurized oxy-coal combustion has the potential for higher efficiency and lower cost but requires new technologies related to the coal feed system, the burner, and ash management. This project describes work needed to complete the …

Development Of A Converging-Channel Drop Tower For Sphere Symmetric Isolated Single Droplet Combustion, Nicholas Alexander Demaio

Theses and Dissertations

The dawn of a new Space Age is upon us; Microgravity combustion of hydrocarbon fuels is a popular method of research and characterization. This allows for a one-dimensional analysis by suppressing the buoyancy forces produced by gravity and the large temperature differential between the flame boundary and the surrounding air. The current testing methods are expensive and require extensive preparation on the researchers behalf. There is a need to investigate an alternative method that is inexpensive, repeatable, and comparable to the other approaches that coincides with the literature.

A low-cost converging-channel drop tower was designed and fabricated for sphero-symmetric single …

Development Of Experimental And Numerical Methods For Investigations Of High-Octane Fuels In Heavy-Duty Applications, Jared James Zeman

Master's Theses (2009 -)

Increasingly stringent emissions regulations has threatened the existence of the internal combustion (IC) engine. In some transportation sectors, non-IC engine powertrains have the potential to be a logical solution. However, in the heavy-duty sector, the IC engine is predicted to remain the dominant propulsion method for the foreseeable future. With ever-increasing demand for heavy-duty power generation platforms, the primary focus for the development of the future heavy-duty IC engine needs to be on increasing engine efficiency and the adoption of lowlife-cycle carbon, clean burning fuels, e.g. methanol. The fuel ignition properties of these fuels, e.g. high octane, cause difficulties when …

Fluorine-Based Inorganic Oxidizers For Use In Metal-Based Reactive Materials, Siva Kumar Valluri

Dissertations

This work explores inorganic fluorides as oxidizers for fuel-rich reactive materials. A preliminary assessment of metal fluorides accounting for their enthalpy of formation points to bismuth (III) fluoride, BiF3 and cobalt (II) fluoride, CoF2 as oxidizers of interest. Initially, composite powders of aluminum with chosen fluorides at 50-50 wt. % are prepared by arrested reactive milling. Despite an increase in reactivity and lowtemperature ignition, the prepared composite powders are insensitive to initiation by electro-static discharge (ESD), making them attractive alternative to analogous thermites having very high ESD sensitivity. In air, the composite powder particles burn faster than reference aluminum particles …

Investigation Of Various Jet Configurations On Jet-In Crossflow Flame Characteristics At Elevated Pressures, Max K. Fortin

Honors Undergraduate Theses

The goal of this study is to investigate how varying the configuration of an axially staged combustion test facility affects the resultant flame and its relevant characteristics. Such relevant characteristics are the jet liftoff and the centerline jet trajectory. The configurations that are primarily being investigated are varied jet configuration diameters, 4mm and 12.7mm, preheated and non-preheated fuel, and different fuels. The testing facility is located at the University of Central Florida in the PERL (Propulsion and Energy Research Lab) facility. The facility allows for modeling an industrial turbine combustor, specifically an axial staged combustor with a Jet-In-Crossflow …

Experimental Study Of A Liquid Fuel Bluff Body Flame At Elevated Pressures, Karam Paul

Honors Undergraduate Theses

The purpose of this research was to operate a bluff body flame holder with the objective of stabilizing a flame at elevated pressures over a range of equivalence ratios. The ability to have a ground-based test rig capable of maintaining stable flames at high pressures and temperatures is critical in understanding flames present in modern jet engines and gas turbine technologies. The facility was reconfigured multiple times and the resultant flame was imaged within the optical test section. A converging nozzle was utilized to choke the flow and vary the operating pressures up to 5 atm. By regulating mass flow …

An Investigative Study Of Combustion And Emissions With Noise And Vibrations Of Synthetic Fuels Within An Aero-Gas Turbine, Camille J. Phillips

Honors College Theses

The pollution from the aerospace transportation is rapidly becoming the largest source of greenhouse gas (GHG) emissions. The FAA expects aviation emissions to almost triple by 2050, making the aerospace industry responsible for the release of approximately 25% of the global carbon dioxide budget. These aviation emissions, including CO2 and NOx, as well as other GHGs, contribute to the destruction of ozone layer. Carbon dioxide emissions have a particularly negative effect on humans, leading to airway diseases especially in children and elderly. To combat the addition of further GHG emissions into the atmosphere, it is necessary to minimize the usage …

Portable Calorimeter For Fire Experiments, Kayla Collins, Kara Hewson, Christopher Chen, Joel Keddie

Mechanical Engineering

Executive Summary

An oxygen consumption calorimeter works by measuring the heat release rate of a burning substance. This value is calculated by measuring the oxygen and byproducts in smoke from afire.In order to get these values two types of sensors were used. A non-dispersive infrared sensor (NDIR) that measured CO and CO2 and a zirconium O2 sensor were used to find their respective gas concentrations.The design to calculate the heat release rate is focused on maximizing sensor accuracy and portability while simplifying the manufacturing by using off-the-shelf components. The goal included making the system simple to recreate and package in …

Design And Analysis Of A Compact Combustor For Integration With A Jetcat P90 Rxi, Daniel Holobeny

Theses and Dissertations

Ultra Compact Combustors are a novel approach to modern gas turbine combustor designs that look to reduce the overall combustor length and weight. A previous study integrated an Ultra Compact Combustor into a JetCat P90 RXi turbine engine and achieved self-sustained operation with a length savings of 33% relative to the stock combustor. However, that combustor could not operate across the full stock engine performance range due to flameout at increased mass ow rates as reactions were pushed out of the primary zone. To ensure reactions stayed in the primary zone, a new design with a larger combustor volume was …