Browsing by Author "Marchese, Anthony J., committee member"

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Open Access
Applications of field programmable gate arrays for engine control
(Colorado State University. Libraries, 2012) Viele, Matthew, author; Willson, Bryan D., advisor; Marchese, Anthony J., committee member; Meroney, Robert N., committee member; Troxell, Wade O., committee member
Automotive engine control is becoming increasingly complex due to the drivers of emissions, fuel economy, and fault detection. Research in to new engine concepts is often limited by the ability to control combustion. Traditional engine-targeted micro controllers have proven difficult for the typical engine researchers to use and inflexible for advanced concept engines. With the advent of Field Programmable Gate Array (FPGA) based engine control system, many of these impediments to research have been lowered. This dissertation will talk about three stages of FPGA engine controller application. The most basic and widely distributed is the FPGA as an I/O coprocessor, tracking engine position and performing other timing critical low-level tasks. A later application of FPGAs is the use of microsecond loop rates to introduce feedback control on the crank angle degree level. Lastly, the development of custom real-time computing machines to tackle complex engine control problems is presented. This document is a collection of papers and patents that pertain to the use of FPGAs for the above tasks. Each task is prefixed with a prologue section to give the history of the topic and context of the paper in the larger scope of FPGA based engine control. The author of this study founded, built up, and eventually sold Drivven Inc., a company dedicated to the implementation of FPGAs in engine control. As a result, this study spans a decade of time where we see the first few papers related to FPGA based engine control, and concludes with FPGA based engine controllers being the de facto standard for advanced combustion research.
Open Access
Battery end-of-life considerations for plug-in hybrid electric vehicles
(Colorado State University. Libraries, 2011) Wood, Eric, author; Bradley, Thomas H., advisor; Marchese, Anthony J., committee member; Young, Peter M., committee member
Plug-in hybrid electric vehicles (PHEVs) represent an advanced vehicle technology with the potential to displace petroleum consumption with energy generated on the US electric grid. While many benefits have been associated with the increased electrification of the US vehicle fleet, concerns over battery lifetime and replacement costs remain an obstacle to widespread PHEV adoption. In order to accurately determine the lifecycle cost of PHEVs, assessment studies must make use of informed assumptions regarding battery degradation and replacement. These assumptions should approach end-of-life (EOL) metrics not only in terms of pack level degradation but also loss of vehicle efficiency and performance in order to accurately represent consumer incentive for battery replacement. Battery degradation calculations should also remain sensitive to the range of ambient conditions and usage scenarios likely to be encountered in the US market. Degradation resulting from a single duty cycle has the potential to misrepresent battery life distributions for the US fleet. In this study, the sensitivity of PHEV lifecycle cost to the battery replacement assumption is explored to underscore the need for an improved understanding of PHEV battery EOL conditions. PHEV specific battery test results are presented to evaluate the ability of industry standard life test procedures to predict battery degradation in PHEVs. These test results are used as inputs to a vehicle simulation program to understand changes in efficiency and performance with respect to battery degradation using a light commercial vehicle simulated as a blended-mode capable, parallel PHEV20. A predictive battery degradation model based on empirical data is used to explore sensitivity of battery wear to various parameters including design variables, ambient conditions, and usage scenarios. A distribution of expected wear rates for a light-duty, midsize passenger vehicle modeled as a series PHEV35 is presented to highlight the uncertainty associated with battery life subject to US ambient conditions and driving distributions. The results of this study show that active management of PHEV battery degradation by the vehicle control system can improve PHEV performance and fuel consumption relative to a more passive baseline. Simulation of the PHEV20 throughout its battery lifetime shows that battery replacement will be neither economically incentivized nor necessary to maintain performance. The spectrum of climate and usage conditions PHEVs are expected to face in the US market suggest that the assumption of a single average ambient condition for battery wear calculations may not be representative of observed behavior in the fleet. These results have important implications for techno-economic evaluations of PHEVs which have treated battery replacement and its costs with inconsistency.
Open Access
Cavity enhanced instruments for detection of hydrogen chloride and aerosol optical extinction
(Colorado State University. Libraries, 2013) Franka, Isaiah S., author; Yalin, Azer P., advisor; Kreidenweis, Sonia M., committee member; Marchese, Anthony J., committee member
This thesis concerns the development of cavity enhanced instruments for atmospheric science studies. Hydrochloric acid (HCl) is an important reservoir species for active halogens which are thought to participate in cycles that deplete ozone. In order to understand these halogens and their effect on ozone depletion, a cavity ring-down spectroscopy (CRDS) based instrument was developed for ultra-sensitive HCl concentration measurements. The instrument has a (1σ) limit of detection of 10 pptv in 5 min and has high specificity to HCl. Aerosols are a fundamental contribution to Earth's radiation budget and represent one of the largest unconstrained unknowns in estimating climate change. The effect of aerosols on climate and air quality is closely tied to their spectral properties as well as particle chemical composition, size, and shape. Aerosol extinction coefficient (sum of light attenuation by scattering and absorption coefficients) is an important optical property for determining aerosol radiative forcing. A broadband cavity enhanced absorption spectroscopy (CEAS) laser-based instrument for measurement of aerosol extinction has been created with a minimum detectable extinction coefficient of 8x10-8 cm-1 for 10-ms collection time. This thesis details the development and validation of these cavity enhanced spectroscopy based instruments.
Open Access
Cavity enhanced Thomson scattering for plasma diagnostics
(Colorado State University. Libraries, 2019) Friss, Adam J., author; Yalin, Azer P., advisor; Marchese, Anthony J., committee member; Polk, James E., committee member; Williams, John D., committee member; Yost, Dylan C., committee member
Measurements of electron number density (nₑ) and electron energy distribution function (EEDF) are of great importance to the study of weakly ionized plasmas, such as those used in laser preionization, semiconductor processing and fabrication, electric propulsion devices, and atmospheric pressure plasmas. Currently, these parameters can be measured by physical probes, e.g. Langmuir probes, or with the use of non-intrusive Laser Thomson Scattering (LTS). While physical probe measurements have been an indispensable tool of the plasma physics community, they affect plasma source operation and result in unwanted plasma perturbation. LTS measurements are appealing due to the non-perturbing nature of the technique, but suffer from low signal levels and optical interference, making application to low-density plasma systems very challenging. This dissertation describes the development of a novel cavity enhanced Thomson scattering (CETS) diagnostic that enables sensitive, non-perturbing measurements of plasma properties. The technique is based upon frequency locking a high-power, narrow-linewidth continuous wave (CW) laser source to a high-finesse optical cavity to build-up intra-cavity power to a level where it can serve as an interrogation laser source. In this way, intra-cavity powers as high as ~12 kW have been generated from a ~5 W laser source and sensitive measurements on a plasma source and gas samples placed within the optical cavity were performed. Despite the CETS technique being widely applicable to a variety of plasma sources, this work focused on the measurement of electric propulsion devices, such as hollow cathodes and Hall effect thrusters. These devices are used as in-space propulsion systems on satellites and scientific probes and may be used as the primary in-space propulsion systems for exploration of the Moon, Mars, and beyond. This work describes the development of the CETS diagnostic including the cavity locking approach, creation of a gas and plasma scattering model, and the development of both a low- and high-power experimental instrument. CETS is demonstrated by performing rotational Raman and Rayleigh scattering measurements on a variety of gases and by performing Thomson scattering measurements in the plume of a hollow cathode. The cathode measurement campaign was conducted over a range of operating conditions, and electron densities and temperatures in the range of ~10¹² cm⁻³ and ~3 eV were measured. Finally, a mobile fiber coupled version of the CETS setup designed for use in large vacuum facilities is presented, and Thomson scattering measurements made with the mobile instrument in the plume of a hollow cathode are discussed.
Open Access
Computer aided engineering of an automobile gasoline refueling system
(Colorado State University. Libraries, 2018) Dake, Mangesh, author; Windom, Bret C., advisor; Marchese, Anthony J., committee member; Venayagamoorthy, Karan S., committee member
A vehicle's refueling system, including components which make up the Onboard Refueling Vapor Recovery (ORVR) system, must be designed to meet federally set evaporative hydrocarbon emission regulations and other performance issues inherent to the refueling process, such as premature click-off of the refueling nozzle and spit-back. A Computational Fluid Dynamics (CFD) model able to predict the performance of a vehicle's refueling system could be a valuable tool towards the development of future gasoline refueling system designs, saving the Original Equipment Manufacturer's time and money currently invested in the research and development of these systems. To create an adequate model required for Computer Aided Engineering (CAE) of a modern refueling system, it is paramount to accurately predict the fluid dynamics through and out of a gasoline refueling nozzle, within the different components inside the refueling system, and the outlets of the fuel tank. Using CFD, this study aims to predict the performance of a refueling system. The commercial CFD software, Star-CCM+, was used to model fuel flow through a currently in production refueling system geometry. Experiments were conducted using a test setup to mimic the simulated refueling system to carefully describe the system's boundary and initial conditions and to evaluate the CFD results. It was found that modeling of the fluid dynamics through the air entrainment and pressure port geometries within the refueling nozzle were needed to accurately capture fuel spray behavior as demonstrated by experiments. By monitoring the amount of liquid fuel contacting the pressure port on the refueling nozzle, the simulations are able to identify fillerpipe designs that fail as a result of early click-off. Simulations of the complete refueling system, while neglecting phase change of the fuel, were able to predict the trends and dynamics of the tank pressure experienced by the experiments for varying fuel pump flow rates. The study acts as a guide for future refueling simulations involving fuel evaporation, for which initial results are presented.
Open Access
Computer-aided engineering and design of internal combustion engines to support operation on non-traditional fuels
(Colorado State University. Libraries, 2020) Valles Castro, Miguel, author; Windom, Bret C., advisor; Marchese, Anthony J., committee member; Daily, Jeremy, committee member
Traditional fuels like gasoline and diesel make up ~37 % of the US energy production; because of that, they are rapidly depleting their finite resources. These traditional fuels are also primary contributors to greenhouse gases, global warming, and particulate matter, which are bad for the environment and human beings. For that reason, research in non-traditional fuels (e.g., Carbon neutral biofuels, low GHG emitting gaseous fuels including NG and hydrogen) that achieve greater if not similar efficiencies compared to traditional fuels is gaining traction. On top of that, emission requirements are becoming even more strenuous. Engineers must find new ways to investigate non-traditional fuels and their performance in internal combustion engines while permitting the engine-fuel system's low-cost design. This being the case, Computer-Aided Engineering (CAE) tools like Computational Fluid Dynamics (CFD) and chemical kinetics solvers are being taken advantage of to assist in the research of these non-traditional fuel applications. This thesis describes the use of CONVERGE CFD to investigate two different non-traditional fuel applications, namely, the retrofitting of a premixed gasoline two-stroke spark-ignited (SI) engine to function with multiple injections of JP-8 fuel and to retrofit a diesel compression-ignited engine into a premixed anode tail-gas SI engine. The first application described herein uses a solid oxide fuel cell "Anode Tail-gas," which has similar syngas characteristics in a spark-ignited engine. Anode Tail-gas is a byproduct from an underutilized Metal Supported Solid Oxide Fuel Cell (MS-SOFC) used in a high efficiency distributed power (~100 kWe) system. Gas turbines or reciprocating ICEs typically drive distributed power systems of this capacity because they can quickly react to change in demand but traditionally have lower thermal efficiencies than a large-scale Rankine cycle plant. However, with the MS-SOFC, it may be possible to design a 125 kWe system with 70 % efficiency while keeping the system cost-competitive (below $1000/kW). The system requires a ~14 kW engine that can operate at 35 % efficiency with the highly dilute (17.7% H2, 4.90 % CO, 0.40% CH4, 28.3 % CO2, 48.7 % H2O) Anode Tail-gas to meet these lofty targets. CAE approaches were developed and used to identify high-efficiency operation pathways with the highly diluted anode tail-gas fuel. The fuel was first tested and modeled in a Cooperative Fuel Research (CFR) engine to investigate the anode tail gas's combustibility within an IC engine and to provide validation data with highly specified boundary conditions (Compression Ratio (CR), fuel compositions, intake temperature/pressure, and spark timing). A chemical mechanism was selected through CAE tools to represent the highly diluted fuel combustion best based on the CFR data. Five experimental test points were used to validate the CFD model, which all were within a maximum relative error of less than 8 % for IMEP and less than 4 crank angle degrees for CA10 and CA50. The knowledge gained from the CFR engine experiments and associated model validation helped direct the design of a retrofitted Kohler diesel engine to operate as a spark-ignited engine on the anode tail gas fuel. CFD Investigations into spark plug and piston bowl designs were performed to identify combustion chamber design improvements to boost the Kohler engine's efficiency. Studies revealed that piston designs incorporating small clearance heights, large squish areas, and deep bowl depths could enhance efficiency by 5.41 pts with additional efficiency gain possible through piston rotation. The second fuel investigation was a jet propellant fuel called "JP-8," which was deemed non-tradition when used in a two-stroke UAV engine to satisfy the military's single fuel policy requirements. The JP-8 fuel proved challenging in this application due to its significantly lower octane number and volatility than gasoline and experienced knock when used as a homogeneous premixed mixture within the simulated UAV platform. Although with CFD modeling, it was possible to reduce the severity of knock by using eight rapid direct injections of JP-8 at 20 µm diameter droplets. With further investigation, it might be possible to reduce further the severity of knock using CFD through more advanced injection strategies.
Open Access
Continuous-wave cavity ring down spectroscopy sensor for Hall thruster erosion measurement
(Colorado State University. Libraries, 2011) Tao, Lei, author; Yalin, Azer P., advisor; Marchese, Anthony J., committee member; Menoni, Carmen S., committee member; Williams, John D., committee member
Hall thruster and other Electric propulsion (EP) devices have become appealing alternatives to traditional chemical propulsion thrusters for space applications due to this high specific impulse (Isp), which allows high fuel efficiency. However, the uncertainty of the lifetime for Hall thruster hinders its development in future applications requiring a long operational time (several thousands of hours). Sputter erosion of boron nitride (BN) acceleration channel wall is principal lifetime limitation for Hall thrusters. The sputtered particles can redeposit causing a critical contamination effect. There is an urgent need for improved experimental tools to understand the BN sputter erosion process and lifetime assessment for Hall thrusters. The present research applies continuous wave cavity ring down Spectroscopy (CW-CRDS) as a diagnostic tools to study the sputter erosion process for Hall thrusters. Two CW-CRDS erosion sensors have been developed for in situ monitoring of sputtered manganese (Mn) and BN. As a stepping stone towards BN detection, a Mn erosion sensor was first developed. This sensor is based upon detection of Mn atoms via an absorption line from ground state at a wavelength of 403.076 nm. Measurements of sputtered Mn atom number density and its hyperfine structure are presented. Additionally, end-point detection has been done for a multilayer target, which can be potentially applied to the industrial sputtering systems. The same system has also been applied for detecting eroded atoms from the acceleration channel wall in an anode layer type Hall thruster. The results show the validity of the CW-CRDS erosion sensor for Hall thruster lifetime estimation. A BN erosion sensor has also been developed for the detection of sputtered boron atoms from Hall thrusters by probing atomic absorption lines of boron (250 nm) with CW-CRDS. A photonic crystal fiber was used to couple the ultraviolet laser light to the cavity within the vacuum chamber. The experimental detection limits and signal-to-noise values show potential for Hall thruster BN erosion studies. Finally, the velocity distributions of sputtered boron atoms at different ion energies were measured with laser induced fluorescence (LIF). These velocity distribution are necessary for interpretation of signals from the BN erosion sensor.
Open Access
Developing high-performance microfluidic paper-based analytical devices
(Colorado State University. Libraries, 2018) Nguyen, Michael Paul, author; Henry, Charles S., advisor; Van Orden, Alan, committee member; Strauss, Steven H., committee member; Marchese, Anthony J., committee member
Small-scale systems to manipulate fluids, also referred to as microfluidics, have proven effective at reducing analytical costs by increasing the portability of diagnostic devices. Microfluidic paper-based analytical devices (μPADs) have also proven to be cost-effective while remaining disposable, possessing the capacity to store reagents, and producing quantitative diagnostic results. These benefits have lead the field to increase exponentially since the seminal publication, with 63 review articles currently published on the subject. Most articles in the field focus on three topics: 1) new applications, 2) new methods of analysis with broad applicability, and 3) new ways to manipulate fluids in devices. A host of new analytes and clever architectures are being developed for a variety of applications, including environmental analysis and diagnostics. However, several critical obstacles remain for μPADs including improving detection limits, reducing analysis time, increasing selectivity, and increasing the range of measurable analytes. The work described in this dissertation presents three studies that address these issues. The first study examines simple factors to improve sample delivery through a cellulose channel that directly and significantly impact detection limits. Here I show how common μPAD designs lose roughly 50% of sample prior to quantification. This major challenge has been solved through geometry changes that led to a 94% increase in signal when compared to standard designs. While Ni(II) detection was used to study the system, the methods are translated to Mn(II) detection, antibiotic purity tests and determination of nitrite in saliva suggesting the broad applicability of the methods. The second study aimed at decreasing analysis time by utilizing multiple layers of paper in μPADs. I present the ability to tune speed, distance, and time at which the fluid travels with the formation of a microchannel between the layers. By increasing both the number of paper layers and the distance between them, the solution flux is dramatically increased in agreement with theoretical predictions. However, experimental flow rates deviate from predictions at large spacings. The detailed characterization and current understanding of the fast flow properties allow us to design assays that take seconds to complete instead of minutes along with improved analytical performance.Developing a selective test for Al(III) in food, mining and water samples is the goal of the last study. To address this need, a fluorescent ligand selective for Al(III) was synthesized and characterized on a μPAD for the first time. A distance-based μPAD for Al(III) exhibited a linear response from 2–55 ppm and a limit of detection of 2 ppm. This chemistry was also further developed with a radial uPAD that measures diameter of a color response as opposed to distance. Despite a smaller linear range with this radial device, the limit of detection is 0.9 ppm, which is below the concentration relevant to plant health. All three of these studies highlight improving the analytical performance of μPADs with carefully selected assays and deliberate device design.
Open Access
Development of microsystems for point-of-use microorganism detection
(Colorado State University. Libraries, 2018) Wang, Lei, author; Dandy, David S., advisor; Tobet, Stuart A., committee member; Henry, Chuck S., committee member; Geiss, Brian J., committee member; Bailey, Travis S., committee member; Marchese, Anthony J., committee member
To view the abstract, please see the full text of the document.
Open Access
Dual fuel engine combustion and emissions - an experimental investigation coupled with computer simulation
(Colorado State University. Libraries, 2014) Wan Mansor, Wan Nurdiyana, author; Olsen, Daniel B., advisor; Marchese, Anthony J., committee member; Xinfeng, Gao, committee member; Sharvelle, Sybil, committee member
Alternative fuels have been getting more attention as concerns escalate over exhaust pollutant emissions produced by internal combustion engines, higher fuel costs, and the depletion of crude oil. Various solutions have been proposed, including utilizing alternative fuels as a dedicated fuel in spark ignited engines, diesel pilot ignition engines, gas turbines, and dual fuel and bi-fuel engines. Among these applications, one of the most promising options is the diesel derivative dual fuel engine with natural gas as the supplement fuel. This study aims to evaluate diesel and dual fuel combustion in a natural gas-diesel dual fuel engine. More dual fuel engines are being utilized due to stricter emission standards, increasing costs of diesel fuel and decreasing costs of natural gas. Originally sold as diesel engines, these units are converted to natural gas-diesel fuel engines using an aftermarket dual fuel kit. As natural gas is mixed with air intake, the amount of diesel used is reduced. The maximum natural gas substitution is limited by knock or emissions of carbon monoxide and total hydrocarbons. In this research a John Deere 6068H diesel engine is converted to dual fuel operation. The engine is a Tier II, 6 cylinder, 6.8 liter, 4-stroke compression ignition engine with a compression ratio of 17:1 and a power rating of 168 kW at 2200 rpm. A natural gas fuel system is installed to deliver fuel upstream of the turbocharger compressor. The engine operates at 1800 rpm through five different load points in diesel and dual fuel operating modes. Crank angle resolved high speed combustion pressure data is obtained and analyzed. The natural gas substitution values tested are representative of standard dual fuel tuning, with a maximum diesel displacement of 70%. Data for thermal efficiency, combustion stability, in-cylinder pressure and net heat release rate are also presented in this study. In addition, fuel consumption and pollutant emissions are measured. Elevated CO and HC emissions are observed at low loads for dual fuel operation. Overall, CO and unburned HC emissions increase for dual fuel operation. However, the average levels of PM and NOx substantially decreases. A series of natural gas and injection timing sweep are conducted to optimize the combustion and emission in dual fuel engine. To understand the location of emissions inside the cylinder, a model study of a natural gas-diesel dual fuel combustion and emission is performed using the commercial CONVERGE CFD code. A reduced chemical kinetic mechanism with 86 species and 393 reactions for n-heptane, methane, ethane and propane is used. A preliminary hypothesis for these emissions is formulated based on the values of experiment equivalence ratio. Findings indicate that a large amount of CO and HC emissions in dual fuel engines are mainly located on the cylinder wall and nozzle area. High temperatures are not able to propagate through the lean mixture of natural gas and air in dual fuel engine hence high unburned fuel trapped at wall. It is concluded that dual fuel engines are capable of reducing emissions and cost saving (through diesel displacement up to 70%) in diesel fuel engines. CO and unburned HC can be reduced with the application of a dual fuel optimization map. Further investigation using oxidation catalyst is recommended in order to meet with emission regulations.
Open Access
Integrated techno-economic analysis and life cycle assessment of emerging technologies with temporal resolution
(Colorado State University. Libraries, 2020) Sproul, Evan, author; Quinn, Jason C., advisor; Marchese, Anthony J., committee member; Jathar, Shantanu H., committee member; Denning, A. Scott, committee member
Techno-economic analysis (TEA) and life cycle assessment (LCA) are analytical tools used to quantify the economic and environmental performance of emerging technologies. TEA and LCA help guide the development of these technologies by identifying areas where additional research will significantly reduce economic costs and environmental impacts. Although often used in tandem, TEA and LCA output separate results that rely upon disconnected metrics. When considering the impact of time, the disconnect between TEA and LCA methods is critical and can significantly impact results. In this dissertation, three phases of research are conducted to illustrate and reconcile the disconnect between TEA and LCA. In the first phase, standard TEA and LCA methods are used to evaluate the economic and environmental performance of natural rubber derived from guayule (Parthenium argentatum). This evaluation is used to identify the strengths and weaknesses of interpreting disconnected TEA and LCA results. In the second phase, two new methods are created to overcome this disconnect by integrating temporally resolved TEA and LCA. These methods are applied to electric power and guayule rubber production to highlight the impacts of integrating temporally resolved TEA and LCA. In the third phase, integrated TEA and LCA is used to perform a deep-dive evaluation on low-emissions technology options for natural gas combined cycle power plants. In this phase, TEA and LCA with temporal resolution are used to identify cost targets for biomethane, carbon capture and storage (CCS), and bioenergy with CCS (BECCS) under different emissions pricing scenarios. Taken together, the three phases of research in this dissertation represent a wide range of applications and methodologies, each with varying objectives and complexity. Understanding the details of these approaches will help guide future analysis where economic costs, environmental impacts, and time are important considerations in technological development.
Open Access
Investigation and applications of current and novel sustainability sciences
(Colorado State University. Libraries, 2020) DeRose, Katherine K., author; Quinn, Jason C., advisor; Marchese, Anthony J., committee member; Jathar, Shantanu, committee member; Peebles, Christie, committee member
Engineering-based sustainable solutions are required to ensure continued access to energy, food and clean water for a growing population. Techno-economic analysis and life cycle assessment provide a means of evaluating emerging technologies to determine if they can economically and sustainably provide solutions to current and future resource demands. Concurrently, performance targets can be identified to help drive technology forward in a sustainable fashion. A major advantage of sustainability analyses is the ability to perform early-stage technology evaluation prior to intensive research investment. The application of these techniques can be applied to a variety of technologies including renewable bio-based fuels. It is also necessary to understand the limitations of these sustainability sciences to properly interpret analysis results. This work focuses on the applications of sustainability sciences to multiple technologies including foundational investigation of the methodology behind assessments. The first technology evaluation showcases the iterative nature and relationship between sustainability sciences and research for a novel biofuel conversion process using algae as a feedstock. The second technology evaluation seeks to improve sustainability metrics of the widespread corn-ethanol process; and is also used as a case study to identify limitations in current sustainability sciences. The final technology evaluation is a novel application of sustainability sciences to identify technology solutions for environmental disruptions. Microalgae has been a feedstock of interest for renewable fuels production, but the technology remains impeded due to high growth costs. Most research has been focused on increasing biomass productivity and lipid content and/or reducing capital and operation costs associated with traditional growth systems. An alternative approach is to consider an entirely new growth method; attached-growth systems. Sustainability modeling was used to identify the optimal processing opportunities for the production of renewable fuels from algae grown in this method through the use of economic and environmental analyses. Results indicated that ash reduction, energy intensive processing and high growth costs needed to be addressed to improve economic viability. A secondary effort focused on advancing the research and modelling to further refine results based on this focus. Results show minimum fuel selling prices ranging between $9.13 to $31.22 per gallon of gasoline equivalent, dependent on scenario and process assumptions. Sustainability analyses can also be applied to improve current technologies. Corn ethanol represents a mature technology with a long production history as a first-generation alternative fuel but has been widely criticized for high production costs and only marginal sustainability improvements over traditional petroleum-based fuels. One approach for improving these metrics is to focus on increased utilization of co-products through additional processing. Sustainability analysis results indicate an additional co-product fermentation process may be considered as a value-add for refiners but is dependent on economic and product market assumptions. This process was also used as a case study to explore how life cycle methodology affects environmental impact results. Life cycle assessment (LCA) results have a broad variability with well-to-pump results ranging between 42 to 210 g CO2-eq MJ fuel-1, dependent on co-product allocation methodology. This variability within the results can affect a product's ability to meet environmental standards, such as the Renewable Fuel Standard, and represents a critical area for improved methodological guidance. In addition to technology, sustainability sciences can also be applied to identify economically viable solutions for environmental disruptions such as harmful algae blooms (HAB's). HAB's affect both fresh and saltwater bodies around the world, causing a variety of environmental and economic damages to surrounding ecosystems and communities. The primary driver of HAB's is eutrophication, or excess nutrients in the water, and the principal approach to mitigating HAB's is reducing nutrients before they collect en masse downstream. Technology solutions can be employed to remove nutrients from waterways, but feasibility of technology deployment is dependent on the economic viability. Applications of sustainability sciences allows researchers to identify potential solutions to reduce HAB events which are both effective and economically viable. Results show that on average, Lake Erie communities lose $142 M (± $29M) year-1 from HAB's without mitigation. Use of attached-algae systems show an average savings of $12-42M per year from HAB mitigation and represent the most promising technology investigated. Attached-algae systems are the only nutrient reduction technology to show net-positive cash flow when compared with traditional nutrient removal systems. This research dissertation outlines tasks associated with the different applications of sustainability sciences. First, sustainability analyses are used to identify current research roadblocks associated with a technology and are used to identify optimal processing options and provide feedback to researchers to improve these metrics. Next, the tool set was adapted to a novel biorefining process and used to evaluate a value-add proposition for a current technology and showcase current limitations of LCA methodology. And finally, they were leveraged to create a framework for evaluating costs and benefits of technology adoption for pro-active mitigation of environmental disruptions.
Open Access
Life cycle and technoeconomic analysis of microalgae-based biofuels
(Colorado State University. Libraries, 2014) Batan, Liaw Yih Der, author; Bradley, Thomas H., advisor; Willson, Bryan D., advisor; Marchese, Anthony J., committee member; Graff, Gregory D., committee member; Paustian, Keith, committee member
Microalgae are an appealing feedstock for production of biofuels due to their high productivity compared to terrestrial plant-based feedstocks, and their relative tolerance of low quality land and water. Despite these potential benefits, there are technological, environmental and economic challenges that must be overcome to enable commercialization of any microalgae-to-biofuels process. Due to the relative immaturity of the field, assessments of the environmental performance, scalability and economic performance of microalgae-based biofuels are highly uncertain, data poor, and incomparable across technologies. This dissertation seeks to study these aspects of microalgae-based biofuels so as to provide models of increased utility for technical design, investment planning, and achieving policy-level objectives. This work is divided in three primary research efforts. First, this research develops an integrated life cycle assessment of the microalgae to biofuels process using a detailed engineering model derived from a pilot-scale photobioreactor system. The life cycle assessment quantifies and compares energy consumption, greenhouse gas emissions, and scalability of the biofuel life cycle. Second, this work defines the water footprint for a photobioreactor-based biofuel production system with geographical and temporal resolution. The water footprint (WF) of microalgae biofuel is comprehensively assessed using a combined process and economic input-output lifecycle analysis method, using blue, green and lifecycle WF metrics, four different fuel conversion pathways, and 10 continental US locations with high productivity yields. Finally, a technoeconomic analysis of the baseline enclosed photobioreactor microalgae to biofuels system is performed with stochastic economic risk assessment. This section provides a range of probabilities of economic success based on the sensitivity of the microalgae-to-biofuel process to the variable economic variables and scenarios. Based on the results of these integrated assessments of microalgae biofuels, this study communicates an improved understanding of the economic and environmental performance of microalgae biofuels and their characteristics compared to petroleum and biofeedstock-based biofuels.
Open Access
Measurement of ammonia emission from agricultural sites using open-path cavity ring-down spectroscopy and wavelength modulation spectroscopy based analyzers
(Colorado State University. Libraries, 2018) Shadman, Soran, author; Yalin, Azer P., advisor; Marchese, Anthony J., committee member; Olsen, Daniel B., committee member; Ham, Jay, committee member
Agricultural activities and animal feedlot operations are the primary sources of emitted ammonia into the atmosphere. In the US, 4 Tg of ammonia is emitted every year into the atmosphere which ~%75 of that is due to these major sources. Ammonia is the third most abundant nitrogen containing species in the atmosphere and it has important impacts on atmospheric chemistry, health, and the environment. It is a precursor to the formation of aerosols and its deposition in pristine and aquatic systems leads to changes in ecosystem properties. Quantifying the dry deposition rate of ammonia in the first few kilometers of feedlots is crucial for better understanding the impacts of livestock and agricultural operations on environment. Therefore, fast, precise, and portable sensors are needed to quantify ammonia emission from its major sources. Absorption spectroscopy is a reliable technique by which compact and sensitive sensors can be developed for ammonia (and other gaseous species) detection. An open-path absorption spectroscopy based sensor allows ambient air to flow directly through its measurement region which leads to high-sensitivity and fast-response measurements. In this study, two open-path absorption based ammonia sensors using two techniques are developed: cavity ring-down spectroscopy (CRDS) and wavelength modulation spectroscopy (WMS). The CRDS and WMS based sensors show the sensitivity of ~1.5 ppb (at 1 second) and ~4 ppb (at 1 second), respectively. In both sensors, a quantum cascade laser (QCL) is utilized as the light source to cover the strongest absorption feature of ammonia in the mid-infrared (MIR) spectral region. It is the first demonstration of an open-path CRDS based sensor working in mid-infrared MIR, to our knowledge. The WMS based sensor developed in this study is low power (~25 W) and relatively lightweight (~4 kg). The low power consumption and compact size enables the sensor to be deployed on a commercialized unmanned aerial system (UAS) for aerial measurements. The combination of this sensor and another compact CRDS based methane sensor is used for simultaneous measurements of ammonia and methane (ground based and aerial). Methane is another important species emitted from the feedlots with a long lifetime (~10 years). It is nonreactive and thus not lost by dry deposition. Therefore, methane concentration is only influenced by dispersion while the ammonia concentration is affected by both deposition and dispersion. The dry deposition of ammonia nearby the concentrated animal feeding operations (CAFOs), as one of the major sources of ammonia, can be determined by measuring the decrease in the [NH3]/[CH4] ratio downwind.
Open Access
Methods for advancing automobile research with energy-use simulation
(Colorado State University. Libraries, 2014) Geller, Benjamin M., author; Bradley, Thomas H., advisor; Marchese, Anthony J., committee member; Olsen, Daniel B., committee member; Young, Peter M., committee member
Personal transportation has a large and increasing impact on people, society, and the environment globally. Computational energy-use simulation is becoming a key tool for automotive research and development in designing efficient, sustainable, and consumer acceptable personal transportation systems. Historically, research in personal transportation system design has not been held to the same standards as other scientific fields in that classical experimental design concepts have not been followed in practice. Instead, transportation researchers have built their analyses around available automotive simulation tools, but conventional automotive simulation tools are not well-equipped to answer system-level questions regarding transportation system design, environmental impacts, and policy analysis. The proposed work in this dissertation aims to provide a means for applying more relevant simulation and analysis tools to these system-level research questions. First, I describe the objectives and requirements of vehicle energy-use simulation and design research, and the tools that have been used to execute this research. Next this dissertation develops a toolset for constructing system-level design studies with structured investigations and defensible hypothesis testing. The roles of experimental design, optimization, concept of operations, decision support, and uncertainty are defined for the application of automotive energy simulation and system design studies. The results of this work are a suite of computational design and analysis tools that can serve to hold automotive research to the same standard as other scientific fields while providing the tools necessary to complete defensible and objective design studies.
Open Access
Microalgae to biofuels evaluation through experimentally validated models
(Colorado State University. Libraries, 2011) Quinn, Jason, author; Bradley, Thomas H., advisor; Marchese, Anthony J., committee member; Willson, Bryan D., committee member; Siller, Thomas J., committee member
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Open Access
Performance and plume characterization of a laboratory krypton Hall thruster
(Colorado State University. Libraries, 2020) Andreano, Thomas Malachi, author; Williams, John D., advisor; Marchese, Anthony J., committee member; Roberts, Jacob L., committee member
Hall thruster research has been in progress at the CSU Electric Propulsion and Plasma Engineering (CEPPE) lab for the past decade, however, a full performance and plasma plume characterization has not been conducted with the laboratory Hall thruster available, which recently was modified to be configured as magnetically shielded as well as non-magnetically shielded. Additionally, heaterless cathode geometries that could benefit scaling of Hall thrusters to either much larger or much smaller designs have been undergoing development at the CEPPE lab. One of these cathodes, named the postage stamp, was designed to mount to the outer pole piece on the front of the thruster in the seperatrix of the magnetic field, and fits in the space between the outer pole piece and the backplate of the thruster. To further the research on Hall thrusters at CSU, a baseline of the laboratory thruster performance is necessary, and performance characterization of the operation using different cathodes is necessary to further the cathode design. To these ends, performance of the thruster was characterized with: (1) the center mounted cathode, providing a baseline for all future Hall thruster research at the CEPPE lab, (2) with the postage stamp cathode, to determine the potential performance differences between operation with the two cathodes, and (3) in the magnetically shielded configuration, to verify proper operation and investigate any potential performance differences compared to the traditional configuration. Thrust measurement, along with data from an Electrostatic Analyzer (ESA), ExB probe, and Faraday probe were collected to determine the performance characteristics of the thruster as well as the characteristics of the ion beam in each of the three cases outlined above. Additionally, a preliminary study of an anomalous operation mode providing higher than usual performance was conducted using these probes, as well as a combined ESA/ExB called the EVADER probe.
Open Access
Synthesis, properties, and suitability of various oxymethylene ethers for compression ignition fuels
(Colorado State University. Libraries, 2023) Lucas, Stephen P., author; Windom, Bret, advisor; Foust, Thomas, committee member; Reardon, Kenneth, committee member; Marchese, Anthony J., committee member
Compression ignition (CI) engines are currently the most common prime mover for medium and heavy duty vehicles; these engines contribute roughly a quarter of US greenhouse gas emissions from transportation, and even higher percentages of particulate and nitrogen oxide emissions. As a result, there have been significant efforts made to reduce these emissions, particularly through selection of low-emissions alternative fuels. Oxymethylene ethers (OMEs) are a class of molecule, typically structured R-O-(CH2O)n-R', which have been considered as a possible blendstock in CI fuels for the goal of soot reduction. Generally, past work has focused on methyl-terminated OMEs, CH3-O-(CH2O)n-CH3, which by virtue of containing no C--C bonds, produce negligible soot. These molecules show significant reductions in soot emission from engines when blended in moderate to high ratios with traditional diesels, however, they have been shown to have inferior physical properties and poor compatibility with some legacy systems. Recent theoretical work has shown that OMEs with non-methyl alkyl groups may have superior performance, albeit at the cost of increased soot formation. In this work, a variety of OMEs with terminating alkyl groups from methyl to butyl are considered for their suitability as CI fuels. The synthesis of these extended OMEs is studied, including formation of n=1 OMEs from common chemical sources, and extension of the chain length to heavier molecules, via reactions over acidic ion exchange resins. Following the synthesis, the properties of these OMEs are studied with respect to their engine applicability. It is found that heavier (propyl- and butyl-terminated) OMEs have superior properties for diesel compatibility, particularly in reactivity, volatility, and water solubility. Extended-alkyl OMEs are found to have higher soot production than methyl-terminated OMEs, but remain superior to diesel soot production on a per-unit-energy basis. A sample of a butyl-terminated OME mixture, n=2-4, is selected as the ideal OME blend for close compatibility with legacy diesel systems. This mixture is blended with certified diesel and tested for ASTM D975 compatibility, passing all required tests but lubricity; decreased heat of combustion is observed but not governed by the diesel standard. Fundamental combustion tests of various mid-weight OMEs are performed in a rapid compression machine, where it is shown that low-temperature chemistry causes a region of decreased dependence of ignition delay on temperature, consistent with methyl-terminated OME behavior. An isopropyl-terminated OME is observed to have low reactivity compared to other OMEs; this fuel is investigated via further rapid compression machine testing and CFR engine testing. It is found that this OME has strong negative-temperature-coefficient ignition behavior - a first for OMEs - and has reactivity lower than other OMEs, but insufficient for direct spark ignition engine testing.
Open Access
Time integration for complex fluid dynamics
(Colorado State University. Libraries, 2021) Christopher, Joshua C., author; Gao, Xinfeng, advisor; Guzik, Stephen M., committee member; Marchese, Anthony J., committee member; Bangerth, Wolfgang, committee member
Efficient and accurate simulation of turbulent combusting flows in complex geometry remains a challenging and computationally expensive proposition. A significant source of computational expense is in the integration of the temporal domain, where small time steps are required for the accurate resolution of chemical reactions and long solution times are needed for many practical applications. To address the small step sizes, a fourth-order implicit-explicit additive Runge-Kutta (ARK4) method is developed to integrate the stiff chemical reactions implicitly while advancing the convective and diffusive physics explicitly in time. Applications involving complex geometry, stiff reaction mechanisms, and high-order spatial discretizations are challenged by stability issues in the numerical solution of the nonlinear problem that arises from the implicit treatment of the stiff term. Techniques for maintaining a physical thermodynamic state during the numerical solution of the nonlinear problem, such as placing constraints on the nonlinear solver and the use of a nonlinear optimizer to find valid thermodynamic states, are proposed and tested. Verification and validation are performed for the new adaptive ARK4 method using lean premixed flames burning hydrogen, showing preservation of 4th-order error convergence and recovery of literature results. ARK4 is then applied to solve lean, premixed C3H8-air combustion in a bluff-body combustor geometry. In the two-dimensional case, ARK4 provides a 70× speedup over the standard explicit four-stage Runge-Kutta method and, for the three-dimensional case, three-orders-of-magnitude-larger time step sizes are achieved. To further increase the computational scaling of the algorithms, parallel-in-time (PinT) techniques are explored. PinT has the dual benefit of providing parallelization to long temporal domains as well as taking advantage of hardware trends towards more concurrency in modern high-performance computing platforms. Specifically, the multigrid reduction-in-time (MGRIT) method is adapted and enhanced by adding adaptive mesh refinement (AMR) in time. This creates a space-time algorithm with efficient solution-adaptive grids. The new MGRIT+AMR algorithm is first verified and validated using problems dominated by diffusion or characterized by time periodicity, such as Couette flow and Stokes second problem. The adaptive space-time parallel algorithm demonstrates up to a 13.7× speedup over a time-sequential algorithm for the same solution accuracy. However, MGRIT has difficulties when applied to solve practical fluid flows, such as turbulence, governed by strong hyperbolic partial differential equations. To overcome this challenge, the multigrid operations are modified and applied in a novel way by exploiting the space-time localization of fine turbulence scales. With these new operators, the coarse-scale errors are advected out of the temporal domain while the fine-scale dynamics iterate to equilibrium. This leads to rapid convergence of the bulk flow, which is important for computing macroscopic properties useful for engineering purposes. The novel multigrid operations are applied to the compressible inviscid Taylor-Green vortex flow and the convergence of the low-frequency modes is achieved within a few iterations. Future work will be focused on a performance study for practical highly turbulent flows.
Open Access
Waste heat driven turbo-compression cooling
(Colorado State University. Libraries, 2018) Garland, Shane Daniel, author; Bandhauer, Todd M., advisor; Marchese, Anthony J., committee member; Carlson, Kenneth H., committee member
Waste heat recovery systems utilize exhaust heat from power generation systems to produce mechanical work, provide cooling, or create high temperature thermal energy. One waste heat recovery application is to use the exhaust heat from a Natural Gas Combined Cycle Power Plant (NGCC) to drive a heat activated cooling system that can offset a portion of the plant condenser load. There are several heat activated cooling systems available including absorption, adsorption, ORVC, and ejector, but each has disadvantages. One system that can overcome the disadvantages of typical heat activated cooling systems is a turbo-compression cooling system (TCCS). In this system, the exhaust heat enters an organic Rankine cycle at the boiler and vaporizes the fluid that passes through a turbine. The turbine power is directly transferred to a compressor via a hermetically sealed shaft that is made possible by a magnetic coupling. The compressor operates a vapor-compression system which provides a cooling effect in the evaporator. The hermetic seal between the turbine and compressor allows for two separate fluids on the power and cooling cycles, which maximizes the efficiency of the turbine and compressor simultaneously. This study presents a thermodynamic modeling approach that makes system performance predictions for the baseline design case, and for off-design performance conditions. The off-design modeling approach uses turbo-compressor performance maps and a heat exchanger UA scaling methodology to accurately simulate system operation for a broad range of temperatures and cooling loads. A 250 kWth cooling capacity TCCS was constructed and tested to validate the modeling approach. The test facility simulates a 138:1 scaled NGCC power plant configuration in which the TCCS extracts 106°C waste heat from the flue gases and produces a cooling effect that offsets a portion of the NGCC condenser load. The design target for the test facility was to achieve a COP of 2.1 while chilling water from 17.2°C to 16°C at an ambient temperature of 15°C. Although the final design point was not tested for this study due to facility limitations, the off-design performance methodology was utilized to predict the performance for an ambient condition of 27.5°C and power and cooling cycle mass flow rate range between 0.35 kg s-1 - 0.5 kg s-1 and 0.65 kg s-1 – 0.85 kg s-1, respectively. The comparison between the experimental and modeling data suggested strong correlation over the data range presented with a maximum error in COP of only 2.0% among the selected data points. Future experimental data over a larger range of ambient temperatures and system conditions is suggested to further validate the system modeling. Regardless, the results in the present study show that the TCCS compares favorably with other heat activated cooling systems.