Browsing by Author "Quinn, Jason, committee member"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
Item Open Access Applying model-based systems engineering to architecture optimization and selection during system acquisition(Colorado State University. Libraries, 2018) LaSorda, Michael, author; Sega, Ronald M., advisor; Borky, Mike, advisor; Bradley, Tom, committee member; Quinn, Jason, committee memberThe architecture selection process early in a major system acquisition is a critical step in determining the overall affordability and technical performance success of a program. There are recognized deficiencies that frequently occur in this step such as poor transparency into the final selection decision and excessive focus on lowest cost, which is not necessarily the best value for all of the stakeholders. This research investigates improvements to the architecture selection process by integrating Model-Based Systems Engineering (MBSE) techniques, enforcing rigorous, quantitative evaluation metrics with a corresponding understanding of uncertainties, and stakeholder feedback in order to generate an architecture that is more optimized and trusted to provide better value for the stakeholders. Three case studies were analyzed to demonstrate this proposed process. The first focused on a satellite communications System of Systems (SoS) acquisition to demonstrate the overall feasibility and applicability of the process. The second investigated an electro-optical remote sensing satellite system to compare this proposed process to a current architecture selection process typified by the United States Department of Defense (U.S. DoD) Analysis of Alternatives (AoA). The third case study analyzed the evaluation of a service-oriented architecture (SOA) providing satellite command and control with cyber security protections in order to demonstrate rigorous accounting of uncertainty through the architecture evaluation and selection. These case studies serve to define and demonstrate a new, more transparent and trusted architecture selection process that consistently provides better value for the stakeholders of a major system acquisition. While the examples in this research focused on U.S. DoD and other major acquisitions, the methodology developed is broadly applicable to other domains where this is a need for optimization of enterprise architectures as the basis for effective system acquisition. The results from the three case studies showed the new process outperformed the current methodology for conducting architecture evaluations in nearly all criteria considered and in particular selects architectures of better value, provides greater visibility into the actual decision making, and improves trust in the decision through a robust understanding of uncertainty. The primary contribution of this research then is improved information support to an architecture selection in the early phases of a system acquisition program. The proposed methodology presents a decision authority with an integrated assessment of each alternative, traceable to the concerns of the system's stakeholders, and thus enables a more informed and objective selection of the preferred alternative. It is recommended that the methodology proposed in this work is considered for future architecture evaluations.Item Open Access Expanding the knock/emissions limits for the realization of ultra-low emissions, high-efficiency heavy-duty natural gas engines(Colorado State University. Libraries, 2023) Rodriguez Rueda, Juan Felipe, author; Olsen, Daniel B., advisor; Windom, Bret, committee member; Baker, Daniel, committee member; Quinn, Jason, committee memberHeavy-duty on-highway natural gas (NG) engines are a promising alternative to diesel engines to reduce greenhouse gas and harmful pollutant emissions if the limitations (knock and misfire) for achieving diesel-like efficiencies are addressed. This study shows innovative technologies for developing high-efficiency stoichiometric, spark-ignited (SI) natural gas engines. To develop the base knowledge required to reach the desired efficiency, a Single Cylinder Engine (SCE) is the most effective platform for acquiring reliable and repeatable data. An SCE test cell was developed using a Cummins 15-liter six-cylinder heavy-duty engine block modified to fire one cylinder (2.5-liter displacement). A Woodward Large Engine Control Module (LECM) is integrated to permit real-time advanced combustion control implementation. Fixed location of 50% burn and Controlled End Gas Auto-Ignition (C-EGAI) were used to define the ignition timing. C-EGAI allows operation with an optimized fraction of end gas auto-ignition combustion. Intake and exhaust characteristics, fuel composition, and exhaust gas recirculated substitution rate (EGR) are fully adjustable. A high-speed data acquisition system acquires in-cylinder, intake, and exhaust pressure for combustion analysis. Further development includes advanced control methodologies to maintain stable operation and higher dilution tolerance. Controlled end-gas autoignition (C-EGAI) is used as a combustion control strategy to improve efficiency. A Combustion Intensity Metric (CIM) is used for ignition control while operating the engine under C-EGAI. During the baseline testing of the developed SCE test cell, effective control of intake manifold pressure, exhaust manifold pressure, engine equivalence ratio, speed, torque, jacket water temperature, and oil temperature was demonstrated. The baseline testing shows reliable and consistent results for engine thermal efficiency, indicated mean effective pressure (IMEP), and coefficient of variance of the IMEP over a wide range of operating conditions. High Brake Thermal Efficiency (BTE) was achieved using improved hardware and a high EGR rate. Due to the correlation of CIM to the fraction of EGAI (f-EGAI), CIM was used as the reference variable to implement C-EGAI. Achieving conditions of C-EGAI allowed for the utilization of high EGR at high IMEP without inducing knock. The operation of the engine under these conditions showed peak brake thermal efficiency above 46% using an EGR ratio of 30% The work described proves the concept of using new and innovative control algorithms and CFD-optimized combustion chamber designs, allowing ultra-high efficiency and low emissions for NG ICE's heavy-duty on-road applications.Item Open Access Experimental evaluation of stack testing methods for accurate VOC measurement(Colorado State University. Libraries, 2019) King, Brenna Allison, author; Olsen, Daniel, advisor; Quinn, Jason, committee member; Carter, Ellison, committee memberThere are more than 1,400 natural gas compressor stations that utilize large-bore, two-stroke natural gas engines in the United States to transport natural gas through pipelines across the country. Because of the long operating lives associated with these engines, it is important for emissions to be monitored and technology to be improved to ensure the engines are meeting current emissions standards. One emission class that is currently regulated by the Environmental Protection Agency (EPA) is volatile organic compounds (VOCs). VOCs are defined as non-methane, non-ethane hydrocarbons and have negative environmental effects, especially in the formation of ozone and fine particulates that create smog. The combination of a Gas Chromatograph (GC) and a Flame Ionization Detector (FID) can be used to measure methane, ethane, and VOCs. The use of a GC/FID to quantify hydrocarbon concentration is in compliance with EPA Method 18/25A. In some cases, this approach is mandated by regulatory bodies. The Fourier Transform Infrared Spectrometer (FTIR) can also be used to measure VOCs in engine exhaust gas, following EPA Method 320. However, there is concern that Method 320 is not as accurate as Method 18/25A. The main objective of this research is to provide data and analysis with both measurement methods from different engine types, conditions, and fuel quality to determine whether Method 320 is acceptable for VOC quantification. iii Exhaust gas was sampled from engines of different types and configurations: the GMV-4 lean burn testing with open chamber spark ignition, pre-combustion chamber ignition, and high-pressure fuel injection with electronic fuel valves and the Caterpillar 3304 rich burn testing with a three-way catalyst. For the GMV-4 configurations, an ignition timing sweep was performed, including retarding and advancing ignition timing from the nominal 18°aTDC. In addition, fuel ethane and fuel higher hydrocarbons were added to the natural gas fuel supply separately to determine the effects fuel variability has on emissions and engine performance. For the Caterpillar 3304 configuration, only an ignition timing sweep was performed. It was concluded that the HP 5890 Series II GC utilizing EPA Method 18/25a is the most accurate method for VOC quantification. Both the Gasmet and MKS FTIRs (EPA Method 320) overestimate total VOC concentration compared to the HP GC by approximately 18 percent and 12 percent, respectively. However, in most cases the differences were within uncertainty bounds. A common process currently used for VOC quantification, which subtracts the methane and ethane measurements from the MKS FTIR (utilizing EPA Method 320) from the THC measurement from the Siemens 5-Gas analyzer, is not an accurate method as it creates large uncertainty up to 193 percent and overestimates total VOC concentration by nearly 100 percent relative to the HP GC.Item Open Access Experimental investigation of an advanced organic Rankine vapor compression chiller(Colorado State University. Libraries, 2022) Grauberger, Alex Michael, author; Bandhauer, Todd, advisor; Quinn, Jason, committee member; Windom, Bret, committee member; Sharvelle, Sybil, committee memberThermally driven chilling technologies convert heat into cooling. These systems can support increasing cooling demands using waste heat in a variety of applications. Commercial thermally driven chilling technologies suffer from several implementation challenges, including high capital costs, limited equipment lifecycles, rigid working principles, and large physical formats, and thus are not implemented widely. Organic Rankine vapor compression cooling systems are a pre-commercial technology which can address the limitations of commercial alternatives. Organic Rankine vapor compression cooling systems couple an organic Rankine power generation cycle to a standard vapor compression chilling cycle. These systems can use benign, pressurized refrigerants as working fluids which allows for reduced heat exchanger costs over commercial thermally driven alternatives without environmentally impactful fugitive emissions. Refrigerants are released from cooling technologies during charging, leaking connections, and/or improper/unregulated disposal. Furthermore, the coupling of the two individual cycles allows the use of high-speed compression and expansion machinery as well as multiple methods of heat recuperation. High-speed fluid machinery and heat recuperation strategies reduce the format and cost of the technology while simultaneously improving the longevity and operational flexibility. Current organic Rankine vapor compression efforts are limited from an absence of experimental validation. This study aims to fill this research gap through investigating a prototype organic Rankine vapor compression system enhanced with a high-speed, centrifugal turbo-compressor, sub cycle and cross cycle heat recuperation, compact heat exchanger technologies, and benign, next-generation refrigerants at an industry-relevant scale of 300 kW. A thermodynamic model was created and a system heat-to-cooling coefficient of performance (COP) of 0.65 was simulated with 91°C liquid waste heat, 30°C condenser coolant, and 7°C chilled water delivery where a 5°C inlet to outlet temperature difference was specified for each stream. A full-scale prototype was fabricated and tested following standards for performance rating of commercial water chilling technologies to validate the performance simulation. Experimental testing of the prototype yielded a thermal COP of 0.56 and a cooling duty of 264 kW under its baseline operating conditions. The baseline test conditions were identical to the simulated conditions except the temperature difference across the condensers, which was 1.7°C greater due to a 25.6% lower condenser coolant flowrate. The lower condenser coolant flowrate, a vapor compression condenser refrigerant outlet vapor mass quality of 6.2% instead of the modeled 1°C of subcooling, and elevated system pressure losses limited the efficiency and cooling duty of the prototype over the simulated values. A scenario analysis on the test data was complete to show the prototype could surpass the simulated performance prediction with a COP of 0.66 at 300 kW of cooling if the operational limitations associated with prototype were corrected. This performance is competitive with commercial single-effect absorption systems and is possible because the turbomachinery efficiencies were high. The isentropic efficiency values for the turbine and compressor were 76.7% and 84.8% respectively at the baseline conditions during experimentation and the two devices had a 100% power transmission efficiency within experimental error. Following the assessment of baseline performance, operational characteristics of the technology were quantified at off-design boundary conditions and normalized to those of the baseline to identify performance trends. It was shown that prototype thermal performance generally improved with increasing waste heat supply temperature, increasing chilled water delivery temperature, decreasing condenser coolant temperature, and decreasing chilling duty. These trends are consistent with performance simulations in literature. However, performance improvements at off-design operation were often challenged by variations in turbine and compressor efficiency as well as the efficacy of heat recuperation strategies. Such changes to component performance characteristics at varying boundary conditions have not been previously quantified in practice and, thus, have historically been neglected in analytical investigations of organic Rankine vapor compression systems. Understanding the off-design component performance characteristics allows for the creation of validated organic Rankine vapor compression performance models. Such models will be critical to understanding the true energy savings potential of organic Rankine vapor compression systems as they are continuously investigated.Item Open Access In-vehicle validation of energy consumption modeling and simulation(Colorado State University. Libraries, 2020) DiDomenico, Gabriel, author; Bradley, Thomas, advisor; Quinn, Jason, committee member; Pasricha, Sudeep, committee memberThe Colorado State University (CSU) Vehicle Innovation Team (VIT) participated in the first Department of Energy (DOE) Advanced Vehicle Technology Competitions (AVTC) in 1988. Since then, it has participated in the next iterations of the competition as well as other advanced vehicle technology projects. This study aims to validate the team's mathematical modeling and simulation of electrical energy consumption of the EcoCAR 3 competition (academic years 2014-2018) as well as the testing methods used for validation. First, baseline simulation results are obtained by simulating a 0-60 mph wide open throttle (WOT, or 100% APP) acceleration event (AE) with the product being the electrical energy economy in Wh/mi. The baseline model (representing the baseline control strategy and vehicle parameters) is also simulated for 0-40 mph and 0-20 mph AEs. These tests are replicated in the actual vehicle, a 2016 P2 PHEV Chevrolet Camaro entirely designed and built by CSU's VIT. Next, the same AEs are again tested with a changed acceleration rate due to the APP being limited to 45%. The velocity profiles from these tests are used as feedback for the model and the tests are replicated in simulation. Finally, the baseline model is altered in 3 additional ways in order to understand their effect on electrical energy consumption: the mass is increased, then the auxiliary low voltage (LV) load is increased and then the transmission is restricted to only 1 gear. These simulations are again replicated in-vehicle in order to validate the model's capability in predicting changes in electrical energy consumption as certain vehicle parameters are changed. This study concludes that model is able to predict these changes within 6.5%, or ±30.2 Wh/mi with 95% confidence.Item Open Access Maintaining leachate flow through a leach bed reactor during anaerobic digestion of high-solids cattle manure(Colorado State University. Libraries, 2018) Lewis, Matthew A., author; Sharvelle, Sybil, advisor; Grigg, Neil, committee member; Quinn, Jason, committee memberTo address the accumulation of high-solids cattle manure (HSCM) found at many of the state's Animal Feeding Operations (AFOs), researchers at CSU have developed a Multi-Stage Anaerobic Digester (MSAD). The MSAD system consists of a leach bed reactor (LBR), a compositing tank, and a fixed-film methanogenic reactor. The LBR is a critical part of the MSAD system since hydrolysis can be a rate-limiting step in the anaerobic digestion of HSCM (Hinds 2015; Veeken and Hamelers 1999). To ensure that hydrolysis is occurring properly within the reactor, leachate injection and reactor operation must proceed in a manner that facilitates uniform distribution of leachate through the manure waste bed. Since the leachate must be recirculated through the LBR for the entirety of the batch digestion time, any phenomena that disrupt the duration or uniformity of leachate distribution must be addressed. The overarching goal of this thesis project was to improve the hydraulic performance of the LBR stage of the MSAD. This research included a multi-criterion decision analysis (MCDA) to assess unique design aspects of the MSAD relative to other technologies, construction and operation of a prototype LBR, and the development of an experimentation strategy to assess mechanism of hydraulic failure in the LBR. The MSAD system was compared to four other high-solids anaerobic digester technologies using a MCDA. The purpose of this comparison was to identify unique design features of the MSAD technology compared to other high-solids anaerobic digestion technologies to inform the focus of future design and research activities. The technologies were rated and evaluated for the following criteria: operational requirements, impact of hydraulic failure, capital requirements, operational control, feedstock technology fit, and process efficiency. The scores ranged from 2.9 to 3.7 out of 5 possible points. Under equal criteria weighting, the MSAD system received the highest rating with a score of 3.7. The MSAD system received high ratings due to its strong hydraulic performance, operational control, and process efficiency. Knowledge gained through laboratory and prototype-scale LBR experimentation was used to establish possible improvements to LBR design. The primary improvement to the LBR was the modification from a downflow to an upflow configuration. A prototype LBR was operated in the upflow configuration to facilitate longer durations of undisrupted leachate permeation. In addition, it was determined that leachate injection spacing should be studied further as results from operation of the prototype LBR suggested that higher volatile solids reduction occurred closer to the leachate influent manifold. Column experiments and prototype operation showed some successful operation of LBRs for treating HSCM. However, hydraulic failures due to clogging and preferential pathway formation were observed. Due to the continued risk of hydraulic failure, further research was needed to understand mechanisms for hydraulic failure and to determine approaches to overcome these issues. At commercial scale, hydraulic failure of LBRs would result in decreased energy and agricultural product output and increased operating costs. Since commercial processes rely on reproducible results, a high degree of LBR reliability is required to achieve technical and economic feasibility. Therefore, control over the hydraulic performance of LBRs is critical for commercialization of the MSAD system. To this end, an experimentation strategy was developed, with the goal to elucidate the mechanisms behind hydraulic failures occurring in the LBR. To evaluate these mechanisms, the experimentation strategy recommends the use of electrical resistivity tomography (ERT) to render visualizations of leachate distribution throughout the waste bed. Further characterization of the pore space network geometry at the microscale using either Magnetic Resonance Imaging (MRI) or X-ray Computed Tomography (X-ray CT) is recommended.Item Open Access Physical validation of predictive acceleration control on a parallel hybrid electric vehicle(Colorado State University. Libraries, 2022) White, Samantha M., author; Bradley, Thomas, advisor; Quinn, Jason, committee member; Daily, Jeremy, committee member; Windom, Bret, committee memberPrevious research has been conducted towards the development of predictive control strategies for Hybrid Electric Vehicles (HEVs). These methods have been shown to be effective in reducing fuel consumption in simulation, but no physical validation has been conducted. This is likely due to the fundamental "curses" of dynamic programming mostly the "curse of dimensionality" wherein the run-time needed to generate the optimal solution renders the method unfit as a real-time control. Predictive Acceleration Event (PAE) control combats the run-time issues associated with dynamic programming based control methods by pre-computing the optimal solutions for common Acceleration Events (AEs). This method was physically implemented on a 2019 Toyota Tacoma that was converted into a Parallel-3 (P3) HEV with limited information on the vehicle, including a reduced access to the vehicle's Controller Area Network (CAN) bus. Results from on-track testing indicate a Fuel Economy (FE) improvement in the range of 7% is possible to achieve using PAE control in the real world. To the author's knowledge this is the first time that this type of testing has ever been implemented on a vehicle in the real world.Item Open Access Plate frame and bar plate evaporator model validation and volume minimization(Colorado State University. Libraries, 2019) Simon, John Robert, III, author; Bandhauer, Todd M., advisor; Quinn, Jason, committee member; Carter, Ellison, committee memberVapor compression chillers are the primary cooling technology for large building applications. Chillers have a large up front capital cost, with the heat exchangers accounting for the majority of the cost. Heat exchanger cost is a function of size, and therefore, a reduction in heat exchanger size can be correlated to a reduction in chiller capital cost. Few investigations focus on the reduction in heat exchanger size for vapor compression systems. Therefore, this investigation aims to decrease the size of chillers by predicting the minimum evaporator volume for a fixed performance. Only the evaporator was minimized because it was assumed that a similar process could be performed for the condenser in a future study. The study focused on a simple vapor compression cycle, and implemented high fidelity heat exchanger models for two compact heat exchanger types: brazed bar plate and gasketed plate and frame. These models accounted for variable fluid properties, phase change, and complex geometries within the evaporator core. The models used in this investigation were developed based on liquid-coupled evaporators in an experimental vapor compression system, and validated using collected data. The bar plate model was validated based on sizing and pressure drop to mean absolute errors of 14.2% and 14.0%, respectively. The plate frame model was validated for sizing to mean absolute errors equal to 7.9%; however, due to measurement uncertainty, pressure drop was not validated. The heat exchanger models were integrated into a simple vapor compression cycle model to determine the minimum required evaporator volume. Both heat exchanger types, in parallel and counter flow arrangements were minimized in this study. The minimum volume was achieved by varying the ratio between core length and number of channels. It was found that for both heat exchanger types, the parallel flow arrangement resulted in a smaller volume than the counter flow arrangement. Furthermore, the bar plate heat exchanger resulted in an optimum volume 91% smaller than the plate frame counterpart.Item Open Access Solid waste management: a comparative carbon footprint and cost analysis(Colorado State University. Libraries, 2018) Carroll, Andy, author; Sharvelle, Sybil, advisor; Bareither, Christopher A., advisor; Quinn, Jason, committee memberTo view the abstract, please see the full text of the document.Item Open Access Using prototypical sites to model methane emissions in Colorado’s Denver-Julesburg basin using mechanistic emissions estimation tool(Colorado State University. Libraries, 2023) Mollel, Winrose A., author; Olsen, Daniel B., advisor; Zimmerle, Dan, advisor; Baker, Dan, committee member; Quinn, Jason, committee memberThe BU methods estimate emissions by considering activity factors and emission factors averages for an extended period for a large area. Some TD methods use the ethane-methane ratio to attribute methane emissions from oil and gas facilities. The bottom-up (BU) inventory estimates are often used to drive the attribution of emissions indicated by TD data to different emission source categories. Despite widespread use, recent studies indicate that traditional bottom-up (BU) inventory methods do not adequately capture how variations in throughput and failure conditions impact gas composition and rate of emissions. Traditional BU methods typically do not model gas composition, although it differs among different facility configurations and impacts emissions from different equipment within one facility. Since most BU inventories utilize fixed emissions factors, emissions also do not scale due to throughput, which is particularly important for large emitters associated with failure conditions. Mechanistic emissions modeling can be used to address these shortcomings and make BU modeling more effective. This study illustrates how mechanistic modeling highlight changes in emissions due to variable throughput and equipment pressures and temperatures for the same production routed through the same or different production facility designs. The study uses the same mechanistic models to illustrate how the frequency of failure modes impacts both gas composition and total emissions. Results indicate mechanistic modeling could explain observed gas composition shifts in emitted emissions from production and midstream facilities over time, a key modeling input to improve voluntary and regulatory methane mitigation efforts.