Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"Combustion Stability"”.
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The design of a combustion test facility for synthetic jet fuel research
… research areas, which pertained to ignition and combustion stability in gas turbines and the role played by various fuel attributes and properties. The project was conducted at the Sasol Advance Fuels Laboratory based at the University of Cape Town. The project entailed the design and …
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Diesel-cng dual fuel combustion characterization using vibro-acoustic analysis and response surface methodology
… terms of engine performance, exhaust emissions, combustion pattern and combustion stability. Within the investigation, a statistical method was proposed to analyse the vibro-acoustic signal generated by a knock sensor installed at the outer cylinder wall of the engine. The frequency distribution …
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Effects of charge motion control during cold start of SI engines
… enhanced charge motion on mixture preparation, combustion, and hydrocarbon (HC) emissions. Different charge motions were produced by three different shapes of charge motion control valves (CMCV), which block off 75% of the engine's intake ports. Cold-fluid steady state experiments were carried …
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The development and implementation of a hybrid rocket motor thrust stand to investigate the relationship between combustion chamber pressure and graphite rocket nozzle erosion in hybrid rocket motors
… to insulate the motor from the heat produced by combustion. Over time these inserts will erode due to oxidation at the surface wherein oxidizing species found in the combustion products react with the carbon to form carbon monoxide. It has been shown that the largest contributors/oxidants to …
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Swirl-stabilized lean-premixed flame combustion dynamics: An experimental investigation of flame stabilization, flame dynamics and combustion instability control strategies
Though modern low-emission combustion strategies have been successful in abating the emission of pollutants in aircraft engines and power generation gas turbines, combustion instability remains one of the foremost technical challenges in the development of next generation lean premixed combustor …
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Combustion optimization in a hydrogen-enhanced lean burn SI engine
… attractive performance incentives. Lowered combustion temperatures inhibit NO[sub]x pollutant formation while reduced manifold throttling minimizes pumping losses, leading to higher efficiency. These benefits are offset by the reduced combustion speed of lean mixtures, which can lead to high …
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Impact of retarded spark timing on engine combustion, hydrocarbon emissions, and fast catalyst light-off
… effects of substantial spark retard on engine combustion, hydrocarbon (HC) emissions, feed gas enthalpy, and catalyst light-off. Engine experiments were conducted at cold engine conditions for various ignition timings and air/ fuel ratios. Chemical and thermal energy of the exhaust gas was …
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Translation of dilution tolerance for gasoline SI engine
… a relationship between the various diluents and combustion related output parameters. One of these key outputs was determining the dilution tolerance for an engine. In order to achieve this goal, the fundamental of combustion were studied. The results from this study will be useful in developing …
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Effects of Fuel Split Ratio on NOₓ Emissions of a Lean-burn Staged Combustor
… the near future, aircraft-based lean-burn staged combustion becomes a promising solution in reducing NOₓ emissions. This thesis investigates the effects of a lean-burn staged combustor’s fuel split ratio and staging threshold on the NOₓ emissions for both a sea-level static scenario and a …
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Managing transient behaviors of a dual mode spark ignition-- controlled auto ignition engine with a variable valve timing system
… referred to as Controlled Auto Ignition (CAI) combustion in the literature. The objective of the study can be divided into two topics. First, the dynamic nature of load trajectory and several important phenomena in CAI mode were investigated. Second, the issues encountered during mode …
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Combustion characteristics of a spark ignition engine operating with liquid lpg injection
… to the usage of alternative fuels in internal combustion engines. Liquefied petroleum gas (LPG) is one of the most popular alternative fuels for spark ignition (SI) engines that received lots of attention due to its availability and acknowledged superior properties than gasoline. However, …
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Reducing emissions of a large bore two stroke cycle engine using a natural gas and hydrogen mixture
… formation is primarily a function of in-cylinder combustion temperatures. A challenge for engine researchers is to identify methods to lower combustion temperatures while maintaining complete combustion. Blending hydrogen into an engine's fuel can lower in-cylinder combustion temperatures and …
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An Investigation of Lean Premixed Hydrogen Combustion in a Gas Turbine Engine
… about the carbon emissions associated with the combustion of conventional hydrocarbon fuels, hydrogen is gaining more attention as a clean alternative. The combustion of hydrogen in air produces no carbon emissions. However, hydrogen-air combustion does have the potential to produce oxides of …
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Development of mesoscale burner arrays for next generation compact gas turbines
… burner array was designed to improve the overall combustion stability by exploiting flame-to-flame interactions under fuel-lean operation. Moreover, its design can be adjusted by scaling the element dimensions or array size to flexibly accommodate a wide range of combustion power outputs. The …
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Acoustic boundary condition estimation in a near-scale gas-turbine combustor
… admittance of the inlet and outlet ports of a combustion chamber is presented. Parameter estimation techniques of Gauss linearization and genetic algorithms are employed to recover the acoustic boundary conditions. These techniques are used with a combination of two resources: dynamic pressure …
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Controller Design for a Swirl Injection Hybrid Launch Vehicle
… new development of rocket engines which swirl combustion gases to gain combustion stability benefits, and in the case of hybrid rocket engines, fuel regression benefits as well. The stability of the launch vehicle dynamics due to the internal torque has not been discussed before. To the …
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Improving the Efficiency of Gas Engines using Pre-chamber Ignition
… of this project is to explore and understand the combustion phenomenon in engines operating on gaseous fuels, and develop technologies as an alternative to the present diesel engine technologies for heavy duty applications; which are facing severe challenges like stringent emissions norms, high …
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Lean-burn characteristics of a gasoline engine enriched with hydrogen from a plasmatron fuel reformer
… NOx emissions. Hydrogen addition reduces the combustion variability. In this engine concept supplemental hydrogen is generated on-board the vehicle by diverting a small fraction of the gasoline to a plasmatron where it is partially oxidized into a stream containing hydrogen, carbon monoxide, …
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Turbo Charged Low Temperature Combustion - Experiments, Modeling and Control
… technology involves the use of internal combustion engines in one way or another. Because of the large numbers of internal combustion engines in use around the world, their emissions have a significant environmental impact. Therefore, considerable efforts have been invested into …
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