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 19 of 19 for “"ignition delay time"”.
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Measurement of ignition delay time of jet fuels in shock tube for the development of the chemical kinetic mechanism
… measurement of both overall and first-stage ignition delays for F-24 at 5–20 bar down to ~650–700 K and providing comparative data for a cycloalkane-rich CycloSAF. A Covariance Matrix Adaptation Evolution Strategy (CMA-ES) is then employed to optimize selected Arrhenius parameters of the 16 …
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Shock Ignition of N-Heptane With Supplemental Hydrogen
… n-heptane (surrogate for diesel fuel) and air on ignition delay time at prototypic post-compression diesel engine conditions. Ignition delay time data was measured using the reflected shock wave technique at a pressure of 20 bar (representative of part load engine conditions), for three fuel …
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Ignition Delay Times of Natural Gas/Hydrogen Blends at Elevated Pressures
… For reheat gas turbines, understanding of the ignition delay times of high-hydrogen natural gases is important for two reasons. First, if the ignition delay time is too short, autoignition can occur in the mixer before the primary combustor. Second, the flame in the secondary burner is …
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Ignition delay study of next generation alternative jet fuels in a rapid compression machine
… primary goal of this study is to determine the ignition delay time of jet fuels of interest; conventional, alternative, and surrogate blends. By measuring the pressure trace of autoignition in rapid compression machine, ignition delay time is captured through the pressure derivative. Category A …
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The role of fuel in determining the high load limit of controlled auto-ignition engines
Controlled Auto-Ignition (CAI) engines have the potential to increase fuel economy while lowering nitrogen oxide and soot emissions. One hurdle that is currently being faced is the engine's inability to operate at high loads due to a large Maximum Pressure Rise Rate (MPRR). To address this issue, …
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Autoignition study of next generation aviation fuels and components
… hydrocarbon components by investigating their ignition delay times at various autoignition conditions. Complex multistage ignition behavior of fuels at specific conditions are further evaluated with rapid compression machine (RCM) experimental results and CHEMKIN chemical mechanism simulations. …
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Simulation von Verbrennungsprozessen mit einem stochastischen Partikel-Modell
… is determined by rates – probabilities over time – for the respective processes chemical reaction, diffusion, and flow. The time evolution of the probability of the system state is described by a Master-Equation which can be simulated with the minimal-process-method – a Monte-Carlo method. …
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Autoignition in turbulent two-phase flows
… investigated, CMC could correctly capture the ignition, propagation and anchoring phases of the spray flame. Inclusion of droplet terms in the CMC equations had little influence on the numerical predictions, in line with the findings of other authors. The third part of the dissertation presents …
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Ignition by Nanosecond Repetitively Pulsed Discharges
… pulsed plasmas can have strong benefits on ignition, including a reduction of ignition delay times, a decrease of minimum ignition energies, or an extension of lean ignition limits. These effects are highly dependent on experimental conditions such as temperature, mixture, pulse repetition …
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Machine Learning-Driven Uncertainty Quantification and Parameter Analysis in Fire Risk Assessment for Nuclear Power Plants
… heat release rate per unit area of the cable, ignition source heat release rate, ventilation area, and cabinet volume in determining peak HRR. Sensitivity analysis revealed that HRRPUA is the most significant parameter. For spill fires, the models underscore the significance of substrate …
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Chemical kinetic modeling of oxy-fuel combustion of sour gas for enhanced oil recovery
… tends to improve flame stability through a lower ignition delay time. Water diluted oxy-fuel combustion leads to higher burning velocities at elevated pressures than CO 2 dilution or air combustion, which also facilitates flame stabilization. In a mixed CH4 and H2S flame, H25 is oxidized …
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Combustion Kinetics of Advanced Biofuels
… such as, the homogeneous charge compression ignition (HCCI) engine is warranted. This dissertation concentrates on the combustion kinetics of DIPK over a wide range of temperature and pressure with a focus on HCCI engine application. An existing DIPK kinetic mechanism has been reviewed and a …
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Shock Tube and Mid-IR Laser Absorption Study of Combustion Kinetics
… absorption systems are used to investigate the ignition and pyrolysis processes of target fuels. The research problem is motivated by concern about climate change and diminishing fossil fuels. There is a need to develop advanced combustion systems and use more alternative fuels. Innovative …
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Rural electrification from local resources : biomass pyrolysis oil combustion in a direct injection diesel engine
… that these fuels exhibit excessively long ignition delay, rendering them dependant on auxiliary ignition sources for diesel engine operation. This work focuses on examining what physical and chemical processes may explain poor pyrolysis oil ignition quality, and what can be done to improve …
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An Investigation Of The Autoignition Of Power Generation Gas Turbine Fuel Blends Using A Design Of Experiments Approach
… of the burner design. In particular, autoignition of the premixed fuel and air prior to entering the main burner is a potential concern when using exotic fuel blends. To obtain much-needed data in this area, autoignition experiments for a wide range of likely fuel blends containing CH4 …
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Spray and combustion characteristics of acetone-butanol-ethanol and diesel in a constant volume chamber and a diesel engine
… retarded combustion phasing, including longer ignition delay time, retarded CA50 timing, peak pressure timing, and end of combustion timing. Accelerated heat release during CA10~CA50 indicates a higher degree of premixed combustion. Overall soot emissions were lower and NOx emissions were …
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The role of microstructure on the combustion and impact behavior of mechanically activated nickel/aluminum reactive composites
… in order to increase combustion velocity and ignition sensitivity. Their combustion and mechanical impact behavior is being studied to develop the understanding needed so that the materials can be ultimately developed for applications such as multi-functional energetic materials, blast …
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Lean Premixed Prevaporised Combustion for Microturbines
… the three fuels differ significantly in their ignition delay times and extinction strain rates but are relatively similar in their laminar flame speeds and adiabatic flame temperatures. These results highlight the importance of fuel choice in microturbine combustion systems that rely on …
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Autoignition and combustion chemistry of kerosene type fuels and components
… stable engine operation, which are sensitive to ignition and combustion processes. Alternative fuels from various feedstocks are proposed as substitutes for conventional fuels. These alternative fuels can vary significantly in physical and/or chemical properties. In order to incorporate …