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.
Results
Showing 1 to 14 of 14 for “"Laser ignition"”.
-
Laser ignition for internal combustion engines via fiber optic delivery
… the efficiency of Otto cycle engines, the ignition system is often a limiting factor. Many "high energy" ignition systems have been developed, but almost all of these are based on traditional electric arc spark plugs. Laser ignition represents a fundamentally different approach to igniting …
-
Development and testing of a solid core fiber optic delivery system and ultraviolet preionization for laser ignition
Laser ignition of natural gas engines has shown potential to improve many facets of engine performance including brake thermal efficiency, exhaust emissions, and durability as compared with traditional spark ignition. Laser ignition technology has yet to transition to industry primarily because no …
-
Investigation of the multi-physics of laser-induced ignition of transportation fuels
… to operate at conditions where successful spark ignition is difficult to achieve. Laser ignition is a proposed alternative ignition system capable of stable engine performance under these conditions. Fundamental studies are needed to fully characterize the complex, multi-physics nature of the …
-
Numerical Investigation of Laser-Induced Ignition Phenomena
<p>This thesis investigates various aspects of laser-ignition. Laser ignition is a form of combustion initiation by means of a focused laser pulse in a combustible mixture. The ignition process consists of a chain of processes with varying degrees of importance to the prediction of a successful …
-
Measurement of flame propagation through step changes in mixture composition
… blown at the center of a combustion bomb. A laser was used to ignite the mixture from the center. Flame speed was calculated from both a pressure trace analysis and from measuring the movement of the flame front through high speed Schlieren imaging. Both methods demonstrated good correlation …
-
Modifying burning rate and agglomeration size in aluminized composite solid propellants using mechanically activated metals
… has been applied to tailor aluminum particle ignition and combustion. In this research, mechanical activated aluminum magnesium powders are synthesized, tested in both laser ignition using CO2 and propellant. Prepared powders categorized into particle size that suitable for propellant …
-
Ignition and combustion behaviors of nano-composite energetic materials
… behavior of thermites. In this study, the ignition sensitivity of an aluminum molybdenum-trioxide (AI/M0O3) composite mixture was examined. Laser ignition experiments were performed to determine the ignition time and burn rates of newly developed nano-Al mixed with M0O3. The scope of this …
-
Autoignition and flame speed of premixed liquefied petroleum gas in a rapid compression machine: experimental results and reduced chemical kinetic mechanism
… and exhaust gas recirculation (EGR) on the autoignition and flame speeds of LPG/oxidizer/inert/EGR blends. Experiments were conducted with 100% propane and blends of propane with propene, ethane, isobutane, or n-butane. EGR was simulated with mixtures of Ar, CO2, CO, and NO at substitution …
-
Multifunctional reactive nanocomposite materials
… using 8Al-MoO_3 powders were ignited by a CO_2 laser. Ignition delays increased at lower laser powers and greater pellet densities. A simplified numerical model describing heating and thermal initiation of the reactive pellets predicted adequately the observed effects of both laser power and …
-
Reactive solids under shock compression
… materials, an apparatus to launch and monitor laser-driven flyer-plates was developed. This was coupled to a home built photonic Doppler velocimeter (PDV) which tracks the motion of flyer plates and embedded gauges. This system was characterized using PDV to determine the range of impact …
-
Machining-induced damage mechanisms in KDP crystals
… high-tech fields, including optical uniformity, laser frequency conversion, high-speed Q-switching, because KDP possesses excellent physical properties, such as superior photoelectric/piezoelectric capability, outstanding frequency-doubling effect and high nonlinear conversion efficiency. In …
-
Computational fluid dynamics modeling of a large bore two-stroke natural gas engine
… gas for fuel injection and use of alternative ignition systems such as pre-combustion chamber ignition and laser ignition are being considered as engine retrofit technologies. The characteristics of natural gas fuel jets emanating from a low pressure conventional poppet valve and from a …
-
Synthesis and characterization of metal-based reactive powders
… were investigated that could shorten aluminum ignition delays, increase combustion rates, and decrease the tendency of aluminum droplets to agglomerate. Here, Al-based reactive, mechanically milled materials are prepared and characterized. For powders with Fe, Ni, or Zn additives, the particles …