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 20 of 27 for “"Flat Flame"”.
-
Electrical impedance of methane flat flame
… if electrical impedance measurements of the flame are a direct indication of fuel/air ratio. Previous worked measured electrical resistance of the combustion of gases in an atmospheric combustor. From this work, it was conjectured that the complex impedance might provide more information …
-
Optical measurements of nano-aluminum combustion in a heterogeneous shock tube and in a flat flame burner
… in the hot ambient gases of a one dimensional flat flame burner. Three different particle sized were studied (50, 80, and 110 nm). The burntimes of each were measured using high speed CMOS imaging allowing for a comparison of burntimes in various types of environments. The results found OH …
-
The blow-off of burner flames
… is regarded as the primary variable controlling flame stability, and correlations have therefore been sought between burning velocity and blow-off flow rate. For this purpose, burning velocities have been determined by the cooled flat flame method, and blow-off flow rates have been measured for …
-
Effects of Pressure on Coal Pyrolysis at High Heating Rates and Char Combustion
… coal/char high pressure combustion models. A flat-flame burner was used in a high pressure laminar flow facility to conduct high temperature, high heating rate pyrolysis and combustion experiments for four coals. The high-heating-rate (10000 K/s), high-temperature atmosphere can better …
-
A Computational Fluid Dynamics Investigation of Thermoacoustic Instabilities in Premixed Laminar and Turbulent Combustion Systems
… reduced order models for the dynamics of laminar flat flames and swirl stabilized turbulent flames. A finite-volume based approach is being used to simulate reacting flows in both laminar and turbulent combustors. The study has been divided into three parts -- the first part involves the modeling …
-
Novel diode laser absorption techniques for combustion diagnostics
… profiles in reacting environments, such as flames. The generally non-intrusive nature and spatial resolution of these techniques are now preferred over on extractive sampling, followed by analysis using techniques such as gas chromatography. In this thesis two laser absorption measurement …
-
Effects of Moisture on Combustion of Live Wildland Forest Fuels
… differences, an experiment was designed to use a flat-flame burner to simulate a moving fire front which heated and ignited a stationary, individual fuel sample. Samples included various U.S. species from the California chaparral, the intermountain west, and the southeastern regions. Temperature, …
-
Formation mechanisms of combustion chamber deposits
… octane requirement increase, and changes in flame speed and thermal efficiency. A framework is developed for examining the physical and chemical processes that contribute to the formation of combustion chamber deposits. First, a hypothesis for the general mechanism of deposit formation is …
-
An investigation into the origin, measurement and application of chemiluminescent light emissions from premixed flames
… is a semi-empirical model for a Bunsen type flame. The second is a 1-D model for a ceramic honeycomb flat-flame burner using the full chemical kinetics description of the conversion from fuel to products along with a detailed energy equation, accounting for the radiation energy exchange …
-
Development of Color Ratio Thin Filament Pyrometry Approach for Applications in High Speed Flames
… pyrometry is a proven technique used to measure flame temperature by capturing the spectral radiance produced by the immersion of silicon carbide filaments in a hot gas environment. In this study a commercially available CMOS color camera was used, and the spectral response of each color channel …
-
A Method for Measuring Spatially Varying Equivalence Ratios with Application to Thermoacoustics
Computed tomography for flame chemiluminescence emissions allows for 3D spatially resolved flame measurements to be acquired using a series of discrete viewing angle camera images. To determine fuel/air ratios, the ratio of excited radical species (OH*/CH*) emissions using chemiluminescence can be …
-
Methodology For Validating Multi-Dimensional Engine Combustion Models And Fuel Surrogates Using An Optically Accessible Compression Ignition Engine
… of the natural soot luminosity on a McKenna Flat Flame Burner. Spectral and Coherent anti-Stokes Raman Spectroscopy (CARS) measurements are used to propose a value of α in the soot emissivity model.</p>
-
An Optical Analysis of the Blowoff Behavior for Bluff Body-Stabilized Flames in Vitiated Flow
<p>In bluff body-stabilized flames, a variety of physical phenomena contribute to the flame destabilization as lean blowoff is approached. These effects include increased strain on the flame shear layers, decreased attenuation of Bénard-von Kármán vortex shedding, and the presence of thermoacoustic …
-
Experimental and computational study of soot formation under diesel engine conditions
… in typical laboratory scale experiments, such as flat-flame burners, and since diesel engine data are difficult to interpret because of uncertainty in the local charge composition and thermal state, a new rapid compression machine (RCM) was built to study the phenomenon. The RCM provides a …
-
Determination of Flame Dynamics for Unsteady Combustion Systems using Tunable Diode Laser Absorption Spectroscopy
… emissions. Unfortunately, operating the flame at lean conditions increases susceptibility to thermoacoustic (TA) instability. Self-excited TA instabilities are a result of the coupling of the unsteady heat release rate of the flame with the acoustics of the combustion chamber. The result …
-
Effects of Moisture on Combustion Characteristics of Live California Chaparral and Utah Foliage
… as they were exposed to hot gases from a flat flame burner. The broadleaf species from both California and Utah had noticeable surface changes during the ignition process. All fresh samples showed a color change on the leaf surface from a light dusty color to a dark wet color. This is …
-
Investigation of stagnation-flow diamond-forming flames using advanced laser diagnostics
… stagnation-flow diamond-forming flames. In these flames, a rich acetylene/oxygen/hydrogen mixture accelerates through a nozzle and impinges on a water-cooled molybdenum substrate, stabilizing a flat-flame approximately 1 mm below the substrate. A thin, polycrystalline diamond film …
-
Laser induced incandescence imaging for the investigation of soot formation in laminar flames
… of soot concentration within a variety of novel flame sources and setups. Laser induced incandescence (LII) is an optical technique used in laser diagnostics to measure soot volume fraction and estimate particle size in-situ. Using imaging to measure LII allows for a range of combustion …
-
Implementation of Adaptive Filter Algorithms for the Suppression of Thermoacoustic Instabilities
… a first order low pass filter to simulate the flame dynamics of an unstable tube combustor. The second was a flat flame, methane-air Rijke tube. The third can be considered a quasi-LDI liquid fuel combustor with a thermal output of approximately 30 kW. Actuation included the use of an acoustic …
-
Analysis of nitrogen oxide emissions produced during combustion of cracked-ammonia fuels
… in terms of combustion. This work compares the flame stability and NOx production of the two mixtures (with and without additional nitrogen). The range of operating conditions (equivalence ratio, fuel-hydrogen mole fraction, axial velocity) at which laminar burner-stabilized flames exist is …
Page 1 of 2