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Full-Text Articles in Engineering
Performance Measurements Of Direct Air Injection In A Cavity-Based Flameholder For A Supersonic Combustor, Scott G. Edens
Performance Measurements Of Direct Air Injection In A Cavity-Based Flameholder For A Supersonic Combustor, Scott G. Edens
Theses and Dissertations
For several years the Air Force Research Lab Propulsion Directorate has been studying the difficulties in fueling supersonic combustion ramjet engines with hydrocarbon based fuels. Recent investigations have focused on the use of direct air injection into a directly-fueled cavity-based flameholder. Direct air injection has been shown qualitatively to be a valuable tool for improving cavity combustion. Little quantitative data is available that characterizes the performance of cavity-based flameholders. The objective of this research was to quantitatively determine the specific advantages and disadvantages of the direct air injection scheme. This was accomplished via intrusive probing into a supersonic free stream …
Effects Of Pressure On Coal Pyrolysis At High Heating Rates And Char Combustion, Dong Zeng
Effects Of Pressure On Coal Pyrolysis At High Heating Rates And Char Combustion, Dong Zeng
Theses and Dissertations
Clean coal technologies are now becoming popular because of their high efficiencies and minimal environmental impact. Higher operating pressures have been applied to clean coal technologies. The effect of pressure on coal pyrolysis and char combustion has been extensively studied but still remains to be further explored. The objective of this project was to characterize high pressure, high heating rate coal pyrolysis and char combustion, with emphasis on improving 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. …
Effects Of Fuel Molecular Structure And Composition On Soot Formation In Direct-Injection Spray Flames, Kenth Ingemar Svensson
Effects Of Fuel Molecular Structure And Composition On Soot Formation In Direct-Injection Spray Flames, Kenth Ingemar Svensson
Theses and Dissertations
Numerous investigations have been conducted to determine the effect of fuel composition and molecular structure on particulate emissions using exhaust gas analysis, but relatively few measurements have been obtained in-cylinder or under conditions where fuel effects can be isolated from other variables. In this work, dimethoxymethane was used as the base fuel to produce a non-sooting flame in a constant volume combustion vessel at 1000 K, and a density of 16.6 kg/m3. A second fuel was then added incrementally to determine an incipient soot limit. Line-of-sight extinction measurements were used as the primary diagnostic tool to determine if a correlation …
Comprehensive Black Liquor Droplet Combustion Studies, Leong-Teng Ip
Comprehensive Black Liquor Droplet Combustion Studies, Leong-Teng Ip
Theses and Dissertations
Black liquor, a byproduct from pulp production, is burned in a recovery boiler to generate electricity and recover inorganic materials. Black-liquor-droplet combustion is fundamental to understanding and potentially improving recovery boiler performance. This investigation reports comprehensive experimental data collected for a suite of five liquors. All the data were collected with newly-designed laboratory equipment, several aspects of which are unique. Single droplets were suspended on a thermocouple and heated in a furnace. Simultaneous diameter (size and shape), internal and surface temperatures, surface emissivity, and mass were measured under various furnace temperatures and gas compositions. The images recorded by the cameras …