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Articles 1 - 8 of 8
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Pylon Effects On A Scramjet Cavity Flameholder Flowfield, Andrew B. Freeborn
Pylon Effects On A Scramjet Cavity Flameholder Flowfield, Andrew B. Freeborn
Theses and Dissertations
Cavity flameholders in supersonic combustion ramjet (scramjet) combustors, while effective, fail to take advantage of the full combustor volume. Adding a pylon to the leading edge of a cavity flameholder generates a flowfield increasing mass exchange between the cavity and main combustor flow, increasing the mixing interface between flameholder products and main combustor flow, and exhibiting minimal Reynolds number effects. To demonstrate this modified flowfield driven by supersonic expansion behind the pylon, pylon-cavity flameholder flowfield data were obtained through a combination of wind tunnel experimentation and steady-state computational fluid dynamics (CFD). Flowfield effects of the pylon-cavity were examined at a …
Hypermixer Pylon Fuel Injection For Scramjet Combustors, Jason C. Doster
Hypermixer Pylon Fuel Injection For Scramjet Combustors, Jason C. Doster
Theses and Dissertations
Fueling the core airflow of a circular or elliptical scramjet combustor cross-section often requires intrusive geometries. Intrusive geometries can distribute the fuel evenly across the combustor cross-section and act as a flameholder for the fuel/air mixture. Compared to conventional transverse or angled wall injection, intrusive geometries allow easier penetration into the core combustor airflow and reduced fuel injection pressures. The design and testing of an intrusive pylon geometry for scramjet combustor fueling is the subject of this research. Three pylon configurations are compared: a basic pylon, a ramp pylon, and an alternating wedge pylon. All three pylon configurations exhibit the …
Hall Thruster Plume Diagnostics Utilizing Microwave Interferometry, Vipul Sharma
Hall Thruster Plume Diagnostics Utilizing Microwave Interferometry, Vipul Sharma
Theses and Dissertations
The fatigue behavior of two woven SiC-SiNC ceramic matrix composites (CMCs) was investigated at 1300 °C in laboratory air and in steam. The first composite (C1) consists of a PIP SiNC matrix reinforced with Sylramic (Syl) fibers woven in a five-harness satin weave fabric and coated with a proprietary dual-layer interface. The second composite (C2) consists of a modified PIP SiNC matrix reinforced with Sylramic-iBN (Syl-iBN) fibers woven in a five-harness satin weave fabric and coated with a proprietary dual-layer interface. The tensile stress-strain behavior was investigated and the tensile properties measured at 1300°C. Tension-tension fatigue behavior was studied for …
Laser-Induced Fluorescence And Performance Analysis Of The Ultra-Compact Combustor, Patrick J. Lakusta
Laser-Induced Fluorescence And Performance Analysis Of The Ultra-Compact Combustor, Patrick J. Lakusta
Theses and Dissertations
The AFIT Combustion Optimization and Analysis Laser (COAL) lab’s modular design and state-of-the-art diagnostic systems make it a flexible and important facility for the analysis of combustion processes. The objectives of the current research are to install several enhancements in the lab, validate the laser diagnostic system, characterize the igniter for AFIT’s Ultra-Compact Combustor (UCC) sections, and perform a non-intrusive laser diagnostic, performance, and high-speed video analysis of a flat-cavity UCC section. Validation of the laser system was accomplished using OH Planar Laser-Induced Fluorescence (PLIF) in a laminar hydrogen-air flame produced by a Hencken burner. Results are compared to previous …
Computational Design Of Upperstage Chamber, Aerospike, & Cooling Jacket For Dual-Expander Rocket Engine, David F. Martin Ii
Computational Design Of Upperstage Chamber, Aerospike, & Cooling Jacket For Dual-Expander Rocket Engine, David F. Martin Ii
Theses and Dissertations
To increase the performance of the current US satellite launch capability, new rocket designs must be undertaken. One concept that has been around since the 50s but yet to be utilized on a launch platform is the aerospike, or plug nozzle. The aerospike nozzle concept demonstrates globally better performance compared to a conventional bell nozzle, since the expansion of the jet is not bounded by a wall and therefore can adjust to the environment by changing the outer jet boundary. A dual-expander aerospike nozzle (DEAN) rocket concept would exceed the Integrated High Payoff Rocket Propulsion Technology initiative (IHPRPT) phase three …
Thermal Characterization Of A Hall Effect Thruster, Alex M. Bohnert
Thermal Characterization Of A Hall Effect Thruster, Alex M. Bohnert
Theses and Dissertations
The thermal characteristics of a Hall thruster directly influence thruster and spacecraft design. High temperatures affect the magnetic coil capabilities and cause higher insulator erosion rates, influencing both thruster performance and lifetime. The Hall thruster transfers heat through both radiation and conduction, and the spacecraft must handle this additional thermal energy. An infrared camera provides a non-intrusive method to analyze the thermal characteristics of an operational Hall thruster. This thesis contains the thermal analysis of a Busek Co. Inc. 200 W Hall thruster, using a FLIR ThermaCAM SC640 infrared camera. The Space Propulsion Analysis and System Simulator Laboratory at the …
Direct Initiation Through Detonation Branching In A Pulsed Detonation Engine, Alexander R. Hausman
Direct Initiation Through Detonation Branching In A Pulsed Detonation Engine, Alexander R. Hausman
Theses and Dissertations
Pulsed Detonation Engines are currently limited in operating frequency to the order of 40 Hz due to lengthy ignition and deflagration to detonation transition (DDT) times. An experimental study is conducted to determine the requirements necessary to eliminate these constraints through the concept of direct initiation. A branched detonation crossover setup is constructed and the operational requirements are determined. This research demonstrates the ability to directly initiate a detonation in a vacant tube from a detonation obtained through detonation branching. Using a hydrogen-air mixture, a tail-to-head detonation branching is achieved in which a detonation is seen to propagate from a …
Design Of An Oxygen Turbopump For A Dual Expander Cycle Rocket Engine, William S. Strain
Design Of An Oxygen Turbopump For A Dual Expander Cycle Rocket Engine, William S. Strain
Theses and Dissertations
The design of a pump intended for use with a dual expander cycle (LOX/H2) engine is presented. This arrangement offers a number of advantages over hydrogen expander cycles; among these are the elimination of gearboxes and inter-propellant purges and seals, an extended throttling range, and higher engine operating pressures and performance. The target engine has been designed to meet the needs of Phase III of the Integrated High Payoff Rocket Propulsion Technology (IHPRPT) program; thus, this pump must meet the program’s reliability, maintainability, and service life goals. In addition, this pump will be driven by warm gaseous oxygen. …