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 17 of 17 for “"scramjets"”.
-
Mitigating Engine Unstart in Scramjets with Porous Bleeders
<p>The effectiveness of porous bleeders in mitigating unstart phenomena and enhancing isolator effectiveness in a hypersonic scramjet was investigated. Through computational fluid dynamics simulations, the impact of porous bleeder design parameters such as pressure jump coefficient and bleeder size …
-
Development and Testing of an Integrated Liquid-Fuel-Injector/Plasma-Igniter for Scramjets
A newly designed liquid fuel (kerosene) aeroramp injector/plasma igniter was tested in cold flow using the Virginia Tech supersonic wind tunnel at Mach 2.4. The liquid fuel (kerosene) injector is flush wall mounted and consists of a 2 hole aeroramp array of impinging jets that are oriented in a …
-
Experimental Investigation of a Flush-Walled, Diamond-Shaped Fuel Injector for High Mach Number Scramjets
An experimental investigation of a flush-wall, diamond-shaped injector was conducted in the Virginia Tech supersonic wind tunnel. The diamond injector was elongated in the streamwise direction and is aimed downstream angled up at 60° from the wall. Test conditions involved sonic injection of helium …
-
Development of nanosecond-gated laser induced breakdown spectroscopy for fuel mole fraction measurements in supersonic combustion
… systems such as supersonic combusting ramjets or scramjets are of great interest due to the high flight velocities and increased specific impulse offered over solid or liquid fuel rockets. Scramjets operate on the same Brayton cycle as typical jet turbine engines; however, there is no rotating …
-
Variable Geometry Scramjet Combustor Cavity Multi-Dimensional Treatise for Performance Analysis
The abilities of Scramjets and Ramjets, in their respective operating ranges, are partially bridged by dual-mode Scramjets. The limitations of operation are due to making a static motor that is designed to function in both modes resulting in low and high speed restrictions. This study covers the …
-
Pyrolysis and Flamelet Model for Polymethyl Methacrylate in Solid Fuel Sc(ramjet) Combustors
Scramjets have been identified as a potential long-term replacement for rocket and ramjet propulsion systems due to their enhanced performance at high Mach numbers. The introduction of solid fuels in these scramjet systems allows for shaping of the solid fuel cavity by additive manufacturing and …
-
Computational analysis of plasma actuation for control of shock-laden flows in scramjet isolators
Scramjets offer transformative capabilities for hypersonic propulsion, but are limited by instabilities associated with shock wave-boundary layer interactions (SWBLIs). These interactions can diminish engine performance and cause unstart, an aerodynamic phenomenon that can have catastrophic …
-
Evaluation of a Strut-Plasma Torch Combination as a Supersonic Igniter-Flameholder
… 5, efficient methods of propulsion are needed. Scramjets may be a solution to this problem. Supersonic combustion is one of the main challenges involved in the operation of a Scramjet engine. In general, both an igniter and a flameholder are needed to achieve and maintain supersonic combustion. …
-
Optimal Engine Selection and Trajectory Optimization using Genetic Algorithms for Conceptual Design Optimization of Resuable Launch Vehicles
… and models of turbofans, turbojets, ramjets, scramjets and rockets. Steele-Flight explored the design space through the use of a Genetic Algorithm to find the optimal engine combination to maximize payload. The results output by Steele-Flight were verified by a study in which the designer …
-
A combined cycle approach to dual-mode scramjet design and analysis
… govern the theoretical performance of dual-mode scramjets are conducted. The accompanying discussion of the analytical process and findings, supplemented by experimental observations, seeks to address common uncertainties and misconceptions regarding the dominant fluid processes present in these …
-
One Dimensional Analysis Program for Scramjet and Ramjet Flowpaths
One-Dimensional modeling of dual mode scramjet and ramjet flowpaths is a useful tool for scramjet conceptual design and wind tunnel testing. In this thesis, modeling tools that enable detailed analysis of the flow physics within the combustor are developed as part of a new one-dimensional …
-
Experimental study of flow choking and inlet unstart in an axisymmetric model scramjet
Made available in DSpace on 2018-09-27T16:28:03Z (GMT). No. of bitstreams: 3 BACCARELLA-DISSERTATION-2018.pdf: 11707373 bytes, checksum: 856182803b3b4bbc32de9773806c5add (MD5) LICENSE.txt: 4215 bytes, checksum: 6aa9b4b4beb7f8c687f2f47db1477e87 (MD5) PROQUEST_LICENSE.txt: 4561 bytes, checksum: …
-
Skin Friction Sensor Design Methodology and Validation for High-Speed, High-Enthalpy Flow Applications
… as that found in atmospheric re-entry vehicles, scramjets, jet engines, material testing, and industrial processes. Fully understanding and optimizing these complex flows requires an understanding of aerodynamic properties at high enthalpies, which, in turn, requires numerical and analytical …
-
Laser absorption spectroscopy for investigation of hypersonic propulsion
Advancements in scramjet technology have arisen from recent interest in hypersonic propulsion. Progress in ground-testing capabilities has accelerated this technological advancement, providing repeatable and controllable experimentation at lower costs than flight tests. A primary challenge of …
-
Investigations of Injectors for Scramjet Engines
An experimental study of an aerodynamic ramp (aeroramp) injector was conducted at Virginia Tech. The aeroramp consisted of an array of two rows with two columns of flush-wall holes that induce vorticity and enhance mixing. For comparison, a single-hole circular injector with the same area angled …
-
Digital holography for exploring instabilities and breakup of liquid jets in supersonic crossflows
Direct injection studies of liquid jets in supersonic crossflows (JICFs) are critical for understanding combustion in scramjet engines. Exploring these fluid dynamic interactions is not only an important step towards characterizing fundamental liquid breakup properties but also key for improving …
-
Scramjet Operability Range Studies of an Integrated Aerodynamic-Ramp-Injector/Plasma-Torch Igniter with Hydrogen and Hydrocarbon Fuels
An integrated aerodynamic-ramp-injector/plasma-torch-igniter of original design was tested in a Mâ = 2, unvitiated, heated flow facility arranged as a diverging duct scramjet combustor. The facility operated at a total temperature of 1000 K and total pressure of 330 kPa. Hydrogen (H2), ethylene …