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.
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Showing 1 to 20 of 56 for “"Cold Flow"”.
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Cold Flow Performance of a Ramjet Engine
… of the ramjet were not achieved, and the final cold flow test with the nozzle installed was a failure due to improper configuration of the nozzle. The errors associated with this testing can largely be placed on the poor performance of the Cal Poly supersonic wind tunnel and the alterations made …
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Numerical modeling of cold flow and hot gas desulfurization in a circulating fluidized bed
… results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility.;Section II. …
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Development of a to-scale fluid mixing visualization process for analysis of cold-flow mixing
… visualize mixing in an annular mixer. A to-scale cold-mixing system was constructed from two cylinders, three pump systems, as well as an imaging system using a retrofitted green laser. The final model is a tested and proven system for flow imaging of two cold flows within a to-scale fuel-mixer.
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Visualization and velocity measurement of unsteady flow in a gas generator using cold-flow technique
Modeling of internal flow fields with hot, compressible fluids and sometimes combustion using cold flow techniques is discussed. The flow in a gas generator has been modeled using cold air. Experimental set up was designed and fabricated to simulate the unsteady flow with different configurations …
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Reduction Of Vortex-driven Oscillations In A Solid Rocket Motor Cold Flow Simulation Through Active Control
… was demonstrated via a scaled-down, cold-flow simulation that modeled closed-end acoustics. When vortex shedding frequencies couple with the natural acoustic modes of a choked chamber, potentially damaging low-frequency instabilities may arise. Although passive solutions can be …
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Experimental study on two-dimensional propagating edge flames: cold flow modeling and flame spread rate measurements
… mounted vertically such that air and fuel flow is upward while the flame spread is downward. Experiments were conducted with air velocity of 25 to 60 cm/s and fuel flows of 967 to 3036 ccm, resulting in centerline equivalence ratios between 0.5 and 2.0. Experiments results showed that the …
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Hydrodynamics and Mass Transfer in Bubble Columns
… the effect of column size and gas and liquid flow rates on column hydrodynamics and reactor performance. Among these approaches, phenomenological models based on either single-class or multi-class bubbles that were validated on cold flow systems have been successful in predicting the residence …
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Investigation of liquid fuel jet injection into a simulated subsonic "dump" combustor
… injection of liquid fuel into a two dimensional flowfield designed to represent a sudden-expansion "dump" combustor were performed under cold-flow conditions. Test conditions were as follows: 0.6 entrance Mach number, 25 PSIA total pressure, and nominally 75°F stagnation temperature. Two step …
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Development of a microreactor system for unsteady-state Fischer- Tropsch synthesis
… This reactor involves a supernatant gas flowing over a shallow fluidized bed of catalyst particles. Three systems were built: (1) a vibrofluidized-bed microreactor system for obtaining baseline carbon deposition infonnation under industrially important reaction conditions; (2) a …
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Simulation of Flow in a Solid Fuel Ramjet Cavity
Cold flow inside a Solid Fueled Ramjet (SFRJ) is simulated using large eddy simulations (LES). A finite element method using a Discontinuous Galerkin bases has been implemented in the open-sourced multi-physics software SU2. Novel LES formulations of the fuel-gas boundary conditions and the heat …
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Aerospike Thrust Vectoring Slot-Type Compound Nozzle
… of annular aerospike nozzles was conducted. Cold-flow blow-down testing along with solid modeling and rapid prototyping technology were used to investigate the effects of slot size, placement, geometry and orientation. The use of slot-type compound nozzles proved to be a feasible approach to …
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Fuel composition and quality sensing for diesel engines
… to a variety of contamination, degradation, and cold flow issues. In order to optimize engine performance and meet EPA emissions standards over a wide array of fuels, information about the fuel composition must be known in real time. Furthermore, protecting the engine from potential fuel …
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Gas- and solid-mixing behavior in a vibrated-bed microreactor with rapid switching of catalyst between gas atmospheres
A cold-flow vibated-bed microreactor system, operating at the room temperature and atmospheric pressure, was built and tested. The purpose of this microreactor was to simulate gas- and solid-mixing in a hot-flow microreactor system. The latter is being developed to study carbon deposition rates for …
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Modelling and diagnostic study of flow in an optical engine with negative valve overlapping for homogeneous charge compression ignition
… gas motion in an engine cylinder with different flow scales generates a varied range of shear stresses and deformations in the fluid, which leads to the gas turbulence. These flow irregularities combined with periodic engine operation induce gas fluctuations over time and cylinder volume. This …
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Heat transfer modeling of jet vane Thrust Vector Control (TVC) Systems
… in a two dimensional, sonic and subsonic, cold flow field, for both laminar and turbulent flow cases. Results consist of a numerical solution and a graphical representation of surface shear stress coefficient, Stanton number and convective heat transfer coefficient.
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An Integrated Aerodynamic-Ramp-Injector/ Plasma-Torch-Igniter for Supersonic Combustion Applications with Hydrocarbon Fuels
… to develop the device using the supersonic cold flow facilities at Virginia Tech. The experimental investigations included some of the following methods: shadowgraphs, surface oil flow, pressure-sensitive paint, high- or low-speed photography, aerothermodynamic sampling, and spectroscopy. …
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Bright Z ~ 3 Lyman Break Galaxies in Deep Wide Field Surveys
… found, which can be interpreted as arising from cold flow accretion. The relation also suggests that the cosmic star formation efficiency is about 5%-20% of the total cold flow mass. This cosmic star formation efficiency does not evolve with redshift (from z ~ 5 to z ~ 3), hosting dark matter …
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Experimental Investigation of a Lean, Premixed Gas Turbine Combustor Using Advanced Laser Diagnostics
… for each test condition, revealing a combustion flow field dominated by large-scale turbulent structures. Stabilization of the flame occurred primarily in the side recirculation zone at the edge of the premixer exit. Single-shot temperature measurements were made using coherent anti-Stokes Raman …
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An experimental simulation of liquid fuel injection into a heated subsonic gas crossflow
… this investigation, an approach to studying hot-flow subsonic cross-stream fuel injection problems with a less complex and less costly cold-flow facility was developed and implemented. An actual ramjet combustion chamber fuel injection problem was proposed where ambient temperature fuel was …
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Development and Ground Testing of Direct Measuring Skin Friction Gages for High Enthalpy Supersonic Flight Tests
… environment of the turbulent boundary layer in flows such as that in supersonic combustion ramjet (scramjet) engines, with a progression from free-jet ground tests to a design for an actual hypersonic scramjet-integrated flight vehicle. The designs were non-nulling, with a sensing head that was …
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