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 27 for “"flow distortion"”.
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CFD modelling of flow distortion using OpenFOAM
… a computational fluid dynamic (CFD) study of flow related to wind engineering. The open source CFD code OpenFOAM was applied to three cases (i) flow over an oil platform, (ii) flow over a complex terrain and (iii) flow over a met mast. In order to verify the results, experimental work was …
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Non-Intrusive Sensing and Feedback Control of Serpentine Inlet Flow Distortion
… to infer circumferential total pressure distortion intensity found in serpentine inlet airflow was established using wall-pressure fluctuation measurements. This sensing technique was experimentally developed for aircraft with serpentine inlets in a symmetric, level flight condition. The …
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Effect of Flow Distortion on Fuel Mixing and Combustion in an Upstream-Fueled Cavity Flameholder for a Supersonic Combustor
… of scramjet combustion employ as uniform a flowpath as possible. These studies are important to isolate the effects of a given combustor configuration. However, such studies tend to ignore the effects of a shock train created by the vehicle installation and that this shock train changes over …
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CFD analysis and redesign of centrifugal impeller flows for rocket pumps
… objective was to reduce the circumferential exit flow distortion of the baseline impeller. Later in the study, the objective became raising the head coefficient of the impeller. The study presented in this thesis was also undertaken to demonstrate current CFD capabilities for impeller design. A …
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Active Flow Control of a Boundary Layer Ingesting Serpentine Diffuser
… ingested boundary layer creates strong secondary flows that lead to severe flow distortion at the engine face, increasing the possibility of engine surge. This study investigated the use of enabling active flow control methods to reduce engine-face distortion. An ejector-pump based system of …
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Quantifying the effects of airflow distortion on anemometer wind speed measurements from merchant ships
… the bridge in a region where the effects of air flow distortion, created by the presence of the ship, may be large. Until now it was not known whether measurements from such anemometers would be biased high or low, and the possible magnitude of any such bias was not known. <br/><br/> …
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Reduced fan noise radiation from a supersonic inlet
… a new inlet door geometry designed to reduce flow distortion and noise radiation. The new door geometry uses door passages with increased circumferential span to improve the distribution of the flow entering through the doors. In addition, the new design employs sonic flow velocity at the …
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Effect of BLI-Type Inlet Distortion on Turbofan Engine Performance
… ingesting the low velocity boundary layer flow through a serpentine inlet into a turbofan engine adversely affects the performance of the engine. The available literature has only yielded studies of the effects of this specific type of inlet distortion on engine performance in the form of …
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A Numerical Evaluation of Hypersonic Inward-Turning Inlets at Off-Design Conditions
… Inlet performance was characterized by the mass flow averaged total pressure recovery, Mach number, flow distortion, and absolute static pressure amplification at the end of the inlet and at the isolator outflow. Based on the off-design cases, unstart boundaries were estimated. The sensitivity to …
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3-D flow calculations of a bifurcated 2D supersonic engine inlet at takeoff
An internal, 3-D, viscous numerical flow simulation was performed on the rectangular-to-circular transition, bifurcated, 2D high speed civil transport engine inlet at takeoff. The objective of the study was to obtain the causes of flow distortion at the inlet fan face. The inlet was modeled with …
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An Experimental and Analytical Investigation of Dynamic Flow Response of a Fan Rotor with Distorted Inlet Flow
… gain insight and ultimately predict the dynamic flow response of a fan rotor with inlet flow distortion. Rotor exit total pressure circumferential profiles were accurately predicted using frequency response functions derived from experimental rotor response data. Using these predicted profiles, …
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Numerical Modelling of Shock Wave Boundary Layer Interactions in Aero-engine Intakes at Incidence
… to provide uniformly distributed, steady air flow to the engine fan face under a variety of flow conditions. However, during situations of high incidence, high curvature of the intake lip can accelerate flow to supersonic speeds, terminating with a shock wave. This produces undesirable shock …
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Computational analysis of plasma actuation for control of shock-laden flows in scramjet isolators
… Quasi-DC (Q-DC) plasma actuators for active flow control in scramjet isolators. A computational framework was developed to model internal supersonic flows with plasma actuation. The Reynolds-averaged Navier-Stokes (RANS) equations coupled with Menter’s Shear Stress Transport (SST) turbulence …
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An Operational Value Stream Analysis for Developmental Excellence
… learning models better capture the relevant flow mechanics, improving the circumferential distortion estimations in nacelle aerodynamics by over 10% compared to traditional heuristics. Finally, a CFD-based actuator disk source modeling approach demonstrates a 60% reduction in steady-state …
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A market and engineering study of a 3-kilowatt class gas turbine generator
… is degraded by secondary nonidealities including flow leakage, heat leakage, and thermal flow distortion. Although these nonidealities are present to some degree in all gas turbines, their impacts are larger in small-scale engines.
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Three-dimensional rotating stall inception and effects of rotating tip clearance asymmetry in axial compressors
The effects of two types of flow nonuniformity on stall inception behavior were assessed with linearized stability analyses of two compressor flow models. Response to rotating tip clearance asymmetries induced by a whirling rotor shaft or rotor height variations were investigated with a …
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Effect of struts on aeroacoustics of axisymmetric supersonic inlets
… relocating the strut position was to reduce the flow distortion and radiated noise level. The experiment was conducted at various fan operating conditions in order to simulate aircraft approach. The inlet was tested statically without simulating the inflight speed effects. Steady state …
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Full Scale Experimental Transonic Fan Interaction with a Boundary Layer Ingesting Total Pressure Distortion
… that lead to the formation of non-uniform flow introduced to the engine through boundary layer ingesting (BLI) inlets, creating a different operational environment from which the engines were originally designed. The goal of this study was to explore the effects such non-uniform flow would …
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Normal Shock Wave-Boundary Layer Interactions in Transonic Intakes at Incidence
… of a transonic engine intake is dominated by the flow-field over the nacelle lower lip, around which the flow might accelerate to supersonic speeds. A shock wave might appear and impinge on the incoming boundary layer. Flow separation may result from this interaction, leading to severe flow …
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Inhomogeneous, Anisotropic Turbulence Ingestion Noise in Two Open Rotor Configurations
… configurations with different non-uniform inflows were studied: a rotor ingesting the wake of an upstream cylinder and a rotor ingesting a thick axially symmetric boundary layer from an upstream centerbody. In both cases, the undisturbed inflow was measured without the rotor present in order …
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