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 50 for “"Pressure recovery"”.
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Area-schedule based design of high pressure recovery radial diffusion systems
… two parameters is shown to enable high diffuser pressure recovery. The diffusion in the semi-vaneless-space, controlled chiefly by the vane suction side geometry, plays a key role in improving diffuser performance. Removing excess thickness from the suction side eliminates flow overspeed, …
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Unsteady separation point injection for pressure recovery improvement in high subsonic diffusers
Thesis (S.M. and E.A.A.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2002.
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A wind tunnel facility for the evaluation of a land-based gas turbine diffuser-collector
… was evaluated through the use of wall static pressure measurements, a variety of probe traverse measurements, and Stereo-PIV. Flow within the collector and diffuser were determined to be heavily dependent upon the collector geometry. PIV measurements showed the development of two large counter …
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Propulsion system analysis for conceptual design: drag and losses of nozzles and mixed compression inlets
… have been created to predict drag and total pressure recovery for both axisymmetric and 2-D mixed compression inlet configurations. These inlets are designed for use in aircraft with sustained supersonic cruise capabilities such as the HSCT. The drag and pressure recovery prediction methods …
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Flow analysis and control in a subsonic inlet
… good performance in terms of distortion and pressure recovery at the AIP, the situation can degrade drastically when the inlet is put in off-design conditions, with the risk of compressor instabilities. Flow control is considered as a promising way to maintain inlet efficiency in off-design …
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Experimental evaluation of a propulsive wing concept
… number of 0.7 for extended runs of laminar flow, pressure thrust, and wake filling. A lowspeed wind tunnel test was performed using a model of the designed propulsive airfoil section in order to validate the tools which were used for design, as well as to verify the pressure thrust concept. …
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Active and hybrid flow control in S-ducts and diffusers
… multiple diagnostics, including wall-static pressure measurements, surface oil flow visualization and two-dimensional particle image velocimetry (PIV) measurements. Two variants of the PEDA - one with membrane-deployable VGs, another with always-deployed VGs - were designed and studied (at a …
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Synergistic diffuser/heat-exchanger design
… of such design concepts are conducted, providing pressure-recovery, viscous losses and thermal energy extraction sensitivities to cooling and annular blade geometry variations. Results show promising diffusion and heat-transfer capabilities that match or surpass current design performance. …
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The role of impeller outflow conditions on the performance and stability of airfoil vaned radial diffusers
… Stokes computations. The test article is a pressure ratio 5 tur-bocharger compressor with an airfoil vaned diffuser. The swirling flow rig is able to generate rotor outflow conditions representative of the compressor except for the periodic pitchwise unsteadiness, and ts a 0.86 scale …
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Performance optimization of a subsonic Diffuser-Collector subsystem using interchangeable geometries
… hardware was found to increase the subsystem pressure recovery by over 10% from baseline resulting in an approximate 1% increase in gas turbine power output.
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High lift configuration of a slotted natural laminar flow airfoil
… allows the typical rapid trailing-edge pressure recovery associated with NLF airfoils to be greatly reduced on the fore element, allowing for laminar flow across the entire airfoil upper surface. The slot provides a favorable injection of momentum to the flow over the aft-element upper …
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Hydrodynamics and heat transfer in shallow fluidized beds
… heat transfer rate and require very low bed pressure. However, in comparison with research on deep fluidized beds, only relatively few studies have been devoted to heat transfer in shallow beds, and results from the available literature are often inconsistent. This study represents an …
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Methodology Development and Investigation of Turbofan Engine Response to Simultaneous Inlet Total Pressure and Swirl Distortion
… simultaneously reproduces combined inlet total pressure and swirl distortion elements in a tailored profile intended to match a defined turbofan engine inlet distortion profile. The device design methodology was intended to be sufficiently generic to be utilized in support of any arbitrary inlet …
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Effectiveness of a Serpentine Inlet Duct Flow Control Scheme at Design and Off-Design Simulated Flight Conditions
… several simulated flight conditions. The total pressure distortion at the aerodynamic interface plane (AIP) was then used to predict the resulting stability for a compression system. This study was conducted using a model of a compact, low observable, engine inlet duct developed by Lockheed …
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Anger Expression, Harassment, and Evaluation: Cardiovascular Reactivity and Recovery to Mental Stress
… the source of provocation may moderate the recovery process. The current study adopts a multivariate approach to assess the interactive effects of dispositional anger in predicting the CVR and recovery to mental arithmetic (MA) stress with and without harassment in 47 male undergraduate …
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Characterization of performance-limiting flow mechanisms in a centrifugal compressor stage
… operating conditions to the observed compressor pressure rise, efficiency, and operability characteristics. Despite large differences in their geometry, the two diffuser configurations exhibit similar pressure recovery characteristics due to differences in exit nonuniformity and flow angle which …
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Iced Airfoil Separation Bubble Measurements by Particle Image Velocimetry
… ice simulation and therefore enhanced pressure recovery and reduced mean separation bubble length, each relative to the flowfield of a representative two-dimensional ice simulation. These effects appeared to result from the quasi-steady distribution of discrete, streamwise vortices …
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A Numerical Evaluation of Hypersonic Inward-Turning Inlets at Off-Design Conditions
… 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 equilibrium …
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3-D flow calculations of a bifurcated 2D supersonic engine inlet at takeoff
… inlet throughout the entire flowfield. A high pressure recovery was observed at the fan face. Radial distortion at the fan face was caused by thin boundary layers on the nose cone and cowl surfaces. Circumferential distortion was caused by pressure gradients produced by the wake of the splitter …
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Boundary-layer control of bluff bodies with application to drag reduction of tractor-trailer truck configurations
… using judiciously located fences to interrupt pressure recovery. Wind tunnel tests with a two-dimensional wedge airfoil model suggest that injection of momentum can significantly delay separation of the boundary-layer resulting in a narrow wake and the associated reduction in the pressure drag. …
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