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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 19 of 19 for “"Tip Leakage Vortex"”.
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Reynolds stress measurements in a turbine tip leakage vortex
… study of the structure of turbulence in a tip leakage vortex was conducted in a large scale, linear turbine cascade. The study was performed in a cross sectional plane 0.96 of the axial chord length downstream of the blade leading edge. The cascade consisted of five blades with an aspect …
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Formation and Development of the Tip Leakage Vortex in a Simulated Axial Compressor with Unsteady Inflow
The interaction between rotor blade tip leakage vortex and inflow disturbances, such as encountered in shrouded marine propulsors, was simulated in the Virginia Tech Linear Cascade Wind Tunnel equipped with a moving endwall system. Upstream of the blade row, idealized periodic inflow unsteadiness …
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Near Wall Behavior of Vortical Flow around the Tip of an Axial Pump Rotor Blade
… study of three-dimensional turbulent tip gap flow in a linear cascade wind tunnel with 3.3% chord tip clearance with and without moving endwall simulation. Experimental measurements have been completed in Virginia Tech low speed linear cascade wind tunnel. A 24" access laser-Doppler …
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The Effects of Free Stream Turbulence on the Flow Field through a Compressor Cascade
The flow through a compressor cascade with tip leakage has been studied experimentally. The cascade of GE rotor B section blades had an inlet angle of 65.1º, a stagger angle of 56.9º, and a solidity of 1.08. The final turning angle of the cascade was 11.8º. This compressor configuration was …
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Flowfield Downstream of a Compressor Cascade with Tip Leakage
… blade, 7 passage linear compressor cascade with tip leakage was built. The flowfield downstream of the cascade was measured using four sensor hot-wire anemometers, from which the mean velocity field , the turbulence stress field and velocity spectra were obtained. Oil flow visualizations were …
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Measurements of the Tip-gap Turbulent Flow Structure in a Low-speed Compressor Cascade
… presents results from a thorough study of the tip-gap turbulent flow structure in a low-speed linear compressor cascade wind tunnel at Virginia Tech that includes a moving belt system to simulate the relative motion between the tip and the casing. The endwall pressure measurements and the …
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An Experimental Investigation of Unsteady Surface Pressure on Single and Multiple Airfoils
… between the blades inviscid response and tip leakage vortex strength. Measurements of fluctuating surface pressure were made on a NACA 0015 airfoil immersed in grid generated turbulence. The airfoil model has a 2' chord and spans the 6' Virginia Tech Stability Wind Tunnel test section. Two …
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Reynolds-Averaged Navier-Stokes Computation of Tip Clearance Flow in a Compressor Cascade Using an Unstructured Grid
… code has been also developed and applied to the tip clearance flow in a highly staggered cascade. Surface grids are first generated in the flow passage and blade tip by using several triangulation methods including Delaunay triangulation, advancing front method and advancing layer method. Then …
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Unsteady Turbulence Interaction in a Tip Leakage Flow Downstream of a Simulated Axial Compressor Rotor
The unsteady behavior of a tip leakage flow downstream of a simulated axial compressor rotor has been studied. The Virginia Tech low speed linear cascade wind tunnel was adapted to model the unsteady tip leakage flow produced by a rotor operating in the vortical wakes of a set of stator vanes. The …
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Axial compressor stability enhancement
… at different axial locations over the blade tips. For the first time, it is shown that there are two locations where compressor stability is maximised; near the leading edge and near mid-chord. The interaction between the groove and the compressor flow field is then studied. It is found that …
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Some Features of Tip Gap Flow Fields of a Linear Compressor Cascade
… study of three-dimensional turbulent tip gap flows in the linear cascade wind tunnel, for two different tip gap clearances (t/c=1.65% and 3.3%). The experiments focus on near-wall flow field measurements for the stationary wall and moving wall, and static pressure measurement on the …
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Turbine tip clearance loss mechanisms
… the actual turbine environment, on turbine blade tip loss. The calculations were carried out for a subsonic high pressure turbine stage. The loss mechanism examined is that due to tip clearance vortex mixing. The effects examined were three-dimensional blade stacking, downstream transition duct …
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Hydrodynamic Design of Highly Loaded Torque-neutral Ducted Propulsor for Autonomous Underwater Vehicles
… of ducted propellers such as forces and moments, tip leakage vortex, leading-edge flow separation, and counter-rotating vortices formed at the duct trailing edge. The effect of variation of thickness for stator blades and different approaches for modeling the postswirl stator is presented. The …
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Measurements of Cooling Effectiveness Along the Tip of a Turbine Blade
… and pressure side injection on a turbine blade tip. Holes on the tip called dirt purge holes expel dirt from the blade, so other holes are not clogged. Wind tunnel tests are used to observe how effectively dirt purge and microcircuit designs cool the tip. Tip gap size and blowing ratio are …
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Large Tip Clearance Flows in High Pressure Stages of Axial Compressors
This thesis investigates over tip leakage where the tip clearance is large. In the high pressure stages of axial compressors the tip clearance can be typically 6% of span and the total blockage due to tip clearance can consume in excess of forty percent of the annulus height. Experimental and …
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Unsteady flows in cantilever compressor stator tip clearances and the effect of real tip geometry
… and turbulent flow structure within compressor tip flows. The simulations were performed with clearances of 1.6 and 3.2 percent of chord. The results show that the flow both within the gap and at the exit on the suction side are highly unsteady phenomena controlled by fine-scale turbulent …
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Effects of rotor tip blade loading variation on compressor stage performance
… generation associated with altering the rotor tip loading of an embedded compressor stage is assessed. Steady and unsteady three-dimensional computations, complemented by control volume analyses, for varying rotor tip loading distributions provided results for determining if aft-loading rotor …
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Tip clearance flows in axial compressors: stall inception and stability enhancement
The flow in the rotor tip clearance gap in an axial compressor influences the loss levels and the stall onset point. The role of tip clearance flows in the stall inception process is still debated, though. The aim of this thesis is to improve the fundamental understanding of the tip clearance flow …
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Comparative Analysis of Serrated Trailing Edge Designs on Idealized Aircraft Engine Fan Blades for Noise Reduction
… GE-Rotor-B blades and 7-passages with adjustable tip gap settings. It had an inlet angle of 65.1º, stagger angle of 56.9º and a turning angle of 11.8º. The tunnel was operated with a tip gap setting of 1.65% chord, with a Reynolds number based on the chord of 390,000. Blade loading measurements …