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 20 of 28 for “"stall inception"”.
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Unsteady disturbance structures in axial flow compressor stall inception
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994.
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Simulation of spike stall inception in a radial vanted diffuser
… and stability. Experiments suggest that spike stall inception in centrifugal compressors can be formed by a vaned diffuser. To address these issues, a numerical study on an advanced, vaned-diffuser centrifugal compressor was conducted to investigate stall inception. A steady three-dimensional …
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Tip clearance flows in axial compressors: stall inception and stability enhancement
… 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 field and its role in the stall inception …
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Stall inception in high stage loading low pressure ratio transonic fans
… space that is highly challenging in terms of stall. Stall inception of a modern, high stage loading, low pressure ratio transonic was investigated using single-passage steady and full annulus unsteady computational fluid dynamics. The computational method was validated using experimental data …
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Blade passage flow structure effects on axial compressor rotating stall inception
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1996.
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Investigation of stall inception in centrifugal compressors using isolated diffuser simulations
… range of stable operating is limited by rotating stall and/or surge. Two distinct types of stall precursors can be observed prior to these phenomena: the development of long-wavelength modal waves or a short-wavelength, three-dimensional ow breakdown which is typically known as a "spike". The …
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A study of the rotating-stall inception in high-speed compressors
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994.
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Experimental investigation of rotating waves as a rotating stall inception indication in compressors
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1989.
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Two investigations of compressor stability : spike stall inception and transient heat transfer effects
… first is of the formation of spike-type rotating stall precursors. Recently, high fidelity computations have attributed pre-cursor formation to a leading-edge separation and consequent shedding of vorticity near the rotor tip due to high incidence. This hypothesis is assessed via experiments in a …
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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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Existence and Analysis of a Rotating Stall Inception Continuum & Development of Concept Questions in Fluid Dynamics
… presents two projects, an analysis of rotating stall inception for axial compressors in turbomachinery, and a description of the creation of Concept Questions for a text on internal flows. The first part of this thesis identifies flow behavior that defines two routes to rotating stall, known as …
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Development of a geometric model for the study of propagating stall inception based on flow visualization in a linear cascade
… cascade of compressor blades showed propagating stall at stagger angles of 36.5 and 45 degrees for angles of attack of 20 degrees and higher. At a stagger angle of 25 degrees, the development of a steady, separated boundary layer occurred with no propagation. The observed propagating stall …
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A computational model for rotating stall and inlet distortions in multistage compressors
… the non-linear aspects of short wavelength stall inception, part span stall cells, and compressor response to three-dimensional inlet distortions. The computed results demonstrated the first-of-a-kind capability for simulating short wavelength stall inception in multistage compressors. The …
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Computational Assessment of Axial Compressor Flowfield Instability
… unstable. Two examples of this are rotating stall (a compression system level instability) and so-called “Rotating Instabilities” (a localized fluctuation in the tip flow region). This thesis presents full-annulus URANS computations demonstrating newly discovered properties of spike-type …
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A methodology for centrifugal compressor stability prediction
… is limited by well-known phenomena, rotating stall and surge. Although the manifestation of the full scale instabilities is similar to the ones observed in axial machines, the stall inception in centrifugal compressors is less well understood. This thesis focuses on developing an integrated …
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A two-dimensional model to predict rotating stall in axial-flow compressors
… ongoing effort, a model to simulate rotating stall inception and development in axial-flow compressor stages was constructed. This model was applied to an isolated rotor build to investigate the sensitivity of the predicted stall behavior to the shape of the high-incidence portions of the …
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A Unified Framework for Characterization of Mode and Spike Routes to Rotating Stall
… we characterize modal and spike-type rotating stall inception for an isolated rotor using a low order, non-linear actuator disk model. The actuator disk representation is capable of capturing stall inception behavior given an axisymmetric total-to-static pressure rise characteristic. A …
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Tip-clearance effects in axial compressors
… the flow coefficient at which the compressor stalls and the mechanism by which stall inception occurs (spikes or modes). Furthermore, the industry ’rule of thumb’ that the stalling flow coefficient of an eccentric compressor is determined by the maximum tip-clearance is shown to be overly …
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The development and requirements of a body force database from two-dimensional and streamline curvature calculations
… from design conditions to flows below the stall point, for compressor stability analysis. The methodology is based on two-dimensional blade element calculations and a streamline curvature procedure to calculate the axisymmetric flow, although it can be extended to use three-dimensional …
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Axial compressor stability enhancement
… times. One source of instability is compressor stall. Stall problems can be reduced by machining cavities into the compressor casing adjacent to the rotor blades. This ‘casing treatment’ is the focus of the present work. Two treatment configurations are tested: circumferential grooves cut into …
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