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 19 of 19 for “"flow coefficient"”.
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Assessment of a body force representation for compressor stability estimation
… derived from axisymmetric and three- dimensional flow fields, for use in the stability analysis of axial compressors. The body force database represents the body forces as a function of the local flow coefficient times the overall flow coefficient; doing this overcomes a source of non-uniqueness …
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Effects of blade damage on low pressure ratio fan windmill aerodynamics
… are used to resolve the rotor blade-to-blade flow field and investigate the effects of non-axisymmetric damage. RANS simulations have been performed to obtain details of the 3D flow features. The windmill condition is characterised by compressor work near the hub and turbine work near the …
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Characterization of cavitation instabilities in rocket engine turbopump inducers
… The investigation suggests the low flow coefficient design of the inducer drives the loss sensitivity and is the root cause behind the model's convergence issues. The results indicate the body force model is valid for the higher flow coefficient designs and lower stagger angles …
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A Unified Turbine Preliminary Design Study
… on lost correlations and do not include mixed flow architectures. On top of this many of the current charts contain little to no information about the various loss mechanisms, turbine characteristics and how both change through out the design parameter space. This thesis builds on the pre …
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Simulation of measuring bottom quark flow in heavy ion collisions using the CMS detector
… to characterize the measurement of bottom quark flow in relativistic Pb+Pb collisions using the Compact Muon Solenoid experiment. The Hydjet event generator is used to produce sample collision events at four centrality values between 0 and 12 fm. These events are processed using the simulation, …
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Role of tip clearance flow on axial compressor stability
… fluid dynamic phenomena that link tip clearance flow to the formation of short length-scale (spike) rotating stall disturbances has been carried out. It is found that the onset of growth in tip clearance blockage characterizes the lowest flow coefficient for which a steady blade passage solution …
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Tip-clearance effects in axial compressors
The flow in the tip-clearance gap of a compressor has a profound effect on its performance, but understanding of the actual flow phenomena involved is limited. The current work aims to improve the situation through a comprehensive set of tests on a compressor with different clearance sizes and …
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Probabilistic analysis of meanline compressor rotor performance
… performance variability of the rotor at design flow coefficient and near stall given typical variations in blade profile geometry, hub and casing diameters, and tip clearances. Monte Carlo simulation performed at both operating conditions shows that the coefficient of variation of pressure rise, …
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Variable pitch fan aerodynamics
… to describe the previously unresolved fan-stage flow field, and to investigate the influence of fan-stage design for a fixed forward design point. Computational studies are carried out on the Advanced Ducted Propulsor (ADP) variable pitch fan with a pressure ratio of 1.29. For changes in flow …
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Design of dense graded cold bituminous emulsion mixtures and evaluation of their engineering properties
… behaviour has been justified by the "complex flow" coefficient, a technique proposed by Traxler for bitumens. The viscosity of the emulsion is greatly influenced by the amount of binder and level of temperature. The hardness of binder does not change appreciably the viscosity value of the …
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A Unified Framework for Characterization of Mode and Spike Routes to Rotating Stall
… total-to-static pressure rise with respect to flow coefficient has been carried out to (i) define the links between the computed behavior of circumferentially propagating flow disturbances and those of established linearized analyses and (ii) describe both modes and spikes as different regimes …
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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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Flows through s-shaped annular, inter-turbine diffusers
… diffusers or swan neck ducts (SND's) provide flow continuity between the H.P. and L.P. turbine, which with diffusing of the flow allow; greater stage efficiencies to be achieved as a consequence of reducing both the stage loading and flow coefficient of the L.P. turbine. This thesis presents …
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Effects of Spanwise and Discrete Disturbances on Separating Boundary Layers on Low Pressure Turbine Blades
Flow measurements were made on two highly loaded, low pressure turbine blade configurations in a low-speed, linear cascade facility. The L1M blade has a design Zweifel coefficient of 1.34 with a peak cp near 47% cx (mid-loaded) and the Pack B blade has a design Zweifel coefficient of 1.15 with a …
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The effect of reaction on compressor performance
… and conventional levels of design work coefficient (Ψ=0.44) and flow coefficient (Φ=0.60) are set, the profile loss becomes independent of reaction. When the centrifugal effects are removed, 50% reaction is shown to minimise endwall loss, maximise stage efficiency and maximise operating …
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Flow Mechanisms and Transient Pressure Analysis Study For Multi-Stage Fractured Horizontal Wells In Shale Gas Reservoirs
… in the seepage model, especially in the linear flow model, is rarely given. Comprehensive consideration of adsorption, desorption and diffusion, using computer programming knowledge, such as shale gas reservoir fracturing horizontal well trilinear flow and five linear flow model, to research the …
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Flash gas bypass concept utilizing low pressure refrigerants
… separate refrigerant phases over wide ranges of flow conditions and the simple flow controlling device could be exploited in the flash gas bypass line. It would be convenient if the phase separation vessel could be implemented in the evaporator header. A methodic approach has been implemented …
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Axial compressor stall.
… to four stages, covering a wide range of design flow rates and also a change in design reaction. The purpose of the experimental work has been to gain a better understanding of the details of the flow in the stall cell, so as to make possible the prediction of the in-stall performance of axial …
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Unsteady Aerodynamics of Compact Axial Compressors
… to large-scale compressors due to a transitional flow field with large regions of separation. This thesis investigates how Reynolds number variations affect the three-dimensional and unsteady flow field in a compact axial compressor both pre-stall and in stall. An experimental study has been …