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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
301

Coriolis effects in bladed discs

Ruffini, Valentina January 2016 (has links)
New aero-engine architectures are currently being developed to satisfy the increasing demand for fuel-efficiency and lower noise, pushing the boundaries of todays design practice. These unproven designs require additional effort to ensure safety to high-cycle fatigue and flutter, widely acknowledged as a main risk for turbomachinery components. This calls for a new focus on phenomena that have been little investigated in the past due to their minor relevance for traditional designs, like the Coriolis effect. The Coriolis effect can cause an increase in the number of resonance frequencies, and generate global travelling-wave modes that can affect performance and flutter stability. Experimentally validated prediction and analysis methods are essential to ensure the accurate evaluation of the impact of the Coriolis effect on future engine designs. The major finite element (FE) software packages were systematically assessed, and proven to provide reliable simulations of the dynamics of bladed discs when the Coriolis effect is included. Experimental modal tools for the detection and identification of the Coriolis effect are also needed, to provide accurate interpretation of the data for model validation and updating. For this purpose, a dedicated rotating test rig was designed and manufactured. A novel Multiple Input Multiple Output testing framework was developed, based on the use of an array of strain gauges and piezoelectric actuators in combination with a poly-reference identification method, for the extraction of the full set of modal parameters arising in a bladed disc from the Coriolis force. The new technique allowed the successful recovery of Campbell diagrams, damping and strain mode shapes. Left displacement eigenvectors, which appear in the FRF formulation due to the Coriolis effect, could also be extracted and validated for the first time. An accurate comparison was conducted between the measurement data and the FE results, and confirmed the reliability of the new approach.
302

The prediction of three-dimensional gas fired combustion chamber flows

Megahed, I. E. A. January 1979 (has links)
No description available.
303

Mixed-convection heat transfer in vertical channels with arbitrary wall conditions

Sarmast, R. January 1979 (has links)
No description available.
304

Kerosene spray flames

Attya, A. E.-M. M. A. January 1983 (has links)
No description available.
305

Elastohydrodynamic film thickness of water-based hydraulic fluids

Wan, G. T. Y. January 1983 (has links)
No description available.
306

Structural and aeroelastic vibration analysis of bladed systems

Imregun, M. January 1984 (has links)
No description available.
307

Solutions of the heat-conduction equation with phase change and moving boundaries

Rejal, M. A. January 1984 (has links)
No description available.
308

Modelling in-plant aspects of nuclear reactor accidents

Zarimpas, N. January 1985 (has links)
No description available.
309

Predicition of air flow in diesel combustion chambers

Jahanbakhsh, Alireza January 1986 (has links)
No description available.
310

Tearing toughness and unstable ductile behaviour of a titanium alloy

John, S. J. January 1986 (has links)
No description available.

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