Search

Your search keyword '"Sheard, A. G."' showing total 207 results
Start Over Author "Sheard, A. G."
207 results on '"Sheard, A. G."'

3. From Loose Groups to Effective Teams: The Nine Key Factors of the Team Landscape.

Author

Sheard, A. G. and Kakabadse, A. P.

Abstract

A loose group of individuals working on a task differs from an effective team on nine factors: clearly defined goals, priorities, roles and responsibilities, self-awareness, leadership, group dynamics, communications, content, and infrastructure. Ways to eliminate barriers and speed formation of effective teams could be based on those factors. (Contains 23 references.) (SK)

Published
2002

5. Experimental aeroacoustic studies on improved tip configurations for passive control of noise signatures in low-speed axial fans

Author

Bianchi, Stefano, Corsini, Alessandro, Rispoli, Franco, and Sheard, Anthony G.

Subjects
Noise control -- Methods, Fans -- Mechanical properties, Fans -- Acoustic properties, Science and technology
Abstract

This paper presents the findings of an investigation on the use of several blade-tip configurations (modified by the addition of various end plates at the blade tip) for passive noise control in industrial fans. Utilizing an experimental technique developed to investigate noise sources along the radius of the blades, together with cross-correlation and coherence analyses of the near field and far field, the modified blade-tip configurations are shown to reduce the rotor-only aeroacoustic signature of the fan as a direct consequence of changes induced in tip-leakage flow behavior. These changes in the nature of flow mechanisms in the region of the blade tip are correlated with the spanwise noise sources, and their role in the creation of overall acoustic emissions is thus clarified. The tip-leakage flow structures are analyzed to identify their contribution to overall noise and interaction with other noise sources. Coherence spectra are also analyzed to investigate the relevance of the noise sources. The cross-correlations reveal distinctive acoustic signatures that are described in detail The methodology has been demonstrated to be effective in identifying (i) the blade-tip configuration with the best acoustic performance, and (ii) other significant noise sources along the blade span. The modified tip configurations are shown to have a significant effect on the multiple vortex behavior of leakage flow, especially with respect to the near-wall fluid-flow paths on both blade surfaces. The reduction in fan acoustic emissions is assessed and correlated with the control of tip-leakage flows achieved by the modified blade tips. [DOI: 10.1115/1.4000462]

Published
2009

6. Aerodynamic and mechanical performance of a high-pressure turbine stage in a transient wind tunnel

Author

Sheard, A. G., Schultz, D. L., and Ainsworth, R. W.

Subjects
621.4352, Aerodynamics and heat transfer, Aero engines, Mechanical engineering, Turbomachinery hypersonics and aerodynamics, turbomachinery, aerodynamics, mechanical performance of a high pressure turbine stage, transient wind tunnel
Abstract

Unsteady three-dimensional flow phenomena have major effects on the aerodynamic performance of, and heat transfer to, gas-turbine blading. Investigation of the mechanisms associated with these phenomena requires an experimental facility that is capable of simulating a gas turbine, but at lower levels of temperature and pressure to allow conventional measurement techniques. This thesis reports on the design, development and commissioning of a new experimental facility that models these unsteady three-dimensional flow phenomena. The new facility, which consists of a 62%-size, high-pressure gas-turbine stage mounted in a transient wind tunnel, simulates the turbine design point of a full-stage turbine. The thesis describes the aerodynamic and mechanical design of the new facility, a rigorous stress analysis of the facility’s rotating system and the three-stage commissioning of the facility. The thesis concludes with an assessment of the turbine stage performance.

Published
1989

19. A Critical Review of Stall Control Techniques in Industrial Fans

Author

Bianchi, Stefano, Corsini, Alessandro, Sheard, Anthony G., and Tortora, Cecilia

Subjects
Article Subject
Abstract

This paper reviews modelling and interpretation advances of industrial fan stall phenomena, related stall detection methods, and control technologies. Competing theories have helped engineers refine fan stability and control technology. With the development of these theories, three major issues have emerged. In this paper, we first consider the interplay between aerodynamic perturbations and instability inception. An understanding of the key physical phenomena that occurs with stall inception is critical to alleviate stall by design or through active or passive control methods. We then review the use of passive and active control strategies to improve fan stability. Whilst historically compressor design engineers have used passive control techniques, recent technologies have prompted them to install high-response stall detection and control systems that provide industrial fan designers with new insight into how they may detect and control stall. Finally, the paper reviews the methods and prospects for early stall detection to complement control systems with a warning capability. Engineers may use an effective real-time stall warning system to extend a fan’s operating range by allowing it to operate safely at a reduced stall margin. This may also enable the fan to operate in service at a more efficient point on its characteristic.

Published
2013
Full Text
View/download PDF

20. A Critical Review of Computational Methods and Their Application in Industrial Fan Design

Author

Corsini, Alessandro, Delibra, Giovanni, and Sheard, Anthony G.

Subjects
Article Subject
Abstract

Members of the aerospace fan community have systematically developed computational methods over the last five decades. The complexity of the developed methods and the difficulty associated with their practical application ensured that, although commercial computational codes date back to the 1980s, they were not fully exploited by industrial fan designers until the beginning of the 2000s. The application of commercial codes proved to be problematic as, unlike aerospace fans, industrial fans include electrical motors and other components from which the flow will invariably separate. Consequently, industrial fan designers found the application of commercial codes challenging. The decade from 2000 to 2010 was focused on developing techniques that would facilitate converged solutions that predicted the fans’ performance characteristics over the stable part of their operating range with reasonable accuracy, using a practical computational effort. In this paper, we focus on elucidating aspects of the flow physics that one cannot easily study in a laboratory environment, discussing the challenges involved and the relative merits of the available modelling techniques. The paper ends with a discussion of the practical problems associated with the use of commercial codes in a development environment and finally the legislation that is driving the need for aerospace style computation methods.

Published
2013
Full Text
View/download PDF

37. A Meridional Fan

Author

Corsini, Alessandro, Rispoli, Franco, and Sheard, A. G.

Published
2008

Catalog

Books, media, physical & digital resources
See catalog results