Filters
Availability
Publication Year
Resource Type
Faculty
School/Institute
Publication Search Results
Sort
Results per page
1 - 10 of 168
-
-
-
-
-
(2009)Conference PaperThe non-intrusive measurement of the condition of blades within a gas turbine would be a significant aid in the maintenance and continued operation of these engines. Online condition monitoring of the blade health by non-contact measurement methods is the ambition of most techniques. The current dominant method uses proximity probes to measure blade arrival time for subsequent monitoring. It has recently been proposed however, that measurement of the turbine casing vibration response could provide a means of blade condition monitoring, and even give the prospect of providing an estimation of the blade modal parameters. The casing vibration is believed to be excited pre-dominantly by (i) the moving pressure waveform around each blade throughout its motion and (ii) the moments applied by the stationary stator blades. Any changes to the pressure profile around the rotating blades, due to their vibration, will in turn affect these two dominant excitation forces, such that there will be some correlation between the casing response and blade vibrations. Previous work has introduced an analytical model of a gas turbine casing, and simulated pressure signal, associated with the rotating blades. The effect of individual rotor blade vibrations has been developed in order to understand the complex relationship between these excitation forces. A simplified turbine test rig has been constructed. Various aspects of the previous analytical modelling are presented, and then investigated and verified using results from the experimental program with this simplified test rig.
-
-
(2009)Conference PaperThe non-intrusive measurement of blade condition within a gas turbine would be a significant aid in the maintenance and continued operation of these engines. Online condition monitoring of the blade health by non-contact measurement methods is obviously the ambition of most techniques, with a number of methods proposed, investigated and employed for such measurement. The current dominant method uses proximity probes to measure blade arrival time for subsequent processing. It has been recently proposed however, that measurement of the turbine casing vibration response could provide a means of blade condition monitoring. The casing vibration is believed to be excited pre-dominantly by (i) the moving pressure waveform around each blade throughout its motion and (ii) the moments applied by the stationary stator blades. Any changes to the pressure profile around the rotating blades, due to their vibration, will therefore in turn affect these excitation forces. Previous work has introduced an analytical model of a gas turbine casing, and simulated pressure signal associated with the rotating blades. The model has been extended in this paper to more closely represent a commercial gas turbine with experimental verification being presented for various aspects of the analytical modelling procedure.
-
(2009)Journal ArticleThere are hopes that new learning technologies will help to transform university learning and teaching into a more engaging experience for 21st century students. But since 2000 the changes in campus university teaching have been more limited than expected. I have drawn on ideas from organizational change management research to investigate why this is happening in one particular campus university context. My study examines the strategies of individual lecturers for adopting e-learning within their disciplinary, departmental and university work environments; to develop a conceptual framework for analysing university learning and teaching as a complex adaptive system. This conceptual framework links the processes through which university teaching changes, the resulting forms of learning activity and the learning technologies used - all within the organizational context of the university. The framework suggests that systemic transformation of a university's learning and teaching requires coordinated change across activities that have traditionally been managed separately in campus universities. Without such coordination, established ways of organising learning and teaching will reassert themselves, as support staff and lecturers seek to optimise their own work locally. The conceptual framework could inform strategies for realising the full benefits of new learning technologies in other campus universities.
-
(2009)Conference PaperThe effect of introducing combinations of spherical dimples and protrusions in a shallow rectangular channel on the flow and heat transfer in the laminar regime has been studied numerically. Four different cases were investigated. These consisted of: an isolated dimple, an isolated protrusion both placed on the centerline of one of the wide face of the channel, a combination of a dimple located on the centerline of the wide face of the channel and a protrusion located downstream but shifted to the side, and finally, a combination in which the protrusion and the dimple are reversed. The resultant, very complex flow structure and thermal fields in the channel are presented. The introduction of a single dimple results in a small enhancement of heat transfer and a very small reduction in pressure drop relative to those obtained in a smooth channel. However, a significant enhancement in heat transfer obtained from a single protrusion is associated with marginal increase in pressure drop. The addition of a protrusion downstream of the dimple leads to an increase of 30% in heat transfer augmentation above that which pertains for the isolated protrusion without any increase in the pressure drop. With the reversal of the positions of the protrusion and the dimple no effect on either the pressure drop or the heat transfer has been observed.
-
(2009)Conference PaperAustralia leads the world in some areas of photovoltaic technology development, yet current innovation system limitations have seen local innovation overtaken by more rapid international development, or local product development moving offshore for commercialisation. Innovation is traditionally viewed as a linear progression through phases of early research, demonstration, commercialisation and market uptake, and this traditional view strongly emphasises the importance of the early phases. The latest thinking on innovation suggests that technological learning occurs not only through R&D, but also through manufacturing and marketing activities and through the interactions of actors within networks. In this paradigm, technology diffusion, as well as invention and adoption, plays a role in determining the direction of technological change. Organisational change and institutional change, which are critical in determining which technologies become established, are considered to be as important as technical change. This paper proposes the use of an innovation systems framework to assess the characteristics of the Australian PV innovation system, such as the type and number of actors, their linkages, and the resources available to them. Where much of the past support for the PV industry in Australia has been directed towards early research or market development, this research will provide information that could enable the design of policies that better facilitate innovation throughout the value chain and thus improve the impact of future policies on innovation.