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(2012) Ramachandran, Darshillan; Doig, G.C.Conference PaperThe flow around an exposed rotating wheel, such as those on a Formula 1 car, is complex in nature; experimental investigation using wind tunnel is expensive and may not be able to show intricate flow features. Computational Fluid Dynamics (CFD) can enable numerical solutions of flow over an exposed wheel, but due to issues of computational cost only steady-state Reynolds Averaged Navier Stokes (RANS) methods are commonly used. In the present work, an exposed rotating wheel in contact with a moving ground was modeled using unsteady RANS, Large Eddy Simulation (LES) and Detached Eddy Simulation (DES). These transient methods demonstrate more intricate details of the flow not seen in steady state simulations. In addition, LES and DES more accurately resolves the large scale eddies that will be apparent especially in the wheel wake and enable the flow field to be understood in a more complete way.
Non-contact gas turbine blade vibration measurement from casing pressure and vibration signals – A review(2010) Forbes, Gareth Llewellyn; Randall, Robert BondConference PaperThis paper presents a summary of a recent research program, focusing on a new method of non contact gas turbine blade vibration measurement using casing pressure and vibration signals. Currently the dominant method of non contact measurement of turbine blade vibrations employs the use of a number of proximity probes located around the engine periphery measuring the blade tip (arrival) time (BTT). Despite the increasing ability of this method there still exist some limitations, viz: the requirement of a large number of sensors for each engine stage, difficulties in dealing with multiple excitation frequencies, sensors being located in the gas path, and the inability to directly measure the natural frequency of a given blade. Simulations established with a physics based model along with experimental measurements are presented in this paper, using internal pressure and casing vibration measurements, which have the potential to rectify some of these problems.
(2010) Kanapathipillai, Sangarapillai; Feng, NingshengConference PaperDesign teaching in mechanical engineering has two features which distinguish it from many other teaching areas. First, the majority of students have little or no background in technology and practical design. Second, virtually all design learning comes through the development of conceptual understanding, rather than from the learning of declarative knowledge. The objective of teaching mechanical engineering design is to provide a learning context in which students will achieve a basic level of competence in design. The challenge, then, for design teachers is to ensure that the learning context – the curriculum, teaching methods, and assessment provisions – is appropriate to the development of conceptual understanding of the design process, and through this, achieve the goal of design competence. The most important and yet most difficult teaching goal is to bring the conceptual change in students’ understanding of the fundamental features of the discipline being studied. The focus of this paper is to look at some of the aspects associated with the teaching mechanical engineering design in new environment in which engineering schools are subject to resource constraints. The results indicate that there is a need for a closer look at teaching methods and assessment practices.
(2010) Cole, Fletcher; Cox, Shane; Frances, MaudeConference PaperAn opportunity to explore the topic of data usages is presented by the collaborative research being undertaken by a federation of applied science research units affiliated with a number of different Australian research organizations (the Cluster). The research aims to investigate how members of the collaboration understand and work with data in their day-to-day practice.
Relationship between the pressure at the casing wall and at the blade tip for a vibrating turbine blade(2010) Alshroof, Osama; Forbes, Gareth Llewellyn; Randall, Robert BondConference PaperA recent research program has identified the possibility of using the analysis of casing wall pressures in the indirect measurement of gas turbine rotor blade vibration amplitudes. Analytical modelling of the casing wall pressures and reconstruction of rotor blade vibration amplitudes from the analysis of these simulated pressure signals have shown potential advantages over current non-contact rotor blade vibration measurement methods. However, the modelling made some fundamental assumptions about the casing wall pressure. One of the assumptions made was that the pressure at the blade tip is not significantly different from that measured across the clearance gap at the casing wall. This fluid-structure hypothesis is investigated in this paper. Unsteady computational fluid dynamic modelling of the flow conditions around the blade surface, combined with the blade structural motion, is performed numerically, and the distributions of the pressure across the rotor blade tip and casing clearance gap are investigated and reported.
(2010) Forbes, Gareth Llewellyn; Alshroof, Osama; Randall, Robert BondConference PaperA recent research program has identified the possibility of using the analysis of casing wall pressures in the direct measurement of gas turbine rotor blade vibration amplitudes. Currently the dominant method of non-contact measurement of gas turbine blade vibrations employs the use of a number of proximity probes located around the engine periphery measuring the blade tip (arrival) time (BTT). Despite the increasing ability of this method there still exist some limitations, viz: the requirement of a large number of sensors for each engine stage, sensitivity to sensor location, difficulties in dealing with multiple excitation frequencies and sensors being located in the gas path. Analytical modelling of the casing wall pressures and reconstruction of rotor blade vibration amplitudes from the analysis of these simulated pressure signals has shown significant improvement over current non-contact rotor blade vibration measurement limitations by requiring only a limited number of sensors and providing robust rotor blade vibration amplitude estimates in the presence of simulated measurement noise. However, this modelling was conducted with some fundamental assumptions about the casing wall pressures being made. One of these assumptions presumed that during blade motion the pressure profile around the rotor blades follows the blade’s motion while it oscillates around its equilibrium position. This assumption is investigated in this paper through the numerical modelling of the fully coupled two-way rotor blade motion and fluid pressure interaction.
Radio frequency readout of electrically detected magnetic resonance in phosphorus-doped silicon MOSFETs(2010) Willems van Beveren, Laurens; Huebl, H.; Starrett, Robert; Morello, AndreaConference PaperWe demonstrate radio frequency (RF) readout of electrically detected magnetic resonance in phosphorus-doped silicon metal-oxide field-effecttransistors (MOSFETs), operated at liquid helium temperatures. For the first time, the Si:P hyperfine lines have been observed using radio frequency reflectometry, which is promising for high-bandwidth operation and possibly time-resolved detection of spin resonance in donor-based semiconductor devices. Here we present the effect of microwave (MW) power and MOSFET biasing conditions on the EDMR signals.