Science Collected Works - Research Publications
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ItemNo Preview AvailableLarge-eddy simulation of methane direct injection using the full injector geometry(ELSEVIER SCI LTD, 2021-04-15)
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ItemImaging the ignition of dense, inhomogenous liquid fuel sprays at elevated temperatures and pressures(The University of Queensland, 2020)This paper investigates the forced ignition of inhomogeneous, dense liquid fuel sprays. The fuel spray is pure n-Heptane, injected with a prototype gasoline direct injector designed by Delphi for the Engine Combustion Network’s Spray G research. This spray is ignited by a laser spark, delivered by a custombuilt high precision laser traverse system. The spray ignition process is recorded with a high-repetition rate schlieren imaging system. The impact of changes in chamber pressure and temperature on ignition probability statistics are investigated. Ignition probability is reduced by increasing chamber pressure and promoted by increasing chamber temperature. At a constant laminar flame speed, the impact of chamber temperature increase is greater than that of chamber pressure increase.
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ItemAnnihilation events topology and their generated sound in turbulent premixed flames(Elsevier, 2019-06-01)The Combustion Institute This paper studies the contribution of flame annihilation events to the sound radiated by turbulent, premixed flames. Previously published direct numerical simulation (DNS) datasets of stoichiometric and lean (ϕ=0.7) flames (Haghiri et al. 2018) are first examined using an efficient formulation of the method of Griffiths et al. (2015) to identify the annihilation events. Four classes of annihilation event are observed. Three of these - pocket burn-out, tunnel closure and tunnel formation - were defined by Griffiths et al. A ‘multi-feature’ event is also defined in this paper as any combination of the other three annihilation events occurring close enough such that their radiated sound can be considered as originating from a single event. Further post-processing of these stoichiometric and lean datasets shows that the fluctuations in heat release rate associated with these 4 observed types of annihilation events are responsible for the broadband sound radiated by both flames. This, in turn, suggests that flame annihilation is the physical mechanism by which air-fuel ratio affects the radiated sound amplitude at high frequencies. This result is supported by previous works which have shown that the sound radiated from individual annihilation events scales with the laminar flame speed and the temperature ratio.
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ItemSubmission to the Department of Environment and Energy in response to their “Better fuel for cleaner air” discussion paper(Clean Air and Urban Landscapes Hub, 2017)The Clean Air and Urban Landscapes Hub and the Melbourne Energy Institute welcome the opportunity to comment on the ‘Better fuel for cleaner air’ discussion paper, and the proposed changes to the Fuel Quality Standards Act 2000 and associated legislation. These two groups have expertise in several areas that are relevant to this paper: air quality, public health, energy policy and resource economics and vehicle fuels and emissions. We would therefore welcome further discussion with the Department should this be of interest. Our submission first considers the motivation of this Paper. While Australian air quality conforms to international standards, recent research1 shows that significant health impacts still occur at pollution levels experienced in Australia. The costs of air pollution to society have been put on a par with smoking and obesity. Air pollution due to vehicle emissions is estimated to have caused 1715 deaths in Australia in 20152 , larger than the national road toll of 1205 in 20153 . Appendix A to this submission contains a detailed discussion of these health impacts. We submit that a review of the Fuel Quality Standards Act 2000 and associated legislation should therefore prioritise this cost of the health impacts of vehicle emissions. To this end this submission primarily addresses Question Sets 1 and 6, and the Questions relating to the fuel, automotive and marine diesel standards. While making specific recommendations relevant to the Fuel Quality Standards Act 2000, we also submit that the comprehensive package of measures should contain additional regulations, at both Australian Government and state government levels, concerning energy infrastructure, motor vehicles and other engines, and driver behaviour. Furthermore, additional government action directed towards increasing public awareness and supporting better collection of air quality data are important.