Chapter 12 12 Modeling Heating Effects Geoffry N. Mercer and Rodney O. Weber University of New So... more Chapter 12 12 Modeling Heating Effects Geoffry N. Mercer and Rodney O. Weber University of New South Wales at the Australian Defence Force ... heating of an idealized “cylin-drical tree”(for studies of tree stems and thick branches, as in Potter and Andresen, 2002), and the ...
The vegetation that burns in bushfires consists of water, pyrolys- able material that can ultimat... more The vegetation that burns in bushfires consists of water, pyrolys- able material that can ultimately burn as a gas, solid combustible material (char) that is capable only of surface burning and un- burnable material (ash). The vegetation is also a porous medium in which air, water vapour, pyrolysis products and combustion products flow past solid material. This flow is
ABSTRACT Miniaturization of conventional energy sources has so far proven to be a cumbersome proc... more ABSTRACT Miniaturization of conventional energy sources has so far proven to be a cumbersome process. A recently developed concept of thermopower waves has shown tremendous potential to reduce the dimensions of power sources while maintaining their energy generation capabilities. We demonstrate a tremendous improvement in the output for these thermopower wave based energy generation devices by implementing manganese dioxide (MnO2) as the core thermoelectric material. In this work, the thermoelectric MnO2 layer is used as a pathway for the propagation of thermopower waves that are generated as a result of an exothermic chemical reaction of a solid fuel (nitrocellulose). Such sell propagating thermopower waves result in exceptionally high voltage output on the order of 1.8 V and a specific power (power-to-mass ratio) on the order of 1.0 kW.kg(-1). The output voltage is at least 300% higher than any other thermopower wave system reported so far.
On a relatively large length-scale, the fire-fronts of wind-driven bushfires are sometimes seen t... more On a relatively large length-scale, the fire-fronts of wind-driven bushfires are sometimes seen to develop into curved shapes, suggesting that a linear fire-front becomes unstable. A mech- anism for this instability can be identified if the hot plume of the fire is considered to partially block the air-flow from be- low, while stratification of the atmosphere restricts upward dis- placement. Downwind of the fire this causes a speeding up of the component of the average horizontal flow in the direction normal to any part of the fire-front. The perturbation in the horizontal wind that results from a perturbed shape of the fire- front shows an increase in the flow of air into the fire at more advanced parts of the front, normally resulting in an increased burning rate which would therefore increase the size of the per- turbation.
This paper is an introduction to the special issue of the Journal of Engineering Mathematics on t... more This paper is an introduction to the special issue of the Journal of Engineering Mathematics on the mathematical modelling of the thermal-explosion phenomenon. The issue includes six papers covering a wide range of current studies in the field. This introductory paper is written to bring a description of the phenomenon to readers with a background in mathematical modelling and computational
Chapter 12 12 Modeling Heating Effects Geoffry N. Mercer and Rodney O. Weber University of New So... more Chapter 12 12 Modeling Heating Effects Geoffry N. Mercer and Rodney O. Weber University of New South Wales at the Australian Defence Force ... heating of an idealized “cylin-drical tree”(for studies of tree stems and thick branches, as in Potter and Andresen, 2002), and the ...
The vegetation that burns in bushfires consists of water, pyrolys- able material that can ultimat... more The vegetation that burns in bushfires consists of water, pyrolys- able material that can ultimately burn as a gas, solid combustible material (char) that is capable only of surface burning and un- burnable material (ash). The vegetation is also a porous medium in which air, water vapour, pyrolysis products and combustion products flow past solid material. This flow is
ABSTRACT Miniaturization of conventional energy sources has so far proven to be a cumbersome proc... more ABSTRACT Miniaturization of conventional energy sources has so far proven to be a cumbersome process. A recently developed concept of thermopower waves has shown tremendous potential to reduce the dimensions of power sources while maintaining their energy generation capabilities. We demonstrate a tremendous improvement in the output for these thermopower wave based energy generation devices by implementing manganese dioxide (MnO2) as the core thermoelectric material. In this work, the thermoelectric MnO2 layer is used as a pathway for the propagation of thermopower waves that are generated as a result of an exothermic chemical reaction of a solid fuel (nitrocellulose). Such sell propagating thermopower waves result in exceptionally high voltage output on the order of 1.8 V and a specific power (power-to-mass ratio) on the order of 1.0 kW.kg(-1). The output voltage is at least 300% higher than any other thermopower wave system reported so far.
On a relatively large length-scale, the fire-fronts of wind-driven bushfires are sometimes seen t... more On a relatively large length-scale, the fire-fronts of wind-driven bushfires are sometimes seen to develop into curved shapes, suggesting that a linear fire-front becomes unstable. A mech- anism for this instability can be identified if the hot plume of the fire is considered to partially block the air-flow from be- low, while stratification of the atmosphere restricts upward dis- placement. Downwind of the fire this causes a speeding up of the component of the average horizontal flow in the direction normal to any part of the fire-front. The perturbation in the horizontal wind that results from a perturbed shape of the fire- front shows an increase in the flow of air into the fire at more advanced parts of the front, normally resulting in an increased burning rate which would therefore increase the size of the per- turbation.
This paper is an introduction to the special issue of the Journal of Engineering Mathematics on t... more This paper is an introduction to the special issue of the Journal of Engineering Mathematics on the mathematical modelling of the thermal-explosion phenomenon. The issue includes six papers covering a wide range of current studies in the field. This introductory paper is written to bring a description of the phenomenon to readers with a background in mathematical modelling and computational
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Papers by Rodney Weber