| 项目编号: | 1603316
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| 项目名称: | Collaborative Research: Merging of Horizontally and Vertically Separated Flames in Wildland Fires |
| 作者: | Thomas Fletcher
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| 承担单位: | Brigham Young University
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| 批准年: | 2016
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| 开始日期: | 2016-08-15
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| 结束日期: | 2019-07-31
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| 资助金额: | 180001
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Engineering - Chemical, Bioengineering, Environmental, and Transport Systems
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| 英文关键词: | flame
; flame-merging
; flame behavior
; three-dimensional flame-merging
; flame height
; wildland fire
; single flame
; small-scale experiment
; large flame
; flames-merging behavior
; correlation
; small-scale
; flame-merging behavior
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| 英文摘要: | 1603316 - Fletcher
1603947 - Mahalingam
This project will study how two or more flames in close proximity merge into a single flame. The immediate application for this information is wildland fires in live shrubs, like in the California chaparral. Living vegetation is characterized by its ability to hold large quantity of moisture, unlike dead vegetation. A few leaves are initially ignited, and the flames from the separate leaves merge into one large flame. In a similar manner, flames from individual shrubs merge to often form a more intense fire, capable of spreading faster. For example, flame heights from individual leaves are only 2 to 5 cm, but flames from shrubs may reach heights of 10 to 12 m due to flame merging. Small-scale experiments will be performed on leaves, wood dowels, or popsicle sticks in 3-D geometries to examine how spacing affects flames-merging behavior. Correlations that describe flame-merging will be based on spacing, heat release, and other variables, and then compared with physics-based fluid dynamics simulations. The simulations will further enable direct investigation of merged flame behavior in shrubs and between adjacent shrubs. Generalized correlations of flame-merging behavior derived from the combined experimental and modeling activities can possibly be applied to fires in buildings, factories, fuel piles, and other combustible materials. Findings from this research will be used to develop educational materials for STEM educators and students.
Flame merging has been studied for jets or pool fires spaced in a horizontal plane, and correlations for flame merging behavior have been developed. However, three-dimensional flame-merging is important for ignition of live shrubs, as well as building fires. Small-scale experiments will be performed on solid fuel elements such as leaves, wood dowels, or popsicle sticks as a function of vertical and horizontal separation distance. Experiments will be performed with and without wind. Flame behavior will be monitored with video and IR cameras, and correlations of flame behavior will be developed. Physics-based modeling of the small-scale experiments will be performed to help identify the most important mechanisms for flame merging. The simulations will then be extended to describe flame merging of adjacent shrubs, with and without wind. The scalability of the empirical correlations will be determined by comparison with the multiple shrub simulations. It is expected that such correlations of flame merging behavior will provide a reasonable alternative to time-consuming computational fluid dynamics simulation of large landscape fires. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/91417
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| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
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| Recommended Citation: | |
Thomas Fletcher. Collaborative Research: Merging of Horizontally and Vertically Separated Flames in Wildland Fires. 2016-01-01.
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