权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Ignition propensity of structural materials exposed to firebrand in wildland-urban interface (WUI) fires

荒地-城市界面 (WUI) 火灾中暴露于火源的结构材料的着火倾向

基本信息

批准号：
1836428
负责人：
Ya-Ting Liao
金额：
$ 30万
依托单位：
Case Western Reserve University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1836428&HistoricalAwards=false
关键词：
Ignition propensity structural materials exposed

项目摘要

This project will characterize the ignition process of materials caused by firebrand attacks, a key mechanism of wildfire spread into Wildland-Urban Interface (WUI) communities. Firebrands are small burning pieces lofted by flame plumes and transported by ambient winds. Although they are small, firebrands can travel in large groups for long distances from the fire front. These firebrands can shower unto structures in WUI communities far from the wildfire itself and therefore pose serious threats to human lives and properties. In this project, lab-scale experiments and computational modeling will be used to systematically study such phenomena. By providing a better understanding of firebrand attacks, this project will promote the development of new testing standards for building codes and materials. This work will contribute to the effort in increasing the safety of structures at the wildland-urban interface, such as optimal geometry of structure for mitigating fire risks.For a combustible solid subjected to external heating, ignition depends not only on the total energy input but also on the spatial distribution of the heating. For ignition due to firebrand attack, the distribution of firebrands and their individual shapes, sizes, and contact areas with the target structure will determine the distribution of heat flux on the structure surface. Environmental conditions (e.g., background radiant heating and air flow speed) also have a significant effect on the kinetics of the burning firebrands and the interactions between firebrands and the target structure. The goal of this study is to obtain a fundamental understanding of how these parameters affect the ignition propensity of a structure material. A combination of lab-scale experiments and computational modeling will be used. The experiment will involve firebrands burning under the influence of air flow and external radiant heating. Temperatures, burning durations, and heat release rates of the burning brands, as well as the temperature of the substrate, will be analyzed. The ignition propensity of the fuel bed will be characterized according to firebrand attributes and environmental factors. A combustion model will also be developed for simulating the thermo-kinetic process of each aspect of the firebrand attack. The simulation results will provide detailed information about gases and solids during the combustion process, thus facilitating the interpretation of the experimental observation. The numerical simulation will also allow the investigation of the underlying physics of these processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目将描述由燃烧物攻击引起的材料的点燃过程，这是野火蔓延到荒地-城市界面（WUI）社区的关键机制。火把是由火焰羽流升起并由环境风传播的小燃烧物。虽然他们很小，但纵火犯可以大规模地从火灾前线长途跋涉。这些火把可以喷到远离野火本身的WUI社区的建筑物上，因此对人类生命和财产构成严重威胁。在这个项目中，实验室规模的实验和计算模型将被用来系统地研究这种现象。通过更好地了解煽动性攻击，该项目将促进制定建筑规范和材料的新测试标准。本文的工作将有助于提高野外-城市界面结构的安全性，例如优化结构的几何形状以降低火灾风险。对于可燃固体，受到外部加热，着火不仅取决于总能量输入，而且取决于加热的空间分布。对于因燃烧棒攻击引起的点火，燃烧棒的分布及其各自的形状、尺寸和与目标结构的接触面积将决定结构表面上的热通量分布。环境条件（例如，背景辐射加热和气流速度）也对燃烧的燃烧物的动力学以及燃烧物与目标结构之间的相互作用具有显著影响。本研究的目的是获得一个基本的了解这些参数如何影响结构材料的着火倾向。实验室规模的实验和计算建模的组合将被使用。实验将涉及在空气流动和外部辐射加热的影响下燃烧的火把。温度，燃烧持续时间，和燃烧品牌的热释放速率，以及基板的温度，将进行分析。燃料层的着火倾向将根据易燃物属性和环境因素来表征。还将开发一个燃烧模型，用于模拟燃烧器攻击各个方面的热动力学过程。模拟结果将提供有关燃烧过程中气体和固体的详细信息，从而便于解释实验观察。数值模拟还将允许调查这些过程的基本物理过程。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。