ERI: Understanding the Role of Non-steady Wind Gusts in Wildfire Spread

ERI：了解不稳定阵风在野火蔓延中的作用

• 批准号: 2138619
• 负责人: James Urban
• 金额: $ 20万
• 依托单位: Worcester Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-15 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2138619&HistoricalAwards=false
• 关键词: ERI; Understanding; Role; Non; steady

Increased extreme fire behavior (both prevalence and severity) has caused substantial loss of property and human life, generated air pollution over large areas, and displaced large numbers of people. Accurate prediction of wildfire growth is vital for fire response (firefighting and evacuations) as well as preventative measures (prescribed burning and community hardening). This project seeks to better defend against these negative consequences of wildfires by better understanding the role of non-steady wind on their growth. Two physical mechanisms for fire growth are studied: flame-driven fire spread and firebrand spotting. Flame-driven fire spread is the process by which flames heat and ignite nearby fuel and firebrand spotting is the process by which burning debris (firebrands) are transported by the wind and fire gases to fuels which they may ignite. Nearly all prior fundamental studies of these processes have focused on fire behavior under steady conditions and have ignored the role of non-steady wind such as gusts. For firebrand generation from burning vegetation, the role of wind is known to be important, but it has not been fully characterized. This project examines whether fire spread and firebrand generation behavior can be explained with steady-flow results or if non-steady wind produces more extreme fire behavior. During the project, educational modules on wildfire topics related to the research will be incorporated into one graduate and one undergraduate course. Through these modules and student involvement in the research the PI will help prepare an engineering workforce knowledgeable about wildland and wildland-urban interface fire and cultivate interest in these areas of Fire Protection Engineering.This project will examine the physical mechanisms by which non-steady wind interacts with wildfire behavior, specifically flame-driven wildfire spread and firebrand spotting, while also making novel measurements of these wildfire behaviors using imaging methods. The motivation for the project is to facilitate improvement of physical modelling of wildfire spread. Current models do not accurately predict fire spread in all situations. Wind strongly influences wildfire spread through intermittent convective heating of fine fuel particles while also contributing to firebrand spotting. The role of transient wind (i.e., gusts) has not been examined in these models. The project addresses research needs identified by the community for firebrand spotting using new experimental methodologies to characterize firebrand generation and more comprehensive characterization of wildfire spread to enable verifiable modelling of wildfire spread to address the gap between prediction with current models and observed behavior.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.

极端火灾行为的增加（包括流行程度和严重程度）造成了巨大的财产损失和人类生命，造成了大面积的空气污染，并使大量人流离失所。野火增长的准确预测对于火灾响应（消防和疏散）以及预防措施（规定的燃烧和社区加固）至关重要。该项目旨在通过更好地了解不稳定风对野火生长的作用，更好地抵御野火的这些负面后果。研究了火焰生长的两种物理机制：火焰驱动的火焰蔓延和火焰标记。由火焰驱动的火灾蔓延是火焰加热并点燃附近燃料的过程，而着火标的发现是燃烧的碎片（着火标的）被风和火焰气体输送到燃料上并可能点燃的过程。几乎所有关于这些过程的基础研究都集中在稳定条件下的火灾行为上，而忽略了非稳定风（如阵风）的作用。对于燃烧植被产生的火种，众所周知风的作用是重要的，但它还没有得到充分的表征。该项目考察了火灾蔓延和火种产生行为是否可以用稳定流动的结果来解释，或者非稳定风是否会产生更极端的火灾行为。在项目期间，与研究相关的野火主题的教育模块将被纳入一门研究生和一门本科课程。通过这些模块和学生参与研究，PI将帮助培养一支了解荒地和荒地-城市界面火灾的工程队伍，并培养对这些领域的消防工程的兴趣。该项目将研究非稳定风与野火行为相互作用的物理机制，特别是火焰驱动的野火传播和火种发现，同时也使用成像方法对这些野火行为进行新的测量。该项目的动机是促进改进野火传播的物理模型。目前的模型不能准确地预测所有情况下的火灾蔓延。风通过对细燃料颗粒的间歇对流加热强烈影响野火的蔓延，同时也有助于火种的发现。在这些模型中，暂态风（即阵风）的作用尚未得到检验。该项目解决了社区确定的研究需求，即使用新的实验方法来表征火种产生，并更全面地表征野火传播，从而实现野火传播的可验证建模，以解决当前模型预测与观察行为之间的差距。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。