Firebrand pile ignition of adjacent materials requires an in-depth understanding of heat transfer and flow profile within the firebrand pile. Modeling the firebrand pile as a fibrous porous medium, this study identified a porosity-permeability correlation that accurately describes the transport properties of a firebrand pile. The conduction-based model and Kozeny-Carman model were identified and examined by experiment, where firebrand porosity and permeability were collected with a wind tunnel. The conduction-based model was more stable and more accurate in the porosity range of interest. Pore network models were developed for the simulation of flow profiles utilizing the permeability data collected. The non-uniform network, which better represents a randomly stack firebrand pile, resulted in a more complex multidimensional flow within the pile. / Master of Science / Firebrands are known to be one of the primary ways wildfires can spread. They are mostly small pieces of flammable materials originating from vegetation or wooden structures that can be carried by wind ahead of the fire. The accumulation of firebrands on flammable materials tends to create ignitions, which calls for an in-depth understanding of temperature and airflow within the firebrand pile. Simplifying the firebrand pile as a porous medium, this study identified a relationship between how much void is present in the pile and the resistance of airflow of a firebrand pile. The conduction-based model and Kozeny-Carman model were identified and examined by experiment with a wind tunnel. The conduction-based model was determined to better describe the relationship. Pore network models were developed for the simulation of flow through the firebrand pile utilizing the data collected in the experiment, which provided an understanding of how airflow behaves inside the pile. A non-uniform flow network inside the pile led to a more complex, multidimensional flow through the firebrand pile.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/117264 |
| Date | 21 December 2023 |
| Creators | Wu, Ditong |
| Contributors | Mechanical Engineering, Lattimer, Brian Y., Meadows, Joseph, Palmore, John A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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