Article
Thermodynamics
Xingyu Ren, Xiaoyu Ju, Michael J. Gollner
Summary: This study explores the impact of turbulence-induced instabilities on three-dimensional boundary-layer flames, showing that turbulence can trigger the formation of flame streaks, increase the spacing between streaks, and promote the transition of flames to a turbulent state. These findings offer new insights into the structure and heating dynamics of boundary-layer flames.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Hanwen Guo, Dong Xiang, Linyi Kong, Yunji Gao, Yuchun Zhang
Summary: This study experimentally evaluates the effects of slope angle and wind velocity on the spread of surface fire over a pine needle fuel bed. The results show that flame length, rate of spread, mass loss rate, and heat flux increase with increasing wind velocity and slope angle, while flame angle and fuel consumption efficiency vary in the opposite way. The study also analyzes the heat transfer mechanism and presents modified models for predicting radiation heat flux.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Xiaoyu Ju, Xingyu Ren, Evan Sluder, Lizhong Yang, Michael J. Gollner
Summary: Experiments were conducted to quantify the downstream heating effect of inclined fires, and a correlation model was established to predict the downstream heating of 2-D inclined flames in different terrains.
COMBUSTION AND FLAME
(2022)
Article
Engineering, Civil
Nan Zhu, Xinyan Huang, Jun Fang, Lizhong Yang, Longhua Hu
Summary: This study experimentally investigated the transitional behavior of flame spread under concurrent airflow, revealing that the transition process can be divided into three stages and the concurrent wind velocity has different impacts on flame spread rate and fuel regression rate.
FIRE SAFETY JOURNAL
(2021)
Article
Thermodynamics
Xiuqi Xi, Jose L. Torero, Augustin Guibaud
Summary: This paper presents a methodology that combines data assimilation and physical modeling to forecast fire growth. The method integrates an analytical solution for combustion and a CFD model for flow structure, and assimilates coefficients to improve the accuracy of fire spread rate and flame length predictions. Validation and convergence assessment demonstrate the robustness and potential of this approach.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Yuxuan Ma, Longhua Hu, Yajun Huang, Nan Zhu, Osamu Fujita
Summary: This paper investigates the sample thickness effect on the concurrent flame steady spread behavior, revealing that flame spread rate decreases with sample thickness and convection feedback is dominant. The study also shows that the equivalent pyrolysis length is larger for ceiling flame than floor flame, with different heat flux characteristics observed in the two configurations.
COMBUSTION AND FLAME
(2021)
Article
Polymer Science
Dushyant M. Chaudhari, Gregory J. Fiola, Stanislav Stoliarov
Summary: A new experimental setup was developed to study turbulent, buoyancy-driven flame spread on a corner wall. An empirical model relating spatially resolved heat feedback from the flame to the solid fuel surface and heat release rate (HRR) was developed and integrated with a detailed pyrolysis model. The simulations revealed the importance of the split between the convective and radiative portions of the flame heat flux, and showed that even relatively small uncertainties in the model parameters can produce large errors in the HRR predictions.
POLYMER DEGRADATION AND STABILITY
(2021)
Article
Thermodynamics
Nan Zhu, Yuxuan Ma, Yajun Huang, Jiang Lv, Xiepeng Sun, Longhua Hu
Summary: The effect of wind on vertically upward flame spread was studied on thermally thick PMMA slabs of different widths. It was found that wind changed the flame shape and decreased the flame spread rate. Mechanism analysis revealed the relationship between flame extending width, flame thickness, sample width, and wind velocity, and a theoretical model for flame spread in normal wind was proposed.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Xingyu Ren, Evan T. Sluder, Michael Heck, Torben P. Grumstrup, Mark A. Finney, Simo A. Makiharju, Michael J. Gollner
Summary: The study investigates the relationship of fire spread on inclined surfaces, finding that flames start attaching to the surface at around 18 degrees, with temperature and gas velocity affected by buoyancy. In the flame region, local flow velocity accelerates to a peak before slowing down, directly correlated with the angle of inclination and fireline intensity.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Ying Zhang, Qi Li, Kaixuan Tang, Yifan Lin
Summary: This study investigates the influence of inclination on flame spread on solid surfaces and improves the accuracy of predicting flame spread rate through detailed heat flux distribution. Numerical simulations of fire spread on corrugated cardboard surface at different angles were conducted using FireFOAM. The results show that the change in flow field structure, especially the presence of vortices, leads to flame attachment. Additionally, the flame attachment length increases with angle, especially at 0-20 degrees, and also increases with time. A modified fire spread model considering surface temperature is proposed, which effectively improves the accuracy of predicting fire spread rate at large inclinations.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Chemistry, Analytical
Matthew B. Dickinson, Cyle E. Wold, Bret W. Butler, Robert L. Kremens, Daniel Jimenez, Paul Sopko, Joseph J. O'Brien
Summary: Sensible energy is the primary mode of heat dissipation from combustion in wildland surface fires, yet it is not routinely measured. By using a bidirectional probe to measure flame velocity combined with gas temperature measurements, sensible heat fluxes can be estimated. In this study, horizontal flow velocities and energies were found to be larger than vertical velocities and energies, with sensible energies accounting for 75%, 54%, and 64% of fire energy.
Article
Construction & Building Technology
Yizhou Li, Zilong Wang, Xinyan Huang
Summary: The fire safety of building facade systems is a global issue, and the current facade fire standard tests vary from country to country, making it difficult to compare results. This study simulates different standard tests to explore the impact of heat flux and flame temperature on facade fire ignition and spread, and proposes a method to adjust the fire heat release rate for fair comparison of different test results. This research provides guidance for the future development and optimization of facade fire tests.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Ecology
Ali Edalati-nejad, Maryam Ghodrat, Sayyed Aboozar Fanaee, Albert Simeoni
Summary: This study investigated the impact of fire intensity on a wind-driven surface fire and an idealized structure downstream from the fire source through numerical simulation and experimental data validation. Results showed that increasing fire intensity led to increased crosswind velocity and raised temperatures near and on the building surface.
Article
Thermodynamics
Giovanni Di Cristina, Nicholas S. Skowronski, Albert Simeoni, Ali S. Rangwala, Seong-kyun Im
Summary: The study experimentally investigated the forced flow driven flame spread behavior along an array of discrete wooden fuel elements, categorizing the flame spread behavior into different regimes under various spacing-flow speed conditions and presenting them in a flammability map. Visual analysis of video data was used to describe the changing flame behavior and increasing discretization of the overall flame structure as the flow speed increases. An analysis of fluid mechanics and heat transfer conditions revealed a correlation between Stanton number (St) and Damkohler number (Da) with the onset of flame instabilities and quenching.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Forestry
Zakary Campbell-Lochrie, Carlos Walker-Ravena, Michael Gallagher, Nicholas Skowronski, Eric V. Mueller, Rory M. Hadden
Summary: This study systematically investigates the effect of fuel structure on heat transfer mechanisms within and above porous fuel beds. The results show that the peak radiant heat flux from in-bed combustion region is greater than from the above-bed flame front for all studied fuel conditions. However, the radiant heating from the above-bed flame increases with fuel loading. Therefore, fuel structure plays an important role in heat transfer mechanisms.
INTERNATIONAL JOURNAL OF WILDLAND FIRE
(2023)
Article
Thermodynamics
Sriram Bharath Hariharan, Hamed Farmahini Farahani, Ali S. Rangwala, Joseph L. Dowling, Elaine S. Oran, Michael J. Gollner
Summary: In-situ burning is effective for removing oil spills over water, but results in significant airborne particulate emissions. Research shows that fire whirls have higher burning efficiency and lower particulate emission rates compared to pool fires.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Xingyu Ren, Xiaoyu Ju, Michael J. Gollner
Summary: This study explores the impact of turbulence-induced instabilities on three-dimensional boundary-layer flames, showing that turbulence can trigger the formation of flame streaks, increase the spacing between streaks, and promote the transition of flames to a turbulent state. These findings offer new insights into the structure and heating dynamics of boundary-layer flames.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Jeanette Cobian-Iniguez, Franz Richter, Luca Camignani, Christina Liveretou, Hanyu Xiong, Scott Stephens, Mark Finney, Michael Gollner, Carlos Fernandez-Pello
Summary: This study investigates the smoldering behavior of woody fuel arrays at different porosities under the influence of wind through experiments. The results show that wind speed affects the burning rate and emissions, with higher wind speeds leading to increased burning rate and decreased CO/CO2 emissions. A theoretical analysis reveals that neither mass transfer nor heat transfer alone can explain the observed exponential decay in mass loss data.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Environmental
Sriram Bharath Hariharan, Hamed Farmahini Farahani, Ali S. Rangwala, Elaine S. Oran, Michael J. Gollner
Summary: The study investigated the influence of different air entrainment conditions on the emissions of particulate matter from fire whirls, finding differences between natural entrainment and forced entrainment conditions. By controlling the entrainment conditions effectively, it is possible to reduce the emissions of particulate matter.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Forestry
Priya Garg, Thomas Roche, Matthew Eden, Jacqueline Matz, Jessica M. Oakes, Chiara Bellini, Michael J. Gollner
Summary: The study investigates the impact of fuel moisture content on gaseous and particulate emissions from different combustion modes, showing varying trends for flaming and smouldering combustion. The results suggest that both combustion mode and fuel type play a role in emissions.
INTERNATIONAL JOURNAL OF WILDLAND FIRE
(2022)
Article
Thermodynamics
Xiaoyu Ju, Xingyu Ren, Evan Sluder, Lizhong Yang, Michael J. Gollner
Summary: Experiments were conducted to quantify the downstream heating effect of inclined fires, and a correlation model was established to predict the downstream heating of 2-D inclined flames in different terrains.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Weiqi Ji, Franz Richter, Michael J. Gollner, Sili Deng
Summary: This study proposes a framework for autonomously discovering biomass pyrolysis kinetic models from experimental data using chemical reaction neural networks and neural ordinary differential equations. The learned model is interpretable and can be translated into classical forms, facilitating chemical insights and integration into fire simulations. This research is of significant importance for predicting and modeling fire behavior.
COMBUSTION AND FLAME
(2022)
Article
Engineering, Civil
Siyan Wang, Shaorun Lin, Yanhui Liu, Xinyan Huang, Michael J. Gollner
Summary: This study investigates the smoldering ignition of tissue paper by a concentrated sunlight spot, finding that the minimum irradiation and ignition energy are positively correlated with the diameter of the spot area. Additionally, a heat transfer analysis reveals the dominant role of lateral conductive cooling in smaller spot ignition areas.
FIRE SAFETY JOURNAL
(2022)
Article
Engineering, Multidisciplinary
Maria Thomsen, Luca Carmignani, Andy Rodriguez, Charles Scudiere, Christina Liveretou, Carlos Fernandez-Pello, Michael Gollner, Sandra Olson, Paul Ferkul
Summary: This study aims to investigate the impact of external radiant heating on downward flame spread over cylindrical samples of polymethyl methacrylate (PMMA). Experimental results show that the flame spread rate is strongly correlated with the amount of radiant heating provided, and an analysis is presented to explain the relationship between flame spread rate, surface energy, and temperature. These findings can serve as a reference for future microgravity experiments conducted by NASA and provide insights for fire safety in space facilities.
Article
Engineering, Multidisciplinary
Franz Richter, Bryce Bathras, Julia Barbetta Duarte, Michael J. Gollner
Summary: Fires at the wildland-urban interface (WUI) have become more frequent and severe. This study examines the propensity of different wooden materials in various geometries to ignite when exposed to a pile of smoldering firebrands. The results show that the likelihood of ignition increases with wind speed, and the geometry of the wood significantly affects ignition risk.
Article
Thermodynamics
Xingyu Ren, Evan T. Sluder, Michael Heck, Torben P. Grumstrup, Mark A. Finney, Simo A. Makiharju, Michael J. Gollner
Summary: The study investigates the relationship of fire spread on inclined surfaces, finding that flames start attaching to the surface at around 18 degrees, with temperature and gas velocity affected by buoyancy. In the flame region, local flow velocity accelerates to a peak before slowing down, directly correlated with the angle of inclination and fireline intensity.
COMBUSTION AND FLAME
(2022)
Article
Forestry
Rebecca K. Miller, Franz Richter, Maria Theodori, Michael J. Gollner
Summary: The effective strategies of defensible spaces and home hardening are crucial to mitigate the risk of structural damage in wildfires, especially in the western United States. However, there is a policy gap where construction and landscaping professionals are not required to obtain credentials in wildfire risk mitigation. To address this issue, we propose a solution to enhance the competency of professionals in wildfire protection as communities expand in fire-prone areas.
INTERNATIONAL JOURNAL OF WILDLAND FIRE
(2022)
Article
Thermodynamics
Maria Thomsen, Juan Jose Cruz, Felipe Escudero, Andres Fuentes, Carlos Fernandez-Pello, Michael Gollner, David L. Urban, Gary A. Ruff
Summary: The spread of fire inside a spacecraft is a constant concern for space travel. This study aims to understand the combustion processes in microgravity and investigate the role of thermal radiation in flame spread. The experiments conducted as part of the NASA project Saffire IV provide valuable data and insights for future space facilities' fire safety.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Engineering, Civil
Priya Garg, Siyan Wang, Jessica M. Oakes, Chiara Bellini, Michael J. Gollner
Summary: During wildland fire events, firefighters are exposed to smoke containing particulate matter and gaseous emissions, which can pose serious respiratory and cardiovascular health risks. Respiratory protection (RP), such as masks, is crucial in mitigating this exposure. However, the effectiveness of different personal protective equipment (PPE) worn by firefighters is not well-researched. This study tested six different filtering materials against simulated wildland fire smoke and reported their effectiveness in removing both particulate matter and gases. Cloth bandanas, the most commonly worn RP material, showed minimal benefit, while other filter materials provided significant protection. N95, P95, and P100 filters were highly effective in removing particulate matter and partially effective in filtering certain gaseous species.
FIRE SAFETY JOURNAL
(2023)
Article
Engineering, Civil
Xiaoyu Ju, Mackenzie Conkling, Mohammadhadi Hajilou, Shaorun Lin, Farouk Mostafa, Anant Ayyar, Alexander Mcdowell, Michael Lisano, Michael J. Gollner
Summary: Firebrands play a critical role in the spread of wildland fires, especially in the wildland-urban interface. However, the mechanism behind fire spread by firebrands is not well understood. This study quantified the generation of firebrands from three typical WUI fuels and provided necessary data for modeling the spread of wildland fires.
FIRE SAFETY JOURNAL
(2023)
