In this paper, we establish a mathematical model of the forest fire spread process based on a partial differential equation. We describe the distribution of time field and velocity field in the whole two-dimensional s...In this paper, we establish a mathematical model of the forest fire spread process based on a partial differential equation. We describe the distribution of time field and velocity field in the whole two-dimensional space by vector field theory. And we obtain a continuous algorithm to predict the dynamic behavior of forest fire spread in a short time. We use the algorithm to interpolate the fire boundary by cubic non-uniform rational B-spline closed curve. The fire boundary curve at any time can be simulated by solving the Eikonal equation. The model is tested in theory and in practice. The results show that the model has good accuracy and stability, and it’s compatible with most of the existing models, such as the elliptic model and the cellular automata model.展开更多
Mathematical model of forest fire was based on an analysis of known experimental data and using concept and methods from reactive media mechanics. In this paper the assignment and theoretical investigations of the pro...Mathematical model of forest fire was based on an analysis of known experimental data and using concept and methods from reactive media mechanics. In this paper the assignment and theoretical investigations of the problems of crown forest fire spread in windy condition were carried out. In this context, a study—mathematical modeling—of the conditions of forest fire spreading that would make it possible to obtain a detailed picture of the change in the temperature and component concentration fields with time, and determine as well as the limiting condition of fire propagation in forest with fire break.展开更多
The apartment fire tests comprise a set of two full-scale fire experiments in a dwelling building made from pre-fabricated concrete elements in April 2013. Two apartments were nearly identically furnished and fully in...The apartment fire tests comprise a set of two full-scale fire experiments in a dwelling building made from pre-fabricated concrete elements in April 2013. Two apartments were nearly identically furnished and fully instrumented with thermocouples, video cameras and gas extraction probes. The apartments were ignited successively whereupon the fire in the second apartment developed freely to post-flashover conditions and got the main focus in this report. The apartment was completely furnished with contemporary furniture and objects, and had an average fire load density for residential occupancy. A full description of the fire load, ventilation conditions and instrumentation are provided. The focus of this report is primarily to obtain conclusions on the horizontal spread of smoke throughout the apartment during the fire growth period. Velocities of smoke spreading were measured to be in the range below 0.05 m/s which means that the smoke migrated over the longest distance throughout the apartment for about 3 to 4 minutes while the flame did not leave the initial fire room. The main aim of the experiments was to collect a comprehensive set of data from a realistic and contemporary fire scenario to validate numerical simulations.展开更多
Traditional wildfire spread prediction models often struggle to simulate fire propagation accurately in complex terrain or under strong wind conditions due to their semi-empirical nature and simplified treatment of fi...Traditional wildfire spread prediction models often struggle to simulate fire propagation accurately in complex terrain or under strong wind conditions due to their semi-empirical nature and simplified treatment of fire-atmosphere interactions.This study presents a novel rapid fire spread model that integrates Briggs'buoyant plume theory,the Rothermel fire spread model,and Huygens'principle of wave propagation.The model is designed to simulate fire behavior in grasslands with complex terrain,enabling detailed representation of fire front dynamics.By analytically solving flame plume equations,the model quantifies the combustion heat production and its impact on surrounding wind fields through buoyant lifting effects.This innovative two-way coupling of atmosphere-fire interactions enhances the model's ability to simulate fire behavior under various environmental conditions.The model incorporates multiple factors,such as the wind speed,terrain,flame plume entrainment,fuel moisture content,packing ratio,and effective flame width,overcoming the limitations of traditional models in accurately capturing the shape of fire fronts.Validation through numerical simulations demonstrates that the model effectively reproduces both the temporal and spatial evolution of fire fronts across different wind and terrain conditions.In benchmark tests with a 100-meter ignition line,the model shows remarkable agreement with fully-coupled dynamic simulations,with a mere-10.38%deviation in fire spread rate while accurately replicating fire front patterns.The proposed model offers high computational efficiency and can serve as a valuable tool for wildfire risk assessment and emergency response.展开更多
Fires in the railway trains are prone to cause large numbers of casualties,serious economic losses,and huge negative social impacts.The railway train carriage is a special confined built environment,where the pyrolysi...Fires in the railway trains are prone to cause large numbers of casualties,serious economic losses,and huge negative social impacts.The railway train carriage is a special confined built environment,where the pyrolysis,combustion,and fire spread process are different from those fire accidents in open space.Identifying the fire characteristics of the railway train carriages is the key issue to determine the fire prevention and control strategy.Therefore,this paper attempts to assess and identify the characteristics of pyrolysis,combustion,and fire spread of railway trains based on the exising research.This review documents the pyrolysis and combustion characteristics of single train material and the combustible module,summarizes the heat release rate(HRR)calculation methods and the HRR profile for different types of trains,as well as introduces the research progress in the flame spread and flashover.The main gaps and issues to be solved in terms of the effects of train speed,altitudes,and application of new energy trains are further discussed.展开更多
Old towns like Lijiang have enormous historic, artistic, and architectural value. The buildings in such old towns are usually made of highly combustible materials, such as wood and grass. If a fire breaks out, it will...Old towns like Lijiang have enormous historic, artistic, and architectural value. The buildings in such old towns are usually made of highly combustible materials, such as wood and grass. If a fire breaks out, it will spread to multiple buildings, so fire spreading and controlling in old towns need to be studied. This paper presents a fire spread model for old towns based on cellular automaton. The cellular automaton rules were set according to historical fire data in empirical formulas. The model also considered the effects of cli- mate. The simulation results were visualized in a geography information system. An example of a fire spread in Lijiang was investigated with the results showing that this model provides a realistic tool for predicting fire spread in old towns. Fire brigades can use this tool to predict when and how a fire spreads to minimize the losses.展开更多
This paper relates to the semi-empirical model based on fire field energy balance and the physical model based on land temperature, aiming to provide a practical way of describing fire spread. Fire spread is determine...This paper relates to the semi-empirical model based on fire field energy balance and the physical model based on land temperature, aiming to provide a practical way of describing fire spread. Fire spread is determined by the characteristics of combustible materials and the agency of meteorological factors and terrains. Combustible materials, such as surface area, have no featured scale, yet the process of forest fire spread contains the self-replicating feature, both of which contribute to the self-similarity of fire spread. Consequently, fire behavior can be described by fractal geometry. In this research, we select Wuchagou forest in Da Hinggan Mountains as the experimental site where a forest fire took place three years ago. The forest fire was detected on low-resolution NOAA-AVHRR images, and fire spread was simulated on high-resolution TM images as another attempt to merge information. Based on remote sensing and GIS, we adopted the method of limited spreading lumping (DLA) to describe growing phenomenon to simulate the dynamic process of fire spread and adjusting shape of the result of fire simulation by the scale rule. As a result, the simulated fire and the actual fire manifest the self-similarity in their spreading shapes as well as the quantitative similarity in their areas.展开更多
Since serious fire occurred frequently in recent years, fire safety of high-rise building has attracted extensive attention. A National Basic Research Program （973 program） of China has been set up by Ministry of Sc...Since serious fire occurred frequently in recent years, fire safety of high-rise building has attracted extensive attention. A National Basic Research Program （973 program） of China has been set up by Ministry of Science and Technology （MOST） of China in 2012 to meet the research requirements of fire safety in high-rise buildings. This paper reviews the current state of art of research on fire dynamics of high-rise buildings, including the up-to-date progress of this project. The following three subjects on fire dynamics of high-rise buildings are addressed in this review： the ejected flame and fire plume behavior over facade out of the compartment window, the flame spread behavior over facade thermal insulation materiMs, and the buoyancy-driven smoke transportation characteristics along long vertical channels in high-rise buildings. Prospective future works are discussed and summarized.展开更多
Eruptive fires are one of the main causes of human losses in forest fire fighting. The sudden change in fire behaviour due to a fire eruption is extremely dangerous for fire-fighters because it is unpredictable. Very ...Eruptive fires are one of the main causes of human losses in forest fire fighting. The sudden change in fire behaviour due to a fire eruption is extremely dangerous for fire-fighters because it is unpredictable. Very little literature is available to support either modelling or occurrence prediction for this phenomenon. In this study, an unsteady physical model of fire spread is detailed, which describes the initiation and development of eruptive fires with an induced wind sub-model. The latter phenomenon is proposed as the mainspring of fire eruptions. Induced wind is proportional to the rate of spread and the rate of spread is in a non-linear relationship with induced wind. This feedback can converge or diverge depending on the conditions. The model allows both explaining why an eruption can occur and predicting explicitly its occurrence according to meteorological conditions, topographic parameters, fuel bed properties and fire front width. The model is tested by comparing its results to a set of experiments carried out at laboratory scale and during an outdoor wildfire, the Kornati accident.展开更多
The first aim of this work is to provide an analytical expression to calculate the rate of spread of surface fires under no wind and no slope conditions. A previous simplified model was improved for this particular ca...The first aim of this work is to provide an analytical expression to calculate the rate of spread of surface fires under no wind and no slope conditions. A previous simplified model was improved for this particular case of fire propagation. The test of this proposed model was performed by using two complete sets of experimental results with several fuel beds and variable parameters such as moisture content or bulk density. The second aim of this article is to highlight two conditions that allow stopping a fire： the low leaf area and the high value of the moisture content.展开更多
Fire is one of the extreme loading events that a building may experience during its service life and can have severe consequences on the safety of its occupants,first responders,and the structure.Steel framed building...Fire is one of the extreme loading events that a building may experience during its service life and can have severe consequences on the safety of its occupants,first responders,and the structure.Steel framed buildings under severe fires can experience high levels of instability at a local or global level,which in turn can lead to the partial or progressive collapse of the structure.However,in current practice,fire resistance of structures is obtained without due consideration to a number of critical factors,and this is mainly due to the high level of complexity in undertaking advanced analysis of structures under fire exposure.This paper presents a parametric study on a ten-story braced steel framed building subjected to fire exposure wherein six different parameters are evaluated:fire severity,fire spread,load paths,temperature-induced creep,local instability,and analysis regime.Results from validated finite element models are utilized to evaluate the influence of the different parameters and recommend critical parameters to be incorporated in the analysis.Results show that the susceptibility of fire-induced progressive collapse significantly depends on the severity of the fire exposure scenario,including fire intensity,fire spread,and extent of burning.Also,accounting for the full effects of transient creep in fire-induced progressive collapse analysis is needed to obtain conservative failure times under severe to very intense fire exposure.Additionally,results from the parametric study infer that the sectional classification of a steel section based on local instability can alter under fire exposure and this effect is more critical in steel columns located in the higher stories of the building;a nonslender column at ambient conditions can transform to a slender section at elevated temperatures.This can induce temperature-induced local instability in the column and lead to an early onset of instability at member and structural levels.展开更多
文摘In this paper, we establish a mathematical model of the forest fire spread process based on a partial differential equation. We describe the distribution of time field and velocity field in the whole two-dimensional space by vector field theory. And we obtain a continuous algorithm to predict the dynamic behavior of forest fire spread in a short time. We use the algorithm to interpolate the fire boundary by cubic non-uniform rational B-spline closed curve. The fire boundary curve at any time can be simulated by solving the Eikonal equation. The model is tested in theory and in practice. The results show that the model has good accuracy and stability, and it’s compatible with most of the existing models, such as the elliptic model and the cellular automata model.
文摘Mathematical model of forest fire was based on an analysis of known experimental data and using concept and methods from reactive media mechanics. In this paper the assignment and theoretical investigations of the problems of crown forest fire spread in windy condition were carried out. In this context, a study—mathematical modeling—of the conditions of forest fire spreading that would make it possible to obtain a detailed picture of the change in the temperature and component concentration fields with time, and determine as well as the limiting condition of fire propagation in forest with fire break.
文摘The apartment fire tests comprise a set of two full-scale fire experiments in a dwelling building made from pre-fabricated concrete elements in April 2013. Two apartments were nearly identically furnished and fully instrumented with thermocouples, video cameras and gas extraction probes. The apartments were ignited successively whereupon the fire in the second apartment developed freely to post-flashover conditions and got the main focus in this report. The apartment was completely furnished with contemporary furniture and objects, and had an average fire load density for residential occupancy. A full description of the fire load, ventilation conditions and instrumentation are provided. The focus of this report is primarily to obtain conclusions on the horizontal spread of smoke throughout the apartment during the fire growth period. Velocities of smoke spreading were measured to be in the range below 0.05 m/s which means that the smoke migrated over the longest distance throughout the apartment for about 3 to 4 minutes while the flame did not leave the initial fire room. The main aim of the experiments was to collect a comprehensive set of data from a realistic and contemporary fire scenario to validate numerical simulations.
基金supported by the Innovation and Development Project of China Meteorological Administration(Grant No.CXFZ2024Q010)the National Natural Science Foundation of China(Grant Nos.42205075 and 42330608)+2 种基金the Beijing Natural Science Foundation(Grant No.8252025)supported by the youth innovation team of China Meteorological Administration(Grant No.CMA2024QN12)supported by the Key Innovation Team of China Meteorological Administration Innovation Team(Grant No.CMA2022ZD09)。
文摘Traditional wildfire spread prediction models often struggle to simulate fire propagation accurately in complex terrain or under strong wind conditions due to their semi-empirical nature and simplified treatment of fire-atmosphere interactions.This study presents a novel rapid fire spread model that integrates Briggs'buoyant plume theory,the Rothermel fire spread model,and Huygens'principle of wave propagation.The model is designed to simulate fire behavior in grasslands with complex terrain,enabling detailed representation of fire front dynamics.By analytically solving flame plume equations,the model quantifies the combustion heat production and its impact on surrounding wind fields through buoyant lifting effects.This innovative two-way coupling of atmosphere-fire interactions enhances the model's ability to simulate fire behavior under various environmental conditions.The model incorporates multiple factors,such as the wind speed,terrain,flame plume entrainment,fuel moisture content,packing ratio,and effective flame width,overcoming the limitations of traditional models in accurately capturing the shape of fire fronts.Validation through numerical simulations demonstrates that the model effectively reproduces both the temporal and spatial evolution of fire fronts across different wind and terrain conditions.In benchmark tests with a 100-meter ignition line,the model shows remarkable agreement with fully-coupled dynamic simulations,with a mere-10.38%deviation in fire spread rate while accurately replicating fire front patterns.The proposed model offers high computational efficiency and can serve as a valuable tool for wildfire risk assessment and emergency response.
基金The authors wish to thank the financial support of the National Nat-ural Science Foundation of China,No.52038009.
文摘Fires in the railway trains are prone to cause large numbers of casualties,serious economic losses,and huge negative social impacts.The railway train carriage is a special confined built environment,where the pyrolysis,combustion,and fire spread process are different from those fire accidents in open space.Identifying the fire characteristics of the railway train carriages is the key issue to determine the fire prevention and control strategy.Therefore,this paper attempts to assess and identify the characteristics of pyrolysis,combustion,and fire spread of railway trains based on the exising research.This review documents the pyrolysis and combustion characteristics of single train material and the combustible module,summarizes the heat release rate(HRR)calculation methods and the HRR profile for different types of trains,as well as introduces the research progress in the flame spread and flashover.The main gaps and issues to be solved in terms of the effects of train speed,altitudes,and application of new energy trains are further discussed.
文摘Old towns like Lijiang have enormous historic, artistic, and architectural value. The buildings in such old towns are usually made of highly combustible materials, such as wood and grass. If a fire breaks out, it will spread to multiple buildings, so fire spreading and controlling in old towns need to be studied. This paper presents a fire spread model for old towns based on cellular automaton. The cellular automaton rules were set according to historical fire data in empirical formulas. The model also considered the effects of cli- mate. The simulation results were visualized in a geography information system. An example of a fire spread in Lijiang was investigated with the results showing that this model provides a realistic tool for predicting fire spread in old towns. Fire brigades can use this tool to predict when and how a fire spreads to minimize the losses.
文摘This paper relates to the semi-empirical model based on fire field energy balance and the physical model based on land temperature, aiming to provide a practical way of describing fire spread. Fire spread is determined by the characteristics of combustible materials and the agency of meteorological factors and terrains. Combustible materials, such as surface area, have no featured scale, yet the process of forest fire spread contains the self-replicating feature, both of which contribute to the self-similarity of fire spread. Consequently, fire behavior can be described by fractal geometry. In this research, we select Wuchagou forest in Da Hinggan Mountains as the experimental site where a forest fire took place three years ago. The forest fire was detected on low-resolution NOAA-AVHRR images, and fire spread was simulated on high-resolution TM images as another attempt to merge information. Based on remote sensing and GIS, we adopted the method of limited spreading lumping (DLA) to describe growing phenomenon to simulate the dynamic process of fire spread and adjusting shape of the result of fire simulation by the scale rule. As a result, the simulated fire and the actual fire manifest the self-similarity in their spreading shapes as well as the quantitative similarity in their areas.
基金supported by National Basic Research Program of China (2012CB719702)
文摘Since serious fire occurred frequently in recent years, fire safety of high-rise building has attracted extensive attention. A National Basic Research Program （973 program） of China has been set up by Ministry of Science and Technology （MOST） of China in 2012 to meet the research requirements of fire safety in high-rise buildings. This paper reviews the current state of art of research on fire dynamics of high-rise buildings, including the up-to-date progress of this project. The following three subjects on fire dynamics of high-rise buildings are addressed in this review： the ejected flame and fire plume behavior over facade out of the compartment window, the flame spread behavior over facade thermal insulation materiMs, and the buoyancy-driven smoke transportation characteristics along long vertical channels in high-rise buildings. Prospective future works are discussed and summarized.
文摘Eruptive fires are one of the main causes of human losses in forest fire fighting. The sudden change in fire behaviour due to a fire eruption is extremely dangerous for fire-fighters because it is unpredictable. Very little literature is available to support either modelling or occurrence prediction for this phenomenon. In this study, an unsteady physical model of fire spread is detailed, which describes the initiation and development of eruptive fires with an induced wind sub-model. The latter phenomenon is proposed as the mainspring of fire eruptions. Induced wind is proportional to the rate of spread and the rate of spread is in a non-linear relationship with induced wind. This feedback can converge or diverge depending on the conditions. The model allows both explaining why an eruption can occur and predicting explicitly its occurrence according to meteorological conditions, topographic parameters, fuel bed properties and fire front width. The model is tested by comparing its results to a set of experiments carried out at laboratory scale and during an outdoor wildfire, the Kornati accident.
文摘The first aim of this work is to provide an analytical expression to calculate the rate of spread of surface fires under no wind and no slope conditions. A previous simplified model was improved for this particular case of fire propagation. The test of this proposed model was performed by using two complete sets of experimental results with several fuel beds and variable parameters such as moisture content or bulk density. The second aim of this article is to highlight two conditions that allow stopping a fire： the low leaf area and the high value of the moisture content.
文摘Fire is one of the extreme loading events that a building may experience during its service life and can have severe consequences on the safety of its occupants,first responders,and the structure.Steel framed buildings under severe fires can experience high levels of instability at a local or global level,which in turn can lead to the partial or progressive collapse of the structure.However,in current practice,fire resistance of structures is obtained without due consideration to a number of critical factors,and this is mainly due to the high level of complexity in undertaking advanced analysis of structures under fire exposure.This paper presents a parametric study on a ten-story braced steel framed building subjected to fire exposure wherein six different parameters are evaluated:fire severity,fire spread,load paths,temperature-induced creep,local instability,and analysis regime.Results from validated finite element models are utilized to evaluate the influence of the different parameters and recommend critical parameters to be incorporated in the analysis.Results show that the susceptibility of fire-induced progressive collapse significantly depends on the severity of the fire exposure scenario,including fire intensity,fire spread,and extent of burning.Also,accounting for the full effects of transient creep in fire-induced progressive collapse analysis is needed to obtain conservative failure times under severe to very intense fire exposure.Additionally,results from the parametric study infer that the sectional classification of a steel section based on local instability can alter under fire exposure and this effect is more critical in steel columns located in the higher stories of the building;a nonslender column at ambient conditions can transform to a slender section at elevated temperatures.This can induce temperature-induced local instability in the column and lead to an early onset of instability at member and structural levels.
