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
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
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.
