Indoor-outdoor Emergency Evacuation Model Based Fire Scene Simulation

Fire is one of the major disasters that endanger public safety and threaten the survival and development of humans.Due to the internal characteristic of high personnel density and complex structure of large modern buildings which are brought about by the rapid economic development,there are many potential fire hazards.Studying how to establish safe and proper emergency evacuation routes for large-scale indoor-outdoor fire scenes has important significance and reference value for emergency rescue,evacuation command,and fire evacuation manoeuvre.In order to solve the existing problems about the current emergency evacuation,this paper conducts research on fire scene simulation and indoor-outdoor evacuation models which are based on GIS technology,three-dimensional modeling technology,fire numerical simulation technology and path searching technology.The main achievements and conclusions are as follow:(1)A three dimensional modeling method for fire environment is proposed to study indoor-outdoor fire environment model by using GIS indoor-outdoor mapping and three-dimensional modeling technology.Firstly,the two dimensional indoor and outdoor maps are made by the distribution data of indoor and outdoor objects.Then,according to the two dimensional indoor and outdoor map,the three dimensional fire environmental models are respectively established by using the three dimensional modeling method.(2)Study the fire scene numerical simulation model by using fire numerical simulation technology.Based on the principle of fire numerical simulation technology,the temperature variation and the visibility of smoke and other parameters in the fire combustion process are calculated by solving the Navier-Stokes equations.A subregional variable-scale meshing method is proposed to improve the efficiency of the fire numerical calculation for the complex structure of a community because computation on numerous grids is costly in terms of time.Subregional variable-scale meshing can improve simulation efficiency while maintaining the level of simulated accuracy.By analyzing the fire scene simulation results can evaluate the impact of fire hazard on the evacuation path selection.(3)Establish the indoor-outdoor evacuation route searching models based on A* path searching algorithm and Dijkstra path searching algorithm respectively.By using social force model to improve the heuristic function of the A* path search searching algorithm.The path selection is weighted with various physical forces.It is used to represent the interaction between humans and humans with the environment in the evacuation process.Changing the rules for selection of indoor evacuation routes to improve the evacuation routes to become safer under the influence of fire.The rules for routes selection are established by analyzing the fire hazard distribution.Based on the GIS road network models,the Dijkstra path searching algorithm is used to calculate the shortest outdoor evacuation path.(4)The conversion process between grid and network data connects the indoor to outdoor emergency evacuation routes for fire escape.Based on the proposed methods and models,we select a representative large scale building as the research object,establish indoor-outdoor three dimensional fire scene simulation models,and respectively study the indoor evacuation routes and outdoor evacuation routes under the influence of fire.By connecting indoor to outdoor path through conversion process,an integrated indoor-outdoor emergency evacuation model is established.