| In recent years,world cultural heritage sites have been damaged by fire,and the fires in shouli city,Okinawa,and Notre Dame cathedral,Paris,have sounded the alarm.How to effectively reduce the occurrence of fire,need to take preventive protection methods,before the fire through technical or management means,to eliminate the potential danger of fire and flame spread conditions.At present,there are few literatures on the research on the flame spread of ancient buildings,and the existing literatures are not comprehensive enough to consider the simulation of the flame spread of ancient buildings,so that the specific change process of the flame spread cannot be effectively reflected.Therefore,it is necessary to deeply explore the dynamic change law of flame spreading in ancient buildings.This paper adopts the methods of literature research,field investigation and fire simulation.Based on the existing research literature and field research,accurate data were obtained,the construction characteristics of ancient buildings were analyzed,and the statistical measurement of information of ancient buildings,the identification of timber properties of ancient buildings and the preliminary calculation of fire load were completed.BIM technology is adopted to carry out parametric modeling of ancient buildings,realize the sharing of building information model,and put forward a new application of parametric modeling of ancient buildings.At the same time,Pyrosim was used to reasonably set the fire scene and complete the simulation,to explore the flame spread of ancient buildings under the influence of different factors,and to make the longitudinal and transverse flame spread dynamic change curve.The fire spreading mechanism of ancient buildings under the influence of wind speed and roof was systematically analyzed,the impact of wind speed and roof on ancient buildings was explored,and the critical temperature value of the roof was given.It makes up for the research on the dynamic change trend of flame spreading in ancient buildings.The results show that: in the whole building space,the combustion of the combustion source generates heat,and the fire spreads along the wall to the roof due to the action of thermal buoyancy.In the whole process of flame spreading,the upper temperature is much higher than the lower temperature,and the transverse flame spreading rate is faster.Windspeed and roof are two important influencing factors.Wind speed will accelerate the rate of flame spread and the time to reach the boom.Roof will hinder the direction of flame spread and restrict the spread of flame to other rooms.When the explosion occurs,the temperature of the upper part of the building is T=530℃--570℃.The content of this paper provides quantitative reference basis for the research on the change law and influencing factors of ancient buildings’ flame spread,and provides reliable theoretical support for the control of ancient buildings’ flame spread. |
