Fire Simulation Analysis And Flashover Prediction Of Ancient Buildings With Brick And Wood Structure

Most of the ancient buildings in China are made of brick and wood.After years of exposure to the weather,the moisture content of the wood is extremely low.Even a little spark may cause flashover,causing irreparable losses to human civilization.It is necessary to take scientific and effective methods to restrain the occurrence of flashover.At present,researches on flashover mostly focus on all kinds of modern buildings,and the research process is partial to theory.There is no research on whether related types of fires can occur in reality,and researches on flashover of ancient buildings in China are even less.Therefore,it is of great scientific value and practical significance to conduct in-depth research on the flashover stage of ancient building fire.This paper mainly studies the analysis and prediction of the flashover stage of indoor fire in ancient buildings.Taking the ancient building in Xi ’an as the research object.According to the existing research literature and the data obtained from the investigation,establish a numerical model,calculate the fire load.The flashover prediction method proposed by Thomas is used to preliminarily predict the flashover of fire.Combining the comprehensive prediction method of fire flashover with the numerical simulation method of fire,the influence of fire source on flashover was studied.Based on the average heat release rate curve,ceiling temperature curve,dynamic change diagram of fire and slice temperature cloud diagram of ancient buildings,the specific scene of fire flashover is analyzed.Finally,the comprehensive prediction method of flashover is used to make further judgment on the ancient buildings.The results show that the flashover prediction method proposed by Thomas can simply predict whether the flashover phenomenon will occur when a fire occurs,but this method only considers the influence of ventilation factors,and cannot make a judgment on other scenarios.The combination of flashover comprehensive prediction method and numerical simulation method can be used to analyze and predict flashover well.In this paper,the initial temperature of flashover of ancient buildings is about 280℃,which can be used as a conventional criterion for flashover of similar ancient buildings.By increasing the area of the fire source(in the case of the same heat release rate of the fire source),reducing the heat release rate of the fire source and removing the fire source near the wall,the flashover occurrence time can be effectively delayed and even the flashover phenomenon can be inhibited.The research content of this paper provides some valuable reference basis for the study of flashover of ancient buildings.