中文摘要：

翁丁村是我国典型的杆栏式古建筑群,为防止火灾在建筑间蔓延,当地传统风俗中形成了在发生火灾时拆除建筑茅草顶的防火技法。为验证这种防火技法的有效性并为后期试验提供理论依据,采用火灾动力学模拟软件FDS对典型民居进行了火灾动力学分析,获得了不同屋顶拆除时间火灾场景下的火灾热释放速率、热辐射通量和建筑间安全距离。在此基础上,结合理论分析给出了拆除屋顶的临界时间的理论计算公式,并比较了两种不同热辐射简化计算模型的计算效果。结果表明：在临界时间之前,即建筑火灾由燃料控制型转变为通风控制型之前拆除屋顶,可有效降低火灾发生时的热释放速率和热辐射强度,从而能有效地防止建筑间的火灾蔓延;由于房屋间距小,在临界时间之后才拆除起火建筑的屋顶,会导致火灾在建筑间蔓延;采用面源简化计算模型计算不同距离的热辐射通量,与计算机模拟的结果更为接近。

英文摘要：

Wengding village is a typical railing style ancient building group in China. Local customs have formed a protection method to prevent fire spreading from building to building by removing thatched roof. In order to verify the validity of this fire protection technique and provide a theoretical basis for the later test, fire scenarios which re- move roof at different times were simulated by using the fire dynamic simulation software. The heat release rate, heat radiation flux and safe distance between houses were obtained for fire scenarios with different roof removing times. In addition, a theoretical calculation formula about critical time of removing roof was provided through theo- retical analysis. The calculation effects of two different kinds of heat radiation simplified calculation model were compared. The results showed that, before critical time, that is, the fire shift from the fuel controlled pattern to ventilation controlled pattern, roof removal could effectively reduce the heat release rate and the heat radiation flux, so that fire between buildings could be effectively prevented from spreading. Due to the short distance between hou- ses, removing the thatched roof after the critical time could lead fire to spread between houses. At different dis- tances, the heat radiation flux calculated by the area source simplified calculation model was close to the computer simulation results.