Experimental And Theoretical Study Of The Ignition Of Timber By Incandescent Lamp

With the rapid development of China’s economic construction, dramatic growth in material wealth, andthe continuous development of new energy resources, new materials, fires occur with increasing frequency, and losses caused by fire are becoming increasingly severe. Fire has become one of the most frequent disasters that endanger human life and social development. Among many types of fires, fire caused bysolid combustibles, particularly the wood is the most common and also the most closely related to human life by far. Wood is so easy to obtain and easy to processthat it has been widely used in such fields as construction and decoration. However, wood, as a combustible material, can easily develop into a large-scale fire, bringing great losses to people’s lives and property safety.In the development process of a real fire, heat radiation is often a major factor to determinethe rate of growth and development of fire process. Moreover, the processes of pyrolysis and ignition of solid combustiblesunder the effect of an external heat radiation, as the initial stages of fire development, directly affect the spread and development of post-fire. Therefore, it is very necessary to conduct in-depth research on the mechanism of thermal decomposition and ignition of solid combustibles and predict the behavior of thermal decomposition and ignition of combustible materials. Pyrolysis behaviors and ignition characteristics of solid combustibles under external heat radiation, has always been an important subject and direction in the field of fire scientific research.Under the effect of heat radiation, wood starts absorbing heat to evaporate water. When the water is completely precipitated, the wood surface and internal temperatures begin to rise over time. When the temperature reaches a certain value, pyrolysis occurs. Then a large amount of combustible pyrolysis gases escape from the wood surface andmix with the oxygen in the external environment, forming a combustible premixed gas. when the premixed combustible gases reach a critical value, the burning takes place.Based on the previous research, this paper conducts experimental study and theoretical analysis of pyrolysis, charring and ignition characteristics of wood exposed to a200W incandescent bulb, to throw light on Xinjiang "3.16" great fire. The experimental study consists of two parts:the first part is the calibration experiment to measure the effective emissivity of the incandescent bulb, and the second part is the wood ignition experiments where the incandescent light bulb is the external radiation sources. On the basis of the experimental study, three simple models are established to estimate the incident heat flux in different positions around an incandescent bulb, and the minimum heat flux to achieve ignition, and to correlate the ignition time with distance between the incandescent bulb and the wood sample. Considerable agreement between experimental and theoretical results is obtained in most cases, whichverifies the correctness of the models.