摘要
高温烟气颗粒、二氧化碳和水蒸气是烃类池火中火焰热辐射的主要来源,而点源模型、Shokri Beyler模型和Mudan模型是计算池火辐射最常用的方法。采用这3种模型计算了直径为2 m的乙醇池火的火焰特性,得出了目标位置接受辐射强度和与池火中心距离之间的关系。根据乙醇池火试验的光谱辐射强度,以及通过简化处理计算得到的火焰周围大气环境的衰减系数,采用辐射传热理论计算目标位置处的辐射强度。将不同模型的计算结果与基于试验数据的计算结果对比发现:当热辐射强度小于1.5 k W/m2时,点源模型计算结果比较准确;当热辐射强度大于4.5 k W/m2时,Shokri Beyler模型的计算结果比较合理。在工业火灾的实际应用中,计算辐射对人员的伤害可选用点源模型与Mudan模型;计算辐射对周围建筑物的破坏可选用Shokri Beyler模型。
The work is to introduce an innovated practical analysis model for calculating the pool fire radiation intensity. As a matter of fact, pool fire is generally considered to be a common form of accidents at a storage tank space of the flammable liquid characterized by the long endurance and great liability to result in various disasters. Since the mechanism of pool fire induction can be both various and complicated, it is difficult to describe the process enough accurately and comprehensively just in resorting to one or two physical models for its origin, propagation and disaster-causing. However, what we believe it necessary to apply to is the following three important char- acteristic parameters for pool fires, that is, the burning rate of the combustible material, the flaming height and the thermal radiation in- tensity, for the said three parameters may account for the basic evalu- ation factors of the actual pool fire hazards. And, in answering to the evaluation or calculation needs of such pool fire disasters, it is neces- sary to apply the Point model, Shokri Beyler model and Mudan model to work out the radiation intensity of the hydrocarbon liquid pool fire or fires. First of all, the point model is in a position to take the flame as a point that can be regarded as a hot radiation source. And, then, such fires can also be treated as a cylindrical gray body in Shokri Beyler model and Mudan model. In so doing, we can work out the buming parameters of 2 m ethanol pool fire via the said three models. Since the relation between the radiation intensity of the target and the distance from the target position to the pool fire axis can be deduced by using empirical models, the results of the spectral radiation intensity in the ethanol pool fire experimental examples can be worked out through further calculations. What is more, as the radiant energy mainly comes from the hot smoke particles, the actual volume of the carbon dioxide and the water vapor can also be found in accord with the experimental data. Thus, consequently, the spectral attenuation coefficient of the atmosphere can also be determined by simplifying the composition while taking into account the influence of carbon dioxide and water vapor in the atmosphere. Last of all, the process of radiative thermal transfer of the flame in the atmospheric environment can be deduced by Beer Law and Lambert Law. At this step, conclu- sions can be drawn as follows： Comparing the calculation results of different models with those based on the experimental data, it can be found that, on the condition that the thermal radiation intensity is lower （less than 1.5 kW/m2）, the calculations of the point source model can be more accurate and reliable. However, if the thermal radiation intensity is higher （greater than 4.5 kW/m2） , the results of Shokri Beyler model that is gained from the calculation can be made more reasonable. Hence, the calculation errors of Mudan model and the experimental results can be made relatively stable, and, fur- thermore, the basically credible calculation results can be made clean and clear between the Shokri Beyler model and the point source model. So, we do believe that the point source model and Mudan model can both be applicable for analyzing the personal injury cases at high temperature, and, consequently, the Sbokri Beyler Model can also be used to study the thermal response of the combustion of the adjacent fire or fires.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2014年第6期76-79,共4页
Journal of Safety and Environment
基金
国家自然科学基金项目(91130028)
