基于流光-先导雷击模型对建筑物吸引半径的计算

Calculation of Attractive Radius of a Building Under Streamer-Leader Model

从先导始发的物理过程入手,建立了流注-先导模型。该模型考虑了流注茎(stem)近似圆锥体的形状特征和空间电荷屏蔽影响的二次电晕起始条件。应用上述模型,对在不同的雷电流幅值和不同高度情况下的建筑物的吸引半径进行了计算,根据计算结果拟合出了吸引半径与建筑物高度和雷电流幅值的关系表达式,并将由本文模型计算得到的建筑物等效半径与自持传输(SLIM)等其他模型的计算结果进行了对比。同时,考虑了环境因素(压强、空气湿度以及温度)对建筑物拐角等尖端处吸引半径的影响。结果表明:1)建筑物较低时,本文得到的等效半径与SLIM的计算结果具有较好的一致性;建筑物较高时,对应两者等效半径的计算结果存在差异,但均大于基于电气几何模型的计算结果。2)压强和空气湿度对建筑物吸引半径有一定的影响,而温度对其的影响并不显著。

Starting with the physical process of leader inception,a streamer-leader model considering cone-shape stem and the shielding effect of space charges is established,which is suitable for analyzing the evaluation of upward connecting leader inception from a grounded structure.Based on this model,attractive radius in several conditions of different current and different structure height have been calculated.The relationship among attractive radius,current and structure height are fitted according to the results.And we have compared the calculation results in the equivalent radius of the complex grounded structures based on our model with SLIM and others.At the same time,the influence of environmental factors(the temperature,the atmospheric pressure and the absolute humidity of air)on attractive radius of the corner of grounded structures has been considered in the paper.The results have been found:1)The equivalent radius based our model are is very close to SLIM with lower structure height,the equivalent radius still exist differences with higher structure height,but both of the results are greater than EGM.2)Atmospheric pressure and the absolute humidity of air have certain impact on attract radius,however,the influence of the temperature is not significant.