雷击时金属油罐的损伤与温升特性

Ablation Damage and Temperature Rise of Metal Oil Tanks Struck by Direct Lightning

雷击时金属油罐的损伤和温升特性是油罐防雷保护研究的关键基础之一。为此,采用模拟雷电流试验方法研究了金属油罐常用材料钢Q235B和铝3003的雷击损伤与温升特性,分析了不同雷电流分量、电流幅值、转移电荷量和作用积分对金属损伤和温升特性的影响。结果表明:不同雷电流分量冲击下金属的损伤特征差异明显;金属损伤面积主要取决于雷电流幅值,损伤深度主要取决于转移电荷量,雷电流的作用积分与雷击损伤的相关性较小;雷击造成的金属温升与转移电荷量近似成线性关系,回击后长持续时间雷电流分量造成的温升最高,幅值400 A的长持续时间雷电流分量作用下,厚度5 mm的钢Q235B金属板背面温升可达330℃,铝3003金属板的背面温升可达500℃,接近油气自燃点;相同转移电荷量的首次短时间回击电流和回击间长持续时间雷电流分量造成的温升相接近,后续短持续时间回击电流分量造成的温升可忽略。

Research on ablation damage and temperature rise of the metal oil tanks struck by direct lightning is the basis for lightning protection of metal oil tanks. We experimentally researched the ablation damage and temperature rise of metal oil tank＇s common materials steel alloy Q235 B and aluminum alloy 3003 caused by direct lightning. Moreover, we analyzed the effects of different components of lightning currents, charge transfer, and action integral on the metal ablation and temperature rise. The results show that the metal ablation damage and temperature rise are distinctly different with the different components of lightning currents. The ablation depth is closely related to charge transfer and the ablation area is closely related to lightning current amplitude. The action integral is meaningless for metal ablation analysis. The temperature rise almost linearly increases with charge transfer. The temperature rise caused by long continuing current is much higher than that caused by other components of lightning currents. The temperature rise caused by long continuing current, whose amplitude is 400 A, can reach 330 ℃ for steel alloy Q235 B and 500 ℃ for aluminum alloy 3003 with its thickness 5 mm, which approach the self-ignition temperatures of oil-gas mixture. For constant charge transfer, the temperature rise caused by first stroke is almost as high as continuing current of interval stroke. The temperature rise caused by subsequent stroke can be neglected.