短脉冲激光作用下金属材料中的热波效应计算分析

Numerical Calculation of Thermal Wave Effect in Metallic Materials Heated from Short-Pulse Laser

用一维模型,计算了脉宽为5ns、5ps两种情形的脉冲激光作用下铝和不锈钢靶材中的强瞬态热传导问题。对每种情况,分别基于经典傅立叶热传导理论和非傅立叶热波理论来计算温度场的分布及变化,并将得到的数值结果进行比较。发现当激光脉宽为ns量级时,经典傅立叶热传导和非傅立叶热波两种理论所得的结果基本一致,热波效应可以忽略;当激光脉宽为ps量级时,非傅立叶理论计算结果与傅立叶热传导的结果分离,显示出明显的热波效应。

The instantaneous thermal conduction in an aluminum sample and a stainless steel sample irradiated by 5 ns and 5 ps high-intensity laser pulses is numerically calculated in one-dimensional case. Based on the Fourierian law and the non-Fourierian thermal wave theory respectively, the distribution and evolvement of the temperature field are obtained. By comparing the resuits, it is found that when the pulse duration is 5 ns, the Fourierian law and the Non-Fourierian thermal wave theory give nearly the same temperature distributions, which implies thermal wave effect can be neglected, whereas when the pulse duration is 5 ps, different temperature patterns are gained from the non-Fourierian thermal conduction and the Fourierian thermal conduction models, which exhibits remarkable thermal wave effect.