1064nm激光致熔石英损伤的数值模拟研究

Numerical simulation study of fused silica damage induced by 1064nm laser

为了研究1064nm激光对增透熔石英的热应力损伤机理以及等离子体分布等效应。基于热传导和气体动力学理论,探究了毫秒激光对增透熔石英的热应力损伤和致燃损伤的理论模型,利用comsol软件模拟了1064nm激光作用增透熔石英时材料内部的热损伤、应力损伤以及激光支持燃烧波,模拟结果表明在激光光斑半径区域内,温升较为明显,形成较大的温度梯度,激光作用区域受热膨胀,其余区域会对膨胀发生抵制,因此材料内部产生应力,其中上表面的径向应力、环向应力在激光光斑边缘附近达到最大值,应力损伤应该先从辐照中心点或激光光斑边缘附近产生,同时发现等离子体的传播是稳态的,燃烧波的最大速度发生在最初时刻,并随着扩散时间逐渐变低。

The mechanism of the thermal stress damage and the distribution of plasma were studied in term of anti-reflection fused silica irradiated by 1064 nm laser. Based on the theories of thermal conduction and gas dynamics, theoretical model of ther- mal stress damage and combustion damage of anti-reflection fused silica induced by millisecond laser was analyzed. Thermal dam- age, stress damage and laser supported combustion wave of internal space of anti-reflection fused silica was simulated by COM- SOL software. The simulation results show that, roughly with in the area of laser beam spot, the temperature increased obviously with large temperature gradient. Thermal expansion of this lasing area was restricted by the other part, causing internal stress of the material, in which radial stress and circumferential stress of upside surface reached their maximum values in the edge of laser spot. Stress damage was generated in irradiation center point or the edge of laser spot, with steady propagation of plasma. Speed of combustion wave gradually decreased with time from its maximum at the initial moment.