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激光与空气相互过程中,与辐射相关的各种过程起着特别重要的作用。研究了高温气体辐射对气体流体力学过程的影响。辐射能量密度和压力对气体状态和运动的影响完全可以忽略不计,而流场的辐射能量损失不能忽略。利用光线追踪法,运用辐射输运方程,根据光线在网格中的传播路径,计算空气吸收的激光能量;根据网格厚度,确定辐射能量损失。数值求解含能量源项的流体控制方程,对激光击穿空气的等离子流场演化过程进行了模拟,得到了辐射能量损失随入射激光能量的变化规律。
During laser-air interaction, various processes related to radiation play a particularly important role. The effect of high temperature gas radiation on the gas hydromechanics process was studied. The influence of radiant energy density and pressure on gas state and movement can be neglected completely, and the loss of radiant energy in the flow field can not be neglected. The ray tracing method is used to calculate the laser energy absorbed by the air according to the propagation path of the light in the grid by using the radiation transport equation. The radiation energy loss is determined according to the grid thickness. Numerical simulation of the fluid control equation with energy source term was used to simulate the plasma flow field evolution process of laser breakdown air. The variation of radiation energy loss with incident laser energy was obtained.