激光与空气作用过程中辐射能量损失的研究

Study of radiation energy loss in laser-air interaction

关键词:  辐射流体力学  辐射能量损失  光线追踪法  能量沉积

Key words:  Radiation hydrodynamics  Radiation loss  Ray tracking method  Energy deposition

摘要:

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。

Abstract:

The process in laser-air interaction is related to radiation.The effect of high-temperature air radiation on air fluid mechanical process is investigated.It is found that the radiation energy density and pressure can be ignored,while the radiation energy loss cannot be neglected.Ray tracing method is used to compute the absorbed energy by the radiation transfer equation.According to the optical depth of the grid,radiation loss is determined.Control equations containing energy source term is solved numerically,and evolvement of the laser-induced plasma field is simulated.The functional relationship between radiation loss and input laser energy has been obtained.