薄层物料受激光脉冲热作用的数值模拟

NUMERICAL SIMULATION OF NON-FOURIER HEAT CONDUCTION IN THIN LAYER POROUS MATERIAL HEATED BY MICROSECOND LASER PULSE OF HIGH POWER DENSITY

有别于传统的将加热光源作为第二类边界条件的传热计算方法 ,考虑到激光与薄层多孔材料热相互作用 ,将激光加热处理为在被加热物料内沿光程按指数规律衰减的内加热源 .考虑到薄层多孔材料在大功率微秒脉冲激光作用下可能会出现极为明显的非傅立叶效应 ,采用非傅立叶导热的双曲型模型描述多孔材料内的传热过程 ,并用有限差分方法对其进行数值求解 。

In the traditional heat transfer computation,laser heating is always treated as one kind of special boundary conditions,that is, the second boundary condition,which is not fit for the real condition of laser absorption,especially for the thin layer porous material.Differently from the traditional methods,the laser heating is regarded as an inner thermal source and it is assumed that the intensity of the laser attenuates exponentially with its penetration depth.Since evident non Fourier heat conduction effects may appear in thin layer porous materials heated by the high intensity laser pulse,the hyperbolic non Fourier heat conduction model is used to describe this heat transfer case and the corresponding numerical solution is obtained with the finite difference method.According to the obtained solution,some correlations of the non Fourier effect and the optical property of the heated materials are obtained too. [