脉冲Nd：YAG激光表面熔凝流场与热场的数值模拟  

Numerical Simulation of Transient Fluid Flow and Temperature FieldDuring Pulsed Nd: YAG Laser Surface Remelting

作　　者：雷永平[1] 史耀武[1] 周家瑾 

机构地区：[1]西安交通大学机械工程学院

出　　处：《中国激光》1996年第4期369-375,共7页Chinese Journal of Lasers

基　　金：国家重点科技项目(攻关);(85-725-O1-09-03)资助

摘　　要：以合金相交多区域统一模型为基础，利用数值模拟方法，对脉冲Ｎｄ：ＹＡＧ激光表面熔凝过程的非稳态温度场和熔区内的流场进行了理论分析。能量方程求解中考虑了固液相变潜热的吸收与释放；合金元素气化热损失、自然对流与辐射热损失；动量方程求解中考虑了热表面张力与浮力联合驱动流。结合实验条件计算了１Ｃｒ１８Ｎｉ９Ｔｉ不锈钢在低频脉冲熔凝情况下熔区的形状和尺寸，并与实验解剖进行了比较。结果表明，在占空比较小时，系列脉冲中每一脉冲形成的表面熔区形状和尺寸可用定点轴对称脉冲模型很好地近似。Based on one region continuum model for alloy phase transformation, thetransient fluid flow and temperature fields for pulsed Nd: YAG laser surface remelting havebeen calculated by using numerical simulation method. The absorption (melting process)and release(solidifying process)of latent heat, the heat loss by alloy elements vaporization,radiation,and natural convection are included in the solving conditions of the energyequation.The thermocapillary and buoyancy driven flow are included in the solution ofmomentum equations.According to the experimental condition, the melted region shapesand sizes are calculated for 1Cr18Ni9Ti stainless steel in pulsed Nd: YAG laser surfaceremelting of lower frequency and a shot pulse duration. It is revealed that a tow dimensional axisymmetric model can properly simulate the transient fluid flow in the meltedregion and the melted region shapes for either individual pulse or a series of pulsedoverlapping remelting regions.

关 键 词：YAG激光 数值模拟 流场 温度 激光熔凝 

分 类 号：TG155.25[金属学及工艺—热处理] TN248[金属学及工艺—金属学]