激光熔覆熔池二维准稳态流场及温度场的数值模拟

A NUMERICAL SIMULATION FOR TWO DIMENSIONAL QUASI-STATE FLUID FLOW FIELD AND TEMPERATURE FIELD IN THE MOLTEN POOL OF LASER CLADDING

本文建立了二维准稳态激光熔覆熔池流场及温度场的数值模型，除考虑对流换热外，模型还考虑了局部大变形自由表面．在贴体正交曲线坐标系下采用了非交错网格SIMPLE算法离散求解动量方程，计算出了激光熔覆熔池自由表面形状和温度场、速度场及局部特征凝团参.数值结果表明，表面张力温度系数和扫描速度μ0对熔池自由表面形状及熔池内温度分布、速度分布有重要影响．同时进行激光熔覆的工艺实验，实测枝晶二次臂间距（SDAD）的实验结果和数值结果吻合良好．

A two dimensional quasi-state numerical model of fluid flow and heat transfer processin the melted pool of laser cladding was developed, taking into account deformation of free surface, inaddition to the heat transfer and fluid flow in the molten pool. Momentum equation is discreted andsolved by using SIMPLE algorithm, combined with momentum interpolation technology and body-fittedorthogonal curvilinear coordinates. The shape of free surface, temperature field, fluid flow field and localizedcharacteristic solidification parameters in the laser cladding pool are calculated successfUlly. Numericalresults show that surface tension temperature coefficient and scanning speed no have an importanteffect on the shape of free surface, localized characteristic solidification parameters, temperature distributionand velocity distribution. The experiment of laser cladding was done, and values of the secondary dendritearm distance (SDAD) calculated are agreement with those obtained experimentally.