针对送粉式激光熔覆的特点，基于生死单元法建立了一种可以同时计算瞬态温度场及熔覆层几何形貌的三维数值模型，模型中考虑了送粉过程中激光能量的衰减和粉末颗粒的温升。基于该模型对送粉式激光熔覆过程中的温度场分布和几何形貌特点进行了分析。结果表明，在熔覆开始较短时间后，工件的瞬态温度分布与熔覆层几何形貌基本保持稳定。进行了不同送粉速率下的送粉式激光熔覆试验，对比了熔覆层横截面几何形貌的试验结果和计算结果，熔覆层表面轮廓线与试验结果基本保持一致，熔覆层的宽度、高度和熔深与试验结果基本吻合，说明了所建立的激光熔覆层几何形貌计算模型的有效性和可靠性。

A three-dimensional numerical model based on the birth-death element method is developed on the basis of characteristics of powder feeding laser cladding. The model, which takes the laser power attenuation by the powder stream and the heating of powder particles in the powder feeding process into account, has the capability of predicting the transient thermal field and coating geometry. Temperature distribution and geometric characteristic of coating during laser cladding process are investigated. The results show that the temperature field and coating geometry keep stable after a short initial stage of the process. Experiments with different powder feeding rates are performed to validate the calculated results. The calculated coating width, height and depth, as well as outline of coating, agree with the experimental ones, so the reliability of the model is proved.