自适应FGM激光熔覆成形的粉体快速混合机理

多相粉体的快速、精确混合是自适应功能梯度材料(A-FGM)零件的成形基础.为提高载气驱动下的粉体混合均匀性，建立了气固两相流数值分析模型，采用雷诺时均法进行数值模拟，设计了一种载气驱动的快速混粉设备，通过ANSYS-FLUENT分析了不同混粉参数和混粉器构型对混粉腔体内流场的影响规律，并通过元素分析和图像处理实验测量了粉末混合的均匀度.实验结果表明:载气驱动下的合金粉体混合机制以对流混合为主，提高粉粒的平均流速和位移能有效增加粉粒群的流动性，提高粉体混合均匀度.

Powder Mixing Mechanism of Laser Cladding Forming for Adaptive FGM

Fast and accurate mixing of multiphase powder is the foundation of forming parts from adaptive functional graded materials(A-FGM). In order to improve the powder mixing homogeneity driven by gas， a numerical analysis model of gas-solid two-phase flow was established. The Reynolds time average method was used for numerical simulation. A kind of powder mixing equipment driven by carrier gas was designed. A finite element method based on ANSYS-FLUENT was used to analyze the effect of mixing parameters and configurations on the flow field in the powder mixer. The experiment for testing mixing homogeneity based on elemental analysis and image processing was designed. The results show that the gas-dynamic mixing mechanism of the alloy powders is mainly in convective mix. As the average velocity and displacement of the powders increase， the powder flowability can be improved to increase the mixing homogeneity.