Powder flow can affect the temperature variations in directed energy deposition (DED). However, the direct coupling mechanism remains unknown. To solve this problem, the heat and mass transfer in additive manufacturing was simulated using dynamic coupling. The interactions between the multiphase flow and heat transfer were established. A comparison with experiment shows that the accuracy of the predictions of the numerical simulation regarding powder size distributions and temperature increases is higher than 95 %. The average temperature increase of the metal powders with different weight functions was highly consistent in the simulation process. As the powder size increases, the average temperature of the powder on the printing plane decreases. This was the reason for the formation of a deeper melt pool in the case of smaller particles in the experiment. The different curvatures between the particle surface and melt pool surface lead to a decreased energy absorption efficiency in DED. The relationship between the powder features and the melt pool size was studied. A decrease in the powder flow rate increased the temperature, leading to a larger melt depth.

中文翻译：

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定向能量沉积中的气体-粒子-热动态耦合模拟


粉末流动会影响定向能量沉积 (DED) 中的温度变化。然而，直接耦合机制仍然未知。为了解决这个问题，使用动态耦合模拟增材制造中的传热和传质。建立了多相流和传热之间的相互作用。与实验对比表明，数值模拟对粉末粒度分布和温度升高的预测准确度高于95%。不同重量函数的金属粉末的平均温升在模拟过程中高度一致。随着粉末尺寸的增加，打印平面上粉末的平均温度降低。这就是实验中颗粒较小的情况下形成更深熔池的原因。颗粒表面和熔池表面之间的不同曲率导致DED能量吸收效率降低。研究了粉末特性与熔池尺寸之间的关系。粉末流量的降低导致温度升高，导致熔体深度增大。