Spattering and denudation in laser powder bed fusion process: Multiphase flow modelling
Spattering and denudation in laser powder bed fusion process: Multiphase flow modelling
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DOI：
10.1016/j.actamat.2020.06.033
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发表时间：
2020-09-01
期刊：
影响因子：
9.4
通讯作者：
Yan, Wentao
中科院分区：
文献类型：
--
作者：
Chen, Hui;Yan, Wentao
为了了解激光粉床熔化过程中飞溅和剥蚀现象的物理机制，我们建立了一个离散单元法和有限体积法双向耦合的多相流模型，其中考虑了粉末颗粒和气体之间的动量和能量交换。这是首次在计算模型中再现了气相和粉末颗粒在溅射和剥落过程中的动力学行为，与已发表的实验观测结果吻合较好。金属蒸气沿喷射方向喷出并急剧减速，同时径向膨胀，导致环境气体产生显著的涡流。模拟结果表明，在溅射和剥蚀过程中，水蒸气喷流和旋涡流动占主导地位，热浮力效应可以忽略不计。此外，还考察了喷射角的影响：在60度-120度范围内效果不明显，大于150度则消除堆积带，形成完全裸露的剥蚀带。(C)2020 Acta Materialia Inc.由爱思唯尔有限公司出版。版权所有。
To understand the physical mechanisms of the spattering and denudation phenomena in the laser powder bed fusion process, we develop a multiphase flow model by bi-directionally coupling the discrete element method and finite volume method, where the exchanges of both momentum and energy between the powder particles and gases are incorporated. It is the first time that the dynamic behaviours of both the gas phase and powder particles during the spattering and denudation phenomena are reproduced in computational modelling, which agree well with the published experimental observation. The metal vapour spouts out and decelerates sharply along the jetting direction while expanding radially, which induces remarkable vortex flows of the ambient gas. With comparative simulation cases, the vapour jetting and the consequent vortex flow are demonstrated to be dominant in the spattering and denudation phenomena, and the thermal buoyancy effect is proved to be negligible. Moreover, the influence of the jetting angle is investigated: no remarkable effect within the range of 60 degrees - 120 degrees; while larger than 150 degrees, the accumulation zone is eliminated leading to a completely exposed denudation zone. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.