Two-dimensional heat transfer and melt flow in the laser-affected zone at selective laser melting of thin walls

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2025-09-12 DOI:10.1016/j.ijthermalsci.2025.110253

Andrey V. Gusarov, Roman S. Khmyrov, Tatiana V. Tarasova, Sergey N. Grigoriev

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Abstract

Selective laser melting (SLM) is employed for obtaining thin-wall elements including lightweight lattice structures. The so-called single-track walls can be considered as thermally thin in the scale of the laser-affected zone. Thus, heat and mass transfer in such a zone become essentially two-dimensional. An original setup is developed for high-speed imaging of the laser-affected zone. Melt pool dimensions are measured as function of process parameters in 170 μm-thick plates of Sn60Pb40 alloy. A computational fluid dynamics (CFD) model of two-dimensional conductive heat transfer and thermocapillary-driven convection is developed. The conservation laws for mass, momentum, and energy are numerically solved by a second-order Godunov finite-volume method using an original Riemann solver developed for the applied equation of state. The CFD model is validated by comparison with the experiments. Laser processing is numerically simulated for thin walls of AlSi10Mg and Sn60Pb40 alloys and Fe. Formation of two outward vortices in the melt pool is revealed. Surface-active impurities can make the surface tension-temperature function non-monotonous giving raise additional vortices with the opposite inward flow direction. The influence of melt convection on the melt pool size is not considerable in the conditions of selective laser melting (SLM). The flow velocity in the melt pool is around or less than the laser scanning speed. This means insufficient mixing in the melt pool. The correlation between the error of the Rosenthal model and the latent heat of fusion is carefully studied resulting an analytical model for estimating the melt pool depth. In the studied SLM cases, the accuracy of the developed analytical model is within 10 % relative the CFD model. The obtained experimental and theoretical results indicate that the melt depth is approximately proportional to linear energy density LED in the typical conditions of SLM. This can be useful when optimizing the SLM process.

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薄壁选择性激光熔化激光影响区的二维传热和熔体流动

采用选择性激光熔化（SLM）技术获得了包含轻质点阵结构的薄壁元件。在激光影响区范围内，所谓的单轨壁可以被认为是热薄的。因此，在这样一个区域内的传热和传质基本上变成了二维的。开发了一种用于激光影响区的高速成像的原始装置。在170 μm厚的Sn60Pb40合金板上测量了熔池尺寸随工艺参数的变化规律。建立了二维导热传热和热毛细管驱动对流的计算流体力学模型。质量、动量和能量守恒定律采用二阶Godunov有限体积法，采用应用状态方程的原始黎曼解算器进行数值求解。通过与实验的对比，验证了CFD模型的正确性。对AlSi10Mg、Sn60Pb40合金和Fe薄壁的激光加工进行了数值模拟。揭示了熔池中两个向外漩涡的形成。表面活性杂质可以使表面张力-温度函数不单调，产生与向内流动方向相反的附加涡。在选择性激光熔化（SLM）条件下，熔体对流对熔池尺寸的影响不大。熔池内的流动速度接近或小于激光扫描速度。这意味着熔池中的混合不足。仔细研究了罗森塔尔模型误差与熔合潜热之间的关系，得到了一个估算熔池深度的解析模型。在所研究的SLM案例中，所建立的分析模型相对于CFD模型的精度在10%以内。实验和理论结果表明，在典型的SLM条件下，熔体深度与线性能量密度近似成正比。这在优化SLM过程时非常有用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.