论文标题
表面变形对低prandtl熔池中热毛细管流量不稳定性的影响与表面活性剂
The influence of surface deformation on thermocapillary flow instabilities in low Prandtl melting pools with surfactants
论文作者
论文摘要
在材料的激光处理过程中，低PRANDTL数量熔池中的热量和流体流对规定的边界条件敏感，并且响应高度非线性。先前的研究表明，在高马龙尼数中，带有表面活性剂的熔体池中的流体流量可能不稳定。在熔融池中熔融金属流量的数值模拟中，表面变形及其对材料吸收的能量的影响通常被忽略。但是，这种简化的假设可以降低数值预测的准确性水平，并降低表面变形。在本研究中，我们进行了三维数值模拟，以实现表面变形对金属合金与表面活性剂的激光融化中热毛细管流不稳定性的影响。我们的计算模型基于有限体积方法，并利用了气体 - 金属接口跟踪的流体量（VOF）方法。此外，我们采用了动态调整的热源模型，并讨论了其对熔体池行为的数值预测的影响。我们的结果表明，数值模拟中的自由表面变形可以增强预测的流动不稳定性，从而增强了预测的固液界面形态。
Heat and fluid flow in low Prandtl number melting pools during laser processing of materials are sensitive to the prescribed boundary conditions, and the responses are highly nonlinear. Previous studies have shown that fluid flow in melt pools with surfactants can be unstable at high Marangoni numbers. In numerical simulations of molten metal flow in melt pools, surface deformations and its influence on the energy absorbed by the material are often neglected. However, this simplifying assumption may reduce the level of accuracy of numerical predictions with surface deformations. In the present study, we carry out three-dimensional numerical simulations to realise the effects of surface deformations on thermocapillary flow instabilities in laser melting of a metallic alloy with surfactants. Our computational model is based on the finite-volume method and utilises the volume-of-fluid (VOF) method for gas-metal interface tracking. Additionally, we employ a dynamically adjusted heat source model and discuss its influence on numerical predictions of the melt pool behaviour. Our results demonstrate that including free surface deformations in numerical simulations enhances the predicted flow instabilities and, thus, the predicted solid-liquid interface morphologies.
