本研究使用開源軟體OpenFOAM v2206建立三維數值模型以探討鎖孔銲接中流場之流況及成型之形貌，其中考慮反衝壓力(Recoil force)、馬倫格尼力(Marangoni force)與表面張力(Surface tension)對於熔池流動的影響，以及固液化模型、多相流模型與蒸發潛熱來更貼近實際銲接過程之物理現象。多數文獻中使用面熱源或體熱源模型等形式將能量直接導入金屬基板進行銲接模擬，為符合光在金屬介質上的多重反射行為，本研究在鎖孔銲接中導入雷射反射模型，以描述材料對於雷射能量之吸收率隨鎖孔深度增加而有所變化，並分析銲接製程中鎖孔震盪行為與噴濺形成過程。
在過去銲接數值計算中，需要對應實驗工況而設置諸多模擬參數，且過程中需要實驗工況之參數進入模型中，為此蒐集多篇相關文獻之實驗加工參數，利用無因次參數及熔池成型尺寸與本研究之數值模擬配合，整理出熔池成型尺寸之預測結果。

This study utilizes OpenFOAM v2206 to establish a three-dimensional numerical model for investigating the flow patterns and morphological characteristics in welding. The study takes into account the influence of recoil force, Marangoni force, and surface tension on the molten pool flow. Additionally, solid-liquid phase change models, multiphase flow models, and latent heat of evaporation are incorporated to close the physical phenomena in actual welding processes.

Most literature employs forms such as surface heat sources or volume heat source models to directly introduce energy into the metal substrate for welding simulations. To align with the multiple reflections of laser light on the metal medium, this study introduces a laser reflection model in keyhole welding. This model describes how the material's absorption rate of laser energy changes with increasing keyhole depth. The study also analyzes keyhole oscillation behavior and the spatter formation process during the welding process.
Through the results, it was found that when the recoil force exceeds surface tension, the keyhole becomes deeper. Conversely, when surface tension is greater than the recoil force, the rate of keyhole penetration slows down. Marangoni force drives the molten pool flow, leading to keyhole collapse and the formation of pores. Due to the intense keyhole oscillation, the absorption rate also undergoes significant changes. Finally, non-dimensional parameters are used to predict molten pool dimensions, and the impact of the Fourier number on the molten pool is analyzed.

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