藉數值模擬與理論分析建構氣霧法製程中粉末粒徑降複雜度之預測方法

Developing a Reduced-Complexity Prediction Method for the Powder Size of a Gas Atomization Production via Numerical Simulation and Theoretical Analysis

黃閔賢(Min-Xian Huang)

指導教授 ： 楊馥菱

國立臺灣大學/工學院/機械工程學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202004087

摘要

透過氣霧法製程生產金屬粉末是冶金工業中重要的一環，然而如何準確地控制金屬粉末的粒徑大小一直是個困難的挑戰，此論文希望透過數值模擬以及理論分析開發出一種較為精準且省時的預測方法來提升冶金工業中金屬粉末的製造效率。首先，金屬粉末氣霧法製程中流場涉及的維度過於龐大，模擬整個流場非常耗時且不切實際，我們設法透過單相流的模擬來縮小計算範圍，同時進行網格獨立性檢測以及時域上的分析來確認流場是否進入穩態；其次我們詳細地介紹模擬此流場背後的理論架構以及破裂模型，經過長時間的計算後，我們分析模擬的結果，並且透過整合單相流以及流體不穩定性理論進行預估，發現兩者在第一次破裂以及第二次破裂的誤差值均小於5%，而第三次破裂的誤差值也僅在13%左右，此預估方法大大地節省了計算成本。

關鍵字

氣霧法製程 ； 流體不穩定性 ； 計算流體力學

並列摘要

Metal powder production by gas atomization method is a significant part of the metallurgy industry, however, how to precisely control the size of metal powder product is still a challenging problem. This thesis aims to develop a more precise and time-saving method to estimate size distribution of metal powder product in order to boost the efficiency in metallurgy industry. First, the scope of the simulation for gas atomization process is beyond our study, simulating the full domain of flow field is time-consuming, we attempt to reduce the calculation domain by doing single phase simulation, mesh independence check is conducted simultaneously. We also analyzed the single phase simulation temporally in order to confirm if the flow field reached steady state. Second, we introduced the numerical models and breakup models adopted in simulation in detail. Finally, we compared the simulation results to our prediction method based on the combination of single phase flow simulation and instability theories. We found the error is less than 5% in primary breakup and secondary breakup, and the error is about 13% in third breakup, such prediction method does reduce the calculation cost drastically.

並列關鍵字

Gas atomization process ； Fluid instability ； CFD

參考文獻

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