本文研究目的是以自行發展之雷射與電漿火炬混合法製備奈米金屬微粒，結合電漿火炬之流場特性及金屬微粒的成核成長現象以數值模擬分析及實驗進行研究。

　　在數值分析方面，考慮噴嘴幾何、電漿火炬的流場特性，應用MHD發電理論、流體力學和氣動力學方程式以及相關數值方法，以計算流體力學分析軟體FLUENT計算在電漿火炬的速度場、壓力場和溫度場等流場特性。在奈米微粒成長理論是使用有限差分法，將奈米微粒成長理論中的數學模型離散預測生成粒子過程中的粒徑變化，其中考慮粒子間碰撞重熔行為的金屬蒸氣冷凝與單體分子濃度的平衡關係式、成核率方程式以及相關的奈米微粒成長尺寸的計算，將電漿火炬之速度分佈與溫度分佈代入到奈米微粒成長理論的計算中以瞭解電漿火炬對於粒子成長機制的影響。在實驗部份則是採用連續式，波長10.6μm的CO2雷射對照射鐵和鎳金屬材料引發金屬蒸氣，以電漿火炬偶合作用而生成奈米金屬微粒，利用電子顯微鏡(F-SEM)和能量散佈儀(EDS)做粒子尺寸與分佈分析以及成分分析。

　　在研究中可以得到不同氣流條件所產生的電漿流場特性對生成奈米金屬微粒時粒子特性的影響。經理論分析並輔以實驗結果進行比對，以作為日後從事生成奈米粒子相關研究的基礎。

　　The metallic nano-particles are generated by laser ablation with a plasma torch in this study. At various flow velocities of the plasma generated by an arc torch, the nucleation and solidification phenomena of the metallic particles have been simulated in the numerical analysis and evaluated by the experiments.

　　The aspects of the numerical analysis include the process parameters of the flow velocity, pressure, and temperature of the plasma. Using the computational fluid dynamics (CFD) software, the compressible flow problem with turbulence effects was solved. With the other approach of the mathematical formulation of the particle nucleation, condensation, and coagulation processes during the particle-flow interactions in flight, the formation of the nano-particle was simulated. In experiment, the temperature of the plasma torch was evaluated by the spectrum analysis, and the particle size and distribution were also observed. The experimental results show a good agreement with the numerical simulation.

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