非傳輸型井式直流水蒸氣電漿火炬內部流場模擬

Steam Plasma Flow Simulation of Non-Transferred Well-Type DC Torch

呂紹陽(Shao-Yang Lyu)

指導教授 ： 陳夏宗 ； 趙修武

中原大學/工學院/機械工程研究所/碩士(2009年)

https://doi.org/10.6840/cycu200901317

摘要

本研究在假設二維軸對稱與穩態條件下，以有限體積法聯立求解連續方程式、動量方程式、能量方程式、紊流方程式以及電流連續方程式，使用安培定律計算流場電流分佈，利用歐姆定律計算磁場大小，以分析電漿火炬內部電漿氣體流場基本特性。本研究使用虛擬網格技巧，利用計算區間分割進行平行化計算，以縮短計算時間。本研究利用上述數學模型及數值方法，模擬非傳輸型井式直流水蒸氣電漿火炬流場，先使用水蒸氣質量流率為5 g/s與電流為180 A的實驗結果，以決定在該工作條件下電漿火炬內部陰極最大電流密度約為3.73×10^7 A/m2，電弧長度約為234 mm。在利用此條件以得到當電流為125~200 A與質量流率為3.01~7.78 g/s時，陰極最大電流密度約為2.07~4.14×10^7 A/m2，電弧長度約在210~330 mm之間，電壓約在400~545 V之間，出口處平均溫度約在8200~11000 K之間，出口處平均速度約在900-2300 m/s 之間。

關鍵字

水蒸氣電漿 ； 非傳輸型井式火炬 ； 數值模擬

並列摘要

Based on steady and axis-symmetric assumption, this research employs a parallelized scheme based on MPI functions to simulate the flow field inside plasma torch with taking the induced electrical and magnetic effects into account, where magneto-hydrodynamic equations, including the continuity equation, the momentum equations, the energy equation, the current continuity equation and the turbulence transport equations are solved by a finite volume discretization in a segregated manner. By the comparison with experimental measurement mass flow rate 5 g/s and current 180 A, maximum current density about cathode is approximately 3.73107 A/m2, and the arc length is about 234 mm. The numerical predictions suggest that with current of 125-200 A and mass flow rate of 3.01-7.78 g/s, the maximum current density of cathode 2.07-4.14107 A/m2, the arc length 210-330 mm, the electrical potential 400-545 V, the average temperature of the nozzle exit 8200-11000 K and the average velocity of the nozzle exit 900-2300 m/s.

並列關鍵字

non-transferred well-type torch ； Steam plasma ； numerical simulation

參考文獻

24.許坤霖，「基於軸對稱假設之直流電漿火炬數學模型建立與數值模擬」，中原大學機械工程研究所博士論文，2009。

2.Scott D. A., Kovitya P. and Haddad G. N., “Temperature in the plume of a dc plasma torch,” J. Appl. Phys. 66, pp. 5232-5239, 1989.

3.Dilawari A. H., Szekely J. and Westhoff R., “An Assessment of the Heat and Fluid Flow Phenomena Inside Plasma Torches in Nom-transferres Arc Systems,” ISIJ Int. 30, pp. 381-389, 1990.

4.Westhoff R. and Szekely J., “A model of fluid, heat flow, and electromagnetic phenomena in a non-transferred arc plasma torch,” J. Appl. Phys. 70, pp. 3455-3466, 1991.

5.Westhoff R., Dilawari A. H. and Szekely J., “A Mathematical Representation of Transport Phenomena Inside a Plasma Torch,” Mater. Res. Soc. Symp. Proc. 199, pp. 213, 1991.