直流电弧等离子体炬的数值模拟研究
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摘要
本文建立了直流电弧热等离子体炬的三维模型,利用流体动力学软件FLUENT对氮气热等离子体温度及速度的空间分布进行了数值模拟,并在此基础上研究了工作气体流量的变化对炬内热等离子体传热与流动特性的影响效应。研究结果表明:等离子体温度的最高值出现在阴极附近,并随着轴向距离的增加而减小;等离子体速度则随着轴向距离的增加而增加,在炬出口处达到其速度的极大值;工作气流量的增加对炬内的温度分布影响不大,但等离子体温度呈现出随工作气流量的增加而减小的趋势。
In this paper, a three dimensional model of DC arc thermal plasma torch was established. The CFD software FLUENT was then used to simulate the spatial distribution of temperature and velocity for nitrogen thermal plasma, and the influence of the working gas flow on the spatial distribution of temperature were studied base on the model. The results show that the highest plasma temperature occurs near the cathode and decreases with increasing the axial distance, while the situations will reverse for plasma velocity and it reaches the maximum at the torch exit. There was no significant effect on the spatial distribution of plasma temperature by increasing the working gas flow rate, while the plasma temperature tends to decrease as increasing the working gas flow rate.
In this paper, a three dimensional model of DC arc thermal plasma torch was established. The CFD software FLUENT was then used to simulate the spatial distribution of temperature and velocity for nitrogen thermal plasma, and the influence of the working gas flow on the spatial distribution of temperature were studied base on the model. The results show that the highest plasma temperature occurs near the cathode and decreases with increasing the axial distance, while the situations will reverse for plasma velocity and it reaches the maximum at the torch exit. There was no significant effect on the spatial distribution of plasma temperature by increasing the working gas flow rate, while the plasma temperature tends to decrease as increasing the working gas flow rate.
引文
[1] Boulos M I, Fauchais P and P fender E. Thermal Plasmas:Fundamentals and Applications[M]. New York Plenum Press, 1994.
[2] Scott D A, Kovitya P, Haddad G N. Temperatures in the plume of a DC plasma torch[J]. Journal of Applied Physics, 1989, 66(11):5232-5239.
[3] Westhoff R, Szekely J. A model of fluid, heat flow, and electromagnetic phenomena in a non-transferred arc plasma torch[J]. Journal of Applied Physics, 1991, 70(7):3455-3466.
[4] Deng J, Li Y J, Xu Y X, et al. Numerical simulation of fluid flow and heat transfer in a DC non-transferred arc plasma torch operating under laminar and turbulent conditions[J]. Plasma Science and Technology, 2011,13(2):201-207.
[5] Blais A, Proulx P, Boulos M I. Three-dimensional numerical modelling of a magnetically deflected DC transferred arc in argon[J]. J. Phys. D:Appl. Phys. 2003,36(5):488-496.
[6] Hsu K C, Etemadi K, Pfender E. Study of the freeburning high-intensity argon arc[J]. J. Appl. Phys.,1983, 54(3):1293-1301.
[7] Pfender E, Selvarajan V, Padmanabhan P V A et al. Effect of powder loading on the excitation temperature of a plasma jet in DC thermal plasma spray torch[J]. Current Applied Physics, 2007(7):186-192.
[8] Fang M T C, Szenteb R N, Goldmana T I D et al.Modification of electrode materials for plasma torches[J].Surface and Coatings Technology, 2005, 200:254-257.
[9]陈伦江,唐德礼,程昌明等.双阳极等离子体炬的磁流体动力学分析[J].高电压技术, 2013, 39(7):1724-1728.
[10] Zhou Q, Li H, Xu X, et al. Comparative study of turbulence models on highly constricted plasma cutting arc[J]. Journal of Physics D:Applied Physics, 2009, 42(1):1-14.
[2] Scott D A, Kovitya P, Haddad G N. Temperatures in the plume of a DC plasma torch[J]. Journal of Applied Physics, 1989, 66(11):5232-5239.
[3] Westhoff R, Szekely J. A model of fluid, heat flow, and electromagnetic phenomena in a non-transferred arc plasma torch[J]. Journal of Applied Physics, 1991, 70(7):3455-3466.
[4] Deng J, Li Y J, Xu Y X, et al. Numerical simulation of fluid flow and heat transfer in a DC non-transferred arc plasma torch operating under laminar and turbulent conditions[J]. Plasma Science and Technology, 2011,13(2):201-207.
[5] Blais A, Proulx P, Boulos M I. Three-dimensional numerical modelling of a magnetically deflected DC transferred arc in argon[J]. J. Phys. D:Appl. Phys. 2003,36(5):488-496.
[6] Hsu K C, Etemadi K, Pfender E. Study of the freeburning high-intensity argon arc[J]. J. Appl. Phys.,1983, 54(3):1293-1301.
[7] Pfender E, Selvarajan V, Padmanabhan P V A et al. Effect of powder loading on the excitation temperature of a plasma jet in DC thermal plasma spray torch[J]. Current Applied Physics, 2007(7):186-192.
[8] Fang M T C, Szenteb R N, Goldmana T I D et al.Modification of electrode materials for plasma torches[J].Surface and Coatings Technology, 2005, 200:254-257.
[9]陈伦江,唐德礼,程昌明等.双阳极等离子体炬的磁流体动力学分析[J].高电压技术, 2013, 39(7):1724-1728.
[10] Zhou Q, Li H, Xu X, et al. Comparative study of turbulence models on highly constricted plasma cutting arc[J]. Journal of Physics D:Applied Physics, 2009, 42(1):1-14.