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Modelling and diagnostics of multiple cathodes plasma torch system for plasma spraying

Kirsten BOBZIN, Nazlim BAGCIVAN, Lidong ZHAO, Ivica PETKOVIC, Jochen SCHEIN, Karsten HARTZ-BEHREND, Stefan

《机械工程前沿（英文）》 2011年 第6卷 第3期   页码 324-331 doi: 10.1007/s11465-011-0125-2

摘要：

Usage of a multiple-arcs system has significantly improved process stability and coating properties in air plasma spraying. However, there are still demands on understanding and controlling the physical process to determine process conditions for reproducible coating quality and homogeneity of coating microstructure. The main goal of this work is the application of numerical simulation for the prediction of the temperature profiles at the torch outlet for real process conditions. Behaviour of the gas flow and electric arcs were described in a three-dimensional numerical model. The calculated results showed the characteristic triangular temperature distribution at the torch nozzle outlet caused by three electric arcs. These results were compared with experimentally determined temperature distributions, which were obtained with specially developed computed tomography equipment for reconstructing the emissivity and temperature distribution of the plasma jet close to the torch exit. The calculated results related to temperature values and contours were verified for the most process parameters with experimental ones.

关键词： plasma spraying     electric arc     three-cathode plasma torch     numerical simulation     computed tomography    

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环境信息系统——为水管理数字化（Water 4.0）铺平道路

Olaf Kolditz, Karsten Rink, Erik Nixdorf, Thomas Fischer, Lars Bilke, Dmitri Naumov, Zhenliang Liao,

《工程（英文）》 2019年 第5卷 第5期   页码 828-832 doi: 10.1016/j.eng.2019.08.002

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Towards an integrated modeling of the plasma-solid interface

Michael Bonitz, Alexey Filinov, Jan-Willem Abraham, Karsten Balzer, Hanno Kählert, Eckhard Pehlke, Franz

《化学科学与工程前沿（英文）》 2019年 第13卷 第2期   页码 201-237 doi: 10.1007/s11705-019-1793-4

摘要： Solids facing a plasma are a common situation in many astrophysical systems and laboratory setups. Moreover, many plasma technology applications rely on the control of the plasma-surface interaction, i.e., of the particle, momentum and energy fluxes across the plasma-solid interface. However, presently often a fundamental understanding of them is missing, so most technological applications are being developed via trial and error. The reason is that the physical processes at the interface of a low-temperature plasma and a solid are extremely complex, involving a large number of elementary processes in the plasma, in the solid as well as fluxes across the interface. An accurate theoretical treatment of these processes is very difficult due to the vastly different system properties on both sides of the interface: Quantum versus classical behavior of electrons in the solid and plasma, respectively; as well as the dramatically differing electron densities, length and time scales. Moreover, often the system is far from equilibrium. In the majority of plasma simulations surface processes are either neglected or treated via phenomenological parameters such as sticking coefficients, sputter rates or secondary electron emission coefficients. However, those parameters are known only in some cases and with very limited accuracy. Similarly, while surface physics simulations have often studied the impact of single ions or neutrals, so far, the influence of a plasma medium and correlations between successive impacts have not been taken into account. Such an approach, necessarily neglects the mutual influences between plasma and solid surface and cannot have predictive power. In this paper we discuss in some detail the physical processes of the plasma-solid interface which brings us to the necessity of coupled plasma-solid simulations. We briefly summarize relevant theoretical methods from solid state and surface physics that are suitable to contribute to such an approach and identify four methods. The first are mesoscopic simulations such as kinetic Monte Carlo and molecular dynamics that are able to treat complex processes on large scales but neglect electronic effects. The second are quantum kinetic methods based on the quantum Boltzmann equation that give access to a more accurate treatment of surface processes using simplifying models for the solid. The third approach are simulations of surface process that are based on density functional theory (DFT) and time-dependent DFT. The fourths are nonequilibrium Green functions that able to treat correlation effects in the material and at the interface. The price for the increased quality is a dramatic increase of computational effort and a restriction to short time and length scales. We conclude that, presently, none of the four methods is capable of providing a complete picture of the processes at the interface. Instead, each of them provides complementary information, and we discuss possible combinations.

关键词： plasma physics     surface science     plasma-surface modeling     DFT     nonequilibrium Green functions    

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标题 作者 时间 类型 操作

Modelling and diagnostics of multiple cathodes plasma torch system for plasma spraying

Kirsten BOBZIN, Nazlim BAGCIVAN, Lidong ZHAO, Ivica PETKOVIC, Jochen SCHEIN, Karsten HARTZ-BEHREND, Stefan

期刊论文

环境信息系统——为水管理数字化（Water 4.0）铺平道路

Olaf Kolditz, Karsten Rink, Erik Nixdorf, Thomas Fischer, Lars Bilke, Dmitri Naumov, Zhenliang Liao,

期刊论文

Towards an integrated modeling of the plasma-solid interface

Michael Bonitz, Alexey Filinov, Jan-Willem Abraham, Karsten Balzer, Hanno Kählert, Eckhard Pehlke, Franz

期刊论文