Effects Of The Length Of A Cylindrical Solid Shield On The Entrainment Of Ambient Air Into Turbulent And Laminar Impinging Argon Plasma Jets

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	Effects Of The Length Of A Cylindrical Solid Shield On The Entrainment Of Ambient Air Into Turbulent And Laminar Impinging Argon Plasma Jets
	Wang HX(王海兴); Chen X(陈熙); Pan WX(潘文霞)
刊名	Plasma Chemistry And Plasma Processing
	2008
通讯作者邮箱	cx-dem@mail.tsinghua.edu.cn
页码	85-105
关键词	Impinging Plasma Jet Air Entrainment Solid-Shield Effect Materials Processing Modeling High-Velocity Gas Shroud Deposition Diffusion Substrate Flow
ISSN号	0272-4324
通讯作者	Chen, X (reprint author), Tsinghua Univ, Dept Engn Mech, Beijing 100084, Peoples R China.
中文摘要	When materials processing is conducted in air surroundings by use of an impinging plasma jet, the ambient air will be entrained into the materials processing region, resulting in unfavorable oxidation of the feedstock metal particles injected into the plasma jet and of metallic substrate material. Using a cylindrical solid shield may avoid the air entrainment if the shield length is suitably selected and this approach has the merit that expensive vacuum chamber and its pumping system are not needed. Modeling study is thus conducted to reveal how the length of the cylindrical solid shield affects the ambient air entrainment when materials processing (spraying, remelting, hardening, etc.) is conducted by use of a turbulent or laminar argon plasma jet impinging normally upon a flat substrate in atmospheric air. It is shown that the mass flow rate of the ambient air entrained into the impinging plasma jet cannot be appreciably reduced unless the cylindrical shield is long enough. In order to completely avoid the air entrainment, the gap between the downstream-end section of the cylindrical solid shield and the substrate surface must be carefully selected, and the suitable size of the gap for the turbulent plasma jet is appreciably larger than that for the laminar one. The overheating of the solid shield or the substrate could become a problem for the turbulent case, and thus additional cooling measure may be needed when the entrainment of ambient air into the turbulent impinging plasma jet is to be completely avoided.
类目[WOS]	Engineering, Chemical ; Physics, Applied ; Physics, Fluids & Plasmas
研究领域[WOS]	Engineering ; Physics
关键词[WOS]	HIGH-VELOCITY ; GAS SHROUD ; DEPOSITION ; DIFFUSION ; SUBSTRATE ; FLOW
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000253494300007
公开日期	2009-08-03 ; 2009-09-14
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/26124]
专题	力学研究所_力学所知识产出(1956-2008)
推荐引用方式 GB/T 7714	Wang HX,Chen X,Pan WX. Effects Of The Length Of A Cylindrical Solid Shield On The Entrainment Of Ambient Air Into Turbulent And Laminar Impinging Argon Plasma Jets[J]. Plasma Chemistry And Plasma Processing,2008:85-105.
APA	王海兴,陈熙,&潘文霞.(2008).Effects Of The Length Of A Cylindrical Solid Shield On The Entrainment Of Ambient Air Into Turbulent And Laminar Impinging Argon Plasma Jets.Plasma Chemistry And Plasma Processing,85-105.
MLA	王海兴,et al."Effects Of The Length Of A Cylindrical Solid Shield On The Entrainment Of Ambient Air Into Turbulent And Laminar Impinging Argon Plasma Jets".Plasma Chemistry And Plasma Processing (2008):85-105.