Transient behaviour of deposition of liquid metal droplets on a solid substrate

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• 作者：J. Chapuis ; E. Romero ; F. Soulié ; C. Bordreuil ; G. Fras
• 刊名：Heat and Mass Transfer
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：52
• 期：10
• 页码：2283-2292
• 全文大小：921 KB
• 刊物类别：Engineering
• 刊物主题：Engineering Thermodynamics and Transport Phenomena
  Industrial Chemistry and Chemical Engineering
  Thermodynamics
  Physics and Applied Physics in Engineering
  Theoretical and Applied Mechanics
  Engineering Fluid Dynamics
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1181
• 卷排序：52

文摘

This paper investigates the mechanisms that contribute to the spreading of liquid metal macro-drop deposited during Stationary Pulsed Gas Metal Arc Welding on an initially cold solid workpiece. Surface tension and inertial effects take an important part in the behaviour of the liquid metal macro-drop, but in this configuration the influence of energetic effects can also be significant. The experimental results are discussed in the light of dimensional analysis in order to appreciate the influence of the process parameters and the physical mechanisms involved on the spreading of a macro-drop. A law is established to model forced non-isothermal spreading.List of symbolsc_pSpecific heat (J kg−1 K−1)d_wWire diameter (m)DMacro-drop diameter (m)fFrequency (Hz)gGravity (m s−2)hHeight of the macro-drop (m)IWelding current (A)LEnthalpy of melting (J kg−1)L_dCharacteristic length of the droplet (m)PWelding power (W)RBase radius of the macro-drop (m)rRadius of the droplet (m)tTime (s)T₀Initial temperature of the workpiece (K)T_dTemperature of the droplet (K)T_fFusion temperature (K)T_mTemperature of the macro-drop (K)u_dDroplet velocity (m s−1)uVelocity of the contact line (m s−1)UVoltage (V)VVolume of the macro-drop (m3)v_dMetal input by time unit (m3 s−1)V_wWire feed speed (m s−1)BoBond number (ρ g R2 γ−1)CaCapillary number (μ u γ−1)PePeclet number (ρ c_p R u γ−1)PrPrandtl number (μ c_p λ−1)ReReynolds number (ρ u D μ−1)WeWeber number (ρ u_d2 R γ−1)ZOhnesorge number (μ ρ−0.5 γ−0.5 R−0.5)γSurface tension (N m−1)μViscosity (kg m−1 s−1)ρDensity (kg m−3)λThermal conductivity (W m−1 K−1)θContact angle (rad)