The Paton Welding Journal, 2013, №04



2013 №04 (12)

2013 №04 (02)

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The Paton Welding Journal, 2013, #4, 2-7 pages  

NUMERICAL MODELLING OF HEAT TRANSFER AND HYDRODYNAMICS IN LASER-PLASMA TREATMENT OF METALLIC MATERIALS

Yu.S. BORISOV, V.F. DEMCHENKO, A.B. LESNOJ, V.Yu. KHASKIN and I.V. SHUBA

E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine
 
 
Abstract
An approximate mathematical model is proposed to describe thermal and hydrodynamic processes occurring in combined laser-plasma cladding. The scheme of a rapidly moving heat source, which generalises the known N.N. Rykalin's scheme for a case of combined convective-conductive heat transfer in molten metal, is considered. Densities of the different-power laser and plasma heat sources are assumed to be distributed on the plate surface by the normal law, having different radii of heat spots. The combined heat spot is assumed to be additive. The equation of local heat balance on the surface of a workpiece allows for heat transfer by radiation and heat losses for evaporation. It is assumed that motion of the melt under the indirect-action plasma heating conditions is driven by the Archimedes buoyancy force and thermocapillary force. Verification of the mathematical model was carried out, and results of calculation experiments on investigation of the penetration zone under the effect of the laser and combined laser-plasma heat sources are described. It is shown that the Marangoni force is a dominant force factor determining hydrodynamics of the melt. The effect of convective energy transfer on formation of the molten zone was studied. 8 Ref., 4 Tables, 8 Figures.
 
 
Keywords: laser-plasma cladding, thermal and hydrodynamic processes, modelling, heat transfer, heat balance, cladding, penetration zone, Marangoni force
 
 
Received:                24.01.13
Published:               28.04.13
 
 
References
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