Abstract
Based on numerical solutions of the equation of motion of a particle in a gas jet modeled by the Reynolds-averaged Navier–Stokes equations, the features of transporting powder particles to the working zone of laser-based directed energy deposition are investigated. The propagation of a gas jet in a confined space in the presence of obstacles in the form of a substrate and a wall of a part is considered. A solution determining the gas-dynamic parameters of the jet is obtained, and the results of calculating its velocity field are presented. The influence of gas-dynamic parameters on the trajectories of the powder particles is analyzed. It is shown that these parameters determine the amount of model material involved in the formation of the geometry of the part.
Highlights
Laser-based directed energy deposition (L-DED) is an actively developing additive technology [1] that has been successfully introduced into the modern production cycles of metal alloy products [2,3,4,5] and allows for the repair of worn surfaces of parts [6,7]or the application of special coatings on products [8]
The velocity field of the carrier gas in a confined space in the presence of obstacles is calculated using the Navier–Stokes equations averaged by Reynolds together with the turbulence model k-ε
Themm number of nodes for meshcases consisted of triangular the andsame rectangular
Summary
Laser-based directed energy deposition (L-DED) is an actively developing additive technology [1] that has been successfully introduced into the modern production cycles of metal alloy products [2,3,4,5] and allows for the repair of worn surfaces of parts [6,7]or the application of special coatings on products [8]. Despite several advantages over traditional methods of manufacturing and surfacing, the technology is complex, with many technological parameters that affect both the properties of the product and the economic indicators of its manufacture. The technological parameters of the traverse speed and the powder feed rate strongly affect the height [9] and width [10] of the deposited layer, which determine the size of the melt bath and affect the hydrodynamic stability. The hydrodynamic stability of the process, in turn, affects the surface quality of the manufactured product [11]. An important aspect is the powder capture efficiency (PCE). The meaning of this efficiency lies in the amount of material involved directly in the formation of the product. Such a spread of PCE is caused by the design of gas–powder nozzles, the roughness of transport channels, and the sphericity of the model material
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