Title

The Investigation of Gravity-Driven Metal Powder Flow in Coaxial Nozzle for Laser Aided Direct Metal Deposition Process

Abstract

The quality and efficiency of laser-aided direct metal deposition largely depends on the powder stream structure below the nozzle. Numerical modeling of the powder concentration distribution is complex due to the complex phenomena involved in the two-phase turbulence flow. In this paper, the gravity-driven powder flow is studied along with powder properties, nozzle geometries, and shielding gas settings. A 3-D numerical model is introduced to quantitatively predict the powder stream concentration variation in order to facilitate coaxial nozzle design optimizations. Effects of outer shielding gas directions, inner/outer shielding gas flow rate, powder passage directions, and opening width on the structure of the powder stream are systematically studied. An experimental setup is designed to quantitatively measure the particle concentration directly for this process. The numerical simulation results are compared with the experimental data using prototyped coaxial nozzles. The results are found to match and then validate the simulation. This study shows that the particle concentration mode is influenced significantly by nozzle geometries and gas settings.

Department(s)

Mechanical and Aerospace Engineering

Sponsor(s)

Air Force Research Laboratory (Wright-Patterson Air Force Base, Ohio)
National Science Foundation (U.S.)
U.S. Army Aviation and Missile Command

Keywords and Phrases

Coaxial Nozzle; Direct Metal Deposition; Nozzle Design; Numerical Simulation; Powder Flow

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2006 American Society of Mechanical Engineers (ASME), All rights reserved.

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