Electrodynamic Concentration of Non-ferrous Metallic Particles in the Moving Gas-powder Stream: Mathematical Modeling and Analysis

Yuze Huang,Ehsan Toyserkani,Mir Behrad Khamesee

doi:10.35840/2631-5068/6519

Abstract

The paper presents theory, modeling, and analysis of a novel electrodynamic concentration approach for submillimeter-sized conductive metal particles focusing in moving gas-powder stream. Such method is of particular interest in blown-powder feeding fabrication industry (e.g., powder-fed additive manufacturing) to generate a tightly focused powder stream. Conceptual design of a concentration generator is proposed with two different configurations: The doublet Halbach permanent magnet quadrupoles (doublet-Halbach-PMQs) and the doublet electromagnet quadrupoles (doublet-EMQs). Analytical models for magnetic forces and concentration angles were built. Numerical calculations were conducted for pure aluminum particles with a radius of <math xmlns='http://www.w3.org/1998/Math/MathML'> <mrow> <mn>50</mn><mo><</mo><msub> <mi>R</mi> <mi>p</mi> </msub> <mo>≤</mo><mn>500</mn><mtext> </mtext><mi>μ</mi><mi>m</mi></mrow> </math>. It was found that the magnetic force and the concentration angle increase with an increase of the particle size. The numerical results indicate that the proposed concentration generator with doublet-Halbach-PMQs configuration cannot be effectively used for small-size particle concentration. By contrast, the concentration generator with doublet-EMQs configuration under high frequency is capable to concentrate particles with a radius of <math xmlns='http://www.w3.org/1998/Math/MathML'> <mrow> <msub> <mi>R</mi> <mi>p</mi> </msub> <mo>></mo><mn>150</mn><mtext> </mtext><mi>μ</mi><mi>m</mi></mrow> </math>. The particles with a radius of <math xmlns='http://www.w3.org/1998/Math/MathML'> <mrow> <msub> <mi>R</mi>

Highlights

A major challenge in the blown-powder feeding fabrication techniques is to deliver the powder to precise spatial point to satisfy geometric precision
Inspired by the eddy current separation (ECS) technique and the associated magnetic force models, this paper investigates an innovative magnetic concentration approach to focus non-ferrous metallic particles in gas medium
As the nozzle diameter of the powder feeding process is typically smaller than 2 mm [1], the Halbach permanent-magnetbased quadrupoles (PMQs) is built with a compact geometry where the inner radius, outer radius and thickness are set as ri = 2 mm, ro = 10 mm and H = 1mm, respectively

Summary

Introduction

A major challenge in the blown-powder feeding fabrication techniques (e.g., powder-fed additive manufacturing [1]) is to deliver the powder to precise spatial point to satisfy geometric precision. The induced eddy current will react back to the applied field by generating a magnetic force that drags the particles towards to the field intensity decreasing direction.

Results

Conclusion