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Magnetofluidization of fine magnetite powder
J M Valverde1, M J Espin, M A S Quintanilla
1Department of Electronics and Electromagnetism, University of Seville, Avenida Reina Mercedes s/n, 41012 Sevilla, Spain.
Summary
Magnetofluidized beds of cohesive magnetite particles show enhanced stability and expansion with a magnetic field. Applying the field during fluidization significantly increases bed tensile strength by forming particle chains.
Area of Science:
- Materials Science
- Chemical Engineering
- Fluid Dynamics
Background:
- Magnetofluidized beds typically use noncohesive magnetic particles.
- This study investigates naturally cohesive fine magnetite particles.
- Cohesive powders exhibit stable fluidization even without an external magnetic field.
Purpose of the Study:
- To investigate the behavior of cohesive magnetite particles in a magnetofluidized bed under a cross-flow magnetic field.
- To determine the effect of magnetic field application modes on bed stability and tensile strength.
- To analyze experimental data using theoretical models of magnetic surface stresses.
Main Methods:
- Experimental investigation of a fluidized bed of fine magnetite particles.
- Application of a cross-flow magnetic field in two modes: H off-on and H on-on.
- Measurement of bed tensile strength under different magnetic field conditions.
Main Results:
- The magnetic field extends the stable fluidization range and enhances bed expansion.
- In H off-on mode, tensile strength is minimally affected due to particle jamming.
- In H on-on mode, tensile strength significantly increases, indicating particle chain formation.
Conclusions:
- Cohesive magnetite particle beds show enhanced fluidization properties with magnetic fields.
- The mode of magnetic field application critically influences the bed's mechanical strength.
- Particle chain formation under magnetic influence enhances the tensile strength of fluidized beds.
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