Fluidization: Hydrodynamic Stabilization with a Magnetic Field

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Science  06 Apr 1979:
Vol. 204, Issue 4388, pp. 57-60
DOI: 10.1126/science.204.4388.57


Fluidization of magnetizable particles by a gas stream in the presence of a uniform applied magnetic field oriented parallel to the flow prevents the hydrodynamic instability that otherwise leads to bubbles and turbulent motion within the medium. The fluidized emulsion expands uniformly in response to gas flow speeds in excess of that at the incipient fluidization point, with transition from the quiescent stable state to bubbling occurring suddenly at a characteristic increased rate of flow. Experimental data demonstrate the dependence of this transition velocity on the intensity of the applied magnetic field, length of the bed, and type of magnetic solids. Data illustrate the pressure distribution through the bed medium, the bedflow characteristics, and other phenomena.