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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

ENHANCEMENT AND CONTROL OF LOCAL HEAT TRANSFER COEFFICIENTS BY LOADING SOFT MAGNETIC PARTICLES IN A GAS FLOW

Get access (open in a dialog) DOI: 10.1615/IHTC10.2370
pages 91-96

Resumo

The enhancement of local heat transfer coefficients from hot wall to cooling air was achieved by controlling the motion of soft magnetic particles with permanent magnets in a vertical channel. The present investigation focuses on parameters which influence the characteristics of heat transfer: particle mass loading, magnetic field strength, particle time constant and gravity direction. An augmentation of local heat transfer coefficient was obtained by up to 60% by loading 145 µm Nickel-Zinc-Ferrite particles, which have a large particle time constant for velocity field, at a particle mass loading of 1.6 in a downward flow. In both downward and upward flow directions, turbulence attenuation due to the presence of particles was observed, which could not have contributed to heat transfer enhancement. The increase in heat transfer can he attributed to increasing the heat capacity in the thermal boundary layer with transverse magnetic force.