Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

George M. Lloyd
Department of Mechanical Engineering, University of Nevada/Reno

K. J. Kim
Department of Mechanical Engineering, University of Nevada/Reno

Simple physical arguments show that eddy current and magnetic flux profiles are quantitatively altered in a ferromagnetic medium subjected to transient applied magnetic fields sufficient to technically saturate the material. As a result, even beyond the addition of hysteresis losses, Joule heating in ferromagnetic differs substantially from the constant permeability case, and interpretation of magnetic flux measurements is greatly hindered. The thermo-magnetic problem arises in many applications, such as magnetoelastic non-destructive testing (NDE), induction heating, and high field magnetic environments. It is also well known that the magnetic properties of most ferromagnetic materials are sensitive to stress and temperature. For this reason, the desire also exists to associate bulk magnetic material parameters with microstructure features to enable generally useful correlations to be developed. The Jiles/Atherton/Sablik (JAS) class of phenomenological models potentially fit these requirements, although their use in modeling thermomagnetic effects has been limited, in part because of their non-linearity and in part because of limited experimental data available for their calibration and validation. In this paper we formulate methods for solving the coupled magnetostationary equation, and first law equation in conjuction with a JAS model which incorporates both temperature and stress dependencies. Boundary conditions are integrated using a high order Runge-Kutta scheme, while the interior elements are integrated directly from the differential anhysteretic susceptibilities using an explicit scheme.

THP-07 pages DOI: 10.1615/IHTC13.p2.70 Download article

Article price - $35.00

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