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Journal of Microwave Power
and Electromagnetic Energy (JMPEE) |
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TITLE |
Thermal Runaway in Electromagnetic
Heating, with Application to the Reheating of Cryopreserved
Biomaterials [PDF] |
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AUTHORS |
S. Evans
and J. Penfold 1993 28 2 84-92 |
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Abstract When the dielectric properties
of an electromagnetically heated material are temperature dependent, the
possibility of thermal runaway exists. Normally, unstable heating can be
overcome by heat conduction away from the overheated region, but in cases
where the heating rate is very high, thermal relaxation has limited or no
effect. We define three stability factors which indicate directly whether or
not thermal runaway can occur, irrespective of the heating rate and the
thermal properties of the heated material. These factors are dependent on the
material's dielectric properties, as well as the geometry and the orientation
with respect to the E-field, of any irregularities. They can be used to
provide clear guidelines to choices of source frequency and applicator
geometry, which are favorable for the intrinsic
control of thermal runaway. Experimental results are presented for a
spherical workpiece (representing a cryopreserved rabbit kidney) warmed from Key Words: EM heating, Thermal runaway,
Dielectric parameters, Cryopreservation. |
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