Type of Document Master's Thesis Author Fischer, Patrick URN etd-317182749721461 Title Numerical Simulation of Microwave Sintering of Zinc Oxide Degree Master of Science Department Mechanical Engineering Advisory Committee
Advisor Name Title Dr. J.R. Thomas Committee Chair Dr. E. P. Scott none Dr. T. E. Diller none Keywords
- zinc oxide
- microwave
- heat transfer
- permittivity
- thermal wave
Date of Defense 1997-05-08 Availability unrestricted Abstract Experiments at the University of Maryland Plasma Physics
Laboratory have discovered an unusual temperature
response in the form of a "thermal wave" which begins at
the center and propagates towards the surface of a zinc
oxide sample, when heated in a microwave cavity without
the presence of oxygen. This effect is believed to be
caused by the irregular temperature dependence of the
dielectric properties of zinc oxide, particularly dielectric
loss. Two thermocouple probes were used to measure the
temperature response in a small cylindrical sample of zinc
oxide packed in powder insulation, and heated in a
microwave oven. In order to determine if the unusual
response is caused by the dielectric properties, this work
uses a finite-difference mathematical model to simulate the
experiments, both for the case of zinc oxide heated in
ordinary air, as well as for the case of zinc oxide heated in
nitrogen. A revised version of the model is used to
determine if the thermocouple probe has any effect on the
temperature of the sample. The spatial and temporal
temperature distribution results from the model indicate
that the thermocouple probe has a negligible effect on the
results and that the "thermal wave" can be attributed to the
irregular temperature dependence of the dielectric loss of
the material.
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