Peter T. While1, Larry K. Forbes1,
Stuart Crozier2
1School of Maths and Physics,
University of Tasmania, Hobart, TAS, Australia; 2School of
Information Technology and Electrical Engineering, University of Queensland,
Brisbane, QLD, Australia
Excessive
heating of gradient coils is a considerable concern. An analytic model is
presented for calculating theoretically the spatial temperature distribution
for cylindrical gradient coils. The model includes Ohmic heating due to
current density in resistive material, thermal conduction through a copper
layer and an epoxy former, and radial heat loss to the environment. A great
number of coil parameters can be varied, including geometry, electrical and
thermal properties, and results are shown for a standard x-gradient coil
under three different types of cooling. In addition, temperature rise-times
are predicted using a time-dependent solution for hot spot temperature.