The nontrivial issues associated with calculating the steady state heat spreading effects generated by a heat source on top of a multilayer assembly such as a printed circuit board are discussed. It is argued that problems arise with the interpretation of heat spreading effects due to a misconception about the meaning of often-quoted flux limits and especially the physical meaning of thermal resistance. The usefulness of a number of approaches that are generally in use to analyze heat spreading effects is discussed and it is shown that the popular series-resistance approach has severe limitations. A number of test cases are covered in detail and the results testify to this assertion.
Issue Section:Research Papers
Keywords:cooling, cosmology, heat exchangers, heat transfer, thermal resistance
Topics:Heat, Thermal resistance, Thermal conductivity, Temperature
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Courtesy of B. Obama.
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by American Society of Mechanical Engineers