Review of Industrial Applications of Heat Transfer to Electronics

Applications of heat transfer to electronic components and devices are presented and discussed. The major objectives are to review the state of the art in such applications and to indicate the need for a better grasp of the science of heat transfer in aiding the creative engineering of new electronic devices operating at extreme conditions of temperature, heat flux, air density, etc. The recent rapid growth of heat-transfer applications to electronics is analyzed in terms of the changing specifications resulting from the introduction of the supersonic and hypersonic aircraft and missiles. The general thermal problem of a given piece of electronic equipment is discussed and analyzed in terms of different modes of heat transfer. A simple method of comparing heat removal by means of natural convection, radiation, forced convection, and evaporative cooling is presented in chart form. The design philosophy of heat-transfer applications to industrial electronic equipment is discussed. Four specific illustrations of industrial applications of heat transfer to electronic components and equipment are presented. The first describes use of heat transfer and fluid mechanics to predict accurately the thermal performance of a newly developed vacuum tube which dissipates 25 kw. The second presents the analysis and some samples of the cold-plate technique used to cool highly compact miniaturized electronic equipment. The third example discusses the recent development of high temperature vacuum tubes, which can operate reliably at ambient temperatures in excess of 250°C. The final illustration discusses evaporatively-cooled magnetic components, in particular, transformers, by means of fluorochemical dielectrics.