冷却過程の熱伝達特性

抄録

Immersion cooling of a coated metallic object is discussed. Paradoxically, a coated object cools quicker than when the same object is bare. Through this phenomena the reader is introduced to various related topics. The main subject in the first issue is about the stability of the interface between liquid and vapor around the object and how this instability causes an early transition from film boiling to nucleate boiling state. In the second issue, the reader is introduced in more detail to film boiling by taking up the issue of film boiling on a long flat heater. A model for film boiling on such a heater is cited and effects of heater orientation and temperature on film boiling are qualitatively described based on this model. Finally, heat transfer in subcooled forced-flow helium is compared with that of supercritical helium, and ranges of heat flux are discussed for effective use of these two types of helium heat transfer.