ROLE OF MICROSCALE HEAT TRANSFER IN UNDERSTANDING FLOW BOILING HEAT TRANSFER AND ITS ENHANCEMENT

摘要

Due to the trend towards miniaturization and intensification of processes, a large demand is placed on associated cooling/heating systems, for example, the intensification of chip power, heat exchange to micro-reactor, or reduced weight/volume in off shore applications and avionics. To meet this large demand, two-phase heating/cooling systems become increasingly necessary. Boiling heat transfer has long been recognized as one of the most efficient means for transferring very high heat fluxes at relatively low wall superheats. This has made boiling a very attractive technique to be used in a wide range of cooling technologies. In addition to this specific interest in boiling in microchannels, the general area of microscale heat transfer itself is receiving increasing attention. For example, environmental concerns in an increasing number of applications have necessitated the use of new working fluids (pure and blends) and natural fluids such as CO2 in refrigeration and in some process duties, where micro-technology is increasingly being considered, for heat transfer components. Thermal control in fuel cells, now proposed for small devices such as mobile phones, is an additional challenge, with implications extending to other micro-reactor uses and process intensification applications. Other related applications range from biological systems to industrial applications like: transportation, electronics, material processing, energy and environment.