Gas-assisted evaporative cooling of high density electronic modules

Reliable operation of advanced microelectronic components in three-dimensional packaging configurations necessitates the development of cooling systems capable of removing high heat fluxes and very high heat densities. A recently patented thermal management technique, using high velocity flow of a liquid-gas mixture in the narrow channels between populated substrates, appears to provide such a thermal transport capability. A prototype, high packaging density module, relying on this approach, has been successfully operated and a research study, focusing on the heat transfer rates attainable with this technique in a single, asymmetrically-heated channel has been completed. This paper begins with a description of this gas-assisted evaporative cooling approach, its advantages in thermal packaging of microelectronics, and its implementation in a prototype high-performance computer module. Attention is then paid to theoretical considerations in the flow of gas-liquid-vapor mixtures in narrow parallel plate channels and to the design and operation of an appropriate experimental apparatus. Next, experimental results for the wall temperature, heat transfer coefficients, and pressure drops are presented and compared to theoretical predictions. The paper concludes with a discussion of the thermal packaging potential of this novel thermal management technique