The objective of this research is to study the local heat transfer variations on micro-scale pin-fins in order to better understand the fundamental behavior of liquid flow boiling in miniature heat sinks. An improved understanding of these localized phenomena is crucial for developing heat-sinks for next generation high-performance electronics. The research approach involves the design, fabrication, characterization, and use of an array of unique thin-film temperature and heat flux sensors (50 x 50 micron in size) directly on the side of a copper micro-fin. The instrumented fin will be mounted in a specially designed miniature heat sinks to observe the gas-liquid two-phase flow pattern, flow instability, pressure loss, and heat transfer associated with liquid flow boiling in both staggered and aligned micro-pin-fin arrays. High-speed video imaging will be used to capture local and global flow patterns. The local (single pin) and global heat transfer and flow pattern, and global pressure drop data will be used to create empirical correlations and flow pattern-based models to predict the liquid flow boiling heat transfer in micro-pin-fin arrays. This work will benefit society by generating the knowledge needed to design and safely operate two-phase (boiling) miniature heat sinks that can remove larger amounts of heat from smaller areas more economically. This is necessary if the current pursuit of circuit integration and device miniaturization in electronics industry is to be continued in the future. Also, the micro-scale integrated temperature and heat flux sensors will significantly advance experimental techniques in basic heat transfer research. Further societal impact will result from training engineering students, recruiting and retaining students from underrepresented groups, and guiding them to graduate programs. Public outreach presentations will be developed to foster an interest in science and engineering among middle and high school students. The close collaboration between the universities will enhance knowledge transfer and expose the students to a more diverse educational experience.
