Microscale boiling heat transfer near the meniscus

Results are presented experimentally measuring the localized temperature profile due to microscale boiling of a silicon-Pyrex bonded wafer with a 100 mu m deep, 500 mu m wide and six mm long microchannel. Experiments were performed using an infrared camera equipped with a magnifying lens. By using a camera, the dynamic temperature profile is shown from the inside channel all the way out to where the temperature of the wafer reaches the bulk temperature of the heating source. Temperature profiles are shown for both water and methanol as the working fluid applying between five and twenty degrees Celsius of superheat to the bulk wafer. Using these results, a discussion of the relevant heat transfer modes and nondimensional numbers is given to gain insight into the range of influence that phase change in a microchannel has on the temperature of the wafer. Additionally, discussion is given about modeling of microscale phase change using a commercial fluid dynamics software package. The importance of these results with respect to implementation into the fuel intake manifold for a micro engine based portable power system is also discussed.