Study of Evaporation Phenomena in Micro Channels

Two-phase convective flow in micro channels has numerous promising applications such as electronic cooling. This study investigates evaporation phenomena and capillary-driven heat in a rectangular micro channels structure with hydraulic diameters of 100 ~ 250nm and length of 75mm. The micro channels made of (110)-orientated silicon is fabricated by bulk micromachining. The temperature distributions in micro channels chip structure, as well as the induced evaporation mass flow rate of water, were measured under different heat flux and inclination angle. Thermal resistances were calculated to evaluate the chip cooling performance. The experimental results show that with an increase of the imposed heat flux, the evaporation mass flow rate increases and thermal resistance decreases. The effect of channel sizes and inclination angle on the heat transfer characteristics are also examined