This study evaluates flow instability and void fraction in a fractal-like branching microchannel network. The flow network is characterized by set branching ratios for channel length and width of 1/2 and 2, respectively, and features five branching levels. The hydraulic diameter of the channels ranged from 308μm at the inlet to 143μm at the outlet. Test were performed using water heated to an 88°C at the inlet with a mass flow rate of 10g/min. Heat fluxes of 1.76 W/cm2 and 2.64 W/cm2 were applied to the test device for the given flow rate. An upstream control valve was used to throttled the flow with a pressure drop approximately 100 times larger than the pressure drop across the test device. For the cases with and without throttling results for inlet pressure oscillation frequency and vapor activity at the inlet of the test device are compared. In addition, time averaged void fraction is compared for each branching level with and without throttling and is compared to predictions from a 1-D model. Results show good agreement between model and experiments for the average void fraction although local values differ significantly.

This content is only available via PDF.
You do not currently have access to this content.