A 500-μm-wide and 11-mm-deep cross-microchannel, which is made of copper and attached by a hydrophobic nanoporous membrane having a pore size of 0.22 μm and a porosity of 70%, is tested in the present study to examine the characteristics of gas/liquid two-phase flow in the microchannel in horizontal and vertical orientations during bubble venting via the hydrophobic nanoporous membrane. The mass flux tested in the present study is 5, 7.5, 10, and 12.5 kg/m 2 ·s. In addition, the quality in the present study is tested from 0 to 0.08. The effects of mass flux, quality, and microchannel orientation on both the gas/liquid two-phase flow pattern and the bubble venting efficiency are examined in the present experiment through direct flow visualization. The tested results show that the farthest bubble movement distance increases with quality. It is also found that the flow rate of residual gas with the vertical arrangement is larger than that of the horizontal orientation. This is because the buoyancy force is in favor of the horizontal configuration for providing more direct contact and such contact of the bubble and the membrane is helpful for bubble venting. Besides, it is found that the higher flow rate of residual gas leads to a higher-pressure drop gradient in the flow channel.
|Number of pages||10|
|Journal||Journal of Flow Visualization and Image Processing|
|State||Published - 1 Jan 2011|
- Bubble venting
- Porous membrane