(129d) Multiphase Mixing with Disrupted Flow for Enhanced Interfacial Area

Although micro-scale processing leads to significant heat and mass transfer performance enhancements, not all micro-channels are created equal, and interfacial surface area can be largely controlled by choosing appropriate channel configurations and fluid property combinations. Carbon dioxide mass transfer into water was measured with flow through specially designed channels configured to provide disrupted (or high shear) flow at liquid and vapor phase Reynolds numbers up to 400 and 60, respectively. Mass transfer kLa values as high as 20 s-1 were obtained, corresponding to interfacial specific surface area values higher than 10,000 m2/m3. Hence, experimental work with two-phase flows in microchannels shows that the inclusion of features to provide disrupted flow can substantially increase the vapor-liquid mass transfer over straight microchannels. Since the high shear rate is retained throughout the channel length, bubbly flow can be created and maintained with relative ease. We discuss our experimental values, provide additional experimental results, and compare our findings to published literature results for microchannel vapor-liquid contactors. The links between flow morphology and performance will be used to clarify how we can push the performance envelopes to the limit.