High-frequency formation of bubble with short length in a capillary embedded step T-junction microdevice

The performances of slug flow gas-liquid reactors are mostly determined by slug length, especially for the high gas-liquid flow rate ratio condition. This work is the first time to report the short bubble generated with high frequency in a capillary embedded step T-junction microdevice. The aspect ratio of bubble could be around 0.5 with a frequency higher than 750 s(-1) when the gas-liquid flow rate ratio is even higher than 5. The specific surface area of the generated gas-liquid microdispersion system is larger than 10,400 m(2)/m(3). The short bubble formation process includes two periods, and its formation mechanism is mainly because of the relatively higher pressure drop in the step T-junction, which provides a much higher breakup force for the squeezing flow. Finally, two models are developed to predict the bubble frequency and volume. This work provides a highly promising dispersion technology for the gas-liquid process intensification in microreactors.