Abstract: The flow ideality of bubbly microflow remains unclear even though it is vital for the design of microreactors, especially the ideality of bubble swarm microflow for large-scale gas-liquid microreaction processes. This work is the first time to report the ideality analysis of the microbubble swarm in a relatively large microchannel. The bubble swarm microflow has undergone two conditions: quasi-homogeneous plug flow and liquid phase/gas-liquid quasi-homogeneous phase two-phase laminar flow. Both the deviations of void fraction and bubble velocity from the ideal plug flow can divide into two parts, and the two transition points simultaneously happen at the velocity ratio of 1.25. There exists a critical capillary number to maintain the quasi-homogeneous plug flow, which could be regarded as the general laws for the design of gas-liquid microreactors. Finally, a novel model is developed to predict the bubble velocity. This work could be very helpful for the large-scale gas-liquid microreactors design.

Key words: Bubble swarm, Flow ideality, Viscous fluids, Gas-liquid microreactor

摘要： The flow ideality of bubbly microflow remains unclear even though it is vital for the design of microreactors, especially the ideality of bubble swarm microflow for large-scale gas-liquid microreaction processes. This work is the first time to report the ideality analysis of the microbubble swarm in a relatively large microchannel. The bubble swarm microflow has undergone two conditions: quasi-homogeneous plug flow and liquid phase/gas-liquid quasi-homogeneous phase two-phase laminar flow. Both the deviations of void fraction and bubble velocity from the ideal plug flow can divide into two parts, and the two transition points simultaneously happen at the velocity ratio of 1.25. There exists a critical capillary number to maintain the quasi-homogeneous plug flow, which could be regarded as the general laws for the design of gas-liquid microreactors. Finally, a novel model is developed to predict the bubble velocity. This work could be very helpful for the large-scale gas-liquid microreactors design.

关键词: Bubble swarm, Flow ideality, Viscous fluids, Gas-liquid microreactor