Abstract:

The mechanisms for bubble and droplet formation in T-shaped microchannels were reviewed. Control parameters for bubble and droplet formation under three various mechanisms，i.e. squeezing mechanism，shearing rupture mechanism and squeezing-shearing rupture mechanism，were discussed. The results showed that the formation of confined bubble（droplet）is attributed to the squeezing mechanism and the bubble（droplet）size is controlled by gas/liquid flow rate ratio. The production of unconfined bubble（droplet）is attributed to the shearing rupture mechanism and is controlled by capillary number. The generation of bubble（droplet）in squeezing-dripping transition regime is attributed to the squeezing-shearing rupture mechanism and is controlled by both capillary number and gas/liquid flow rate ratio. The physical models for three different mechanisms，as well as the influence of viscosity ratio on bubble and droplet formation were introduced.

摘要：

综述了T形微通道内气泡（液滴）的生成机理。讨论了挤压机制、剪切机制以及挤压-剪切共同作用机制下气泡（液滴）生成控制因素，表明挤压机制发生于受限气泡（液滴）的生成，其生成尺寸主要由气液流量控制；剪切机制发生于未受限气泡（液滴）生成，主要由毛细数控制；挤压和剪切共同作用机制发生于挤压-滴状转变区内气泡（液滴）的生成，并由毛细数和流量比共同控制。同时介绍了3种不同机制的物理模型以及黏度比对气泡（液滴）生成的影响。