The influence of channel intersection angle on droplets coalescence process

The present study investigates the influence of channel intersection angle on the droplets coalescence process using high-speed microscope and micro-PIV system. Spontaneous coalescence and delayed coalescence occur when the droplets meet at low flow rate conditions. The film drainage time and critical capillary number are organized by recording the phenomena after droplets meet at channel junctions with different intersection angles. The microchannel junction structure details are taken for the in-depth understanding of droplets coalescence process. The experimental results show that the critical capillary number for droplets coalescence decreases with the increase of channel intersection angle, and increasing two-phase flow rates and intersection angle can reduce the film drainage time. It can be concluded that reducing the intersection angle may improve the coalescence efficiency.