On Classification of Water-in-Oil and Oil-in-Water Droplet Generation Regimes in Flow-Focusing Microfluidic Devices

Abstract

The objective of this research work is to propose a phase diagram that can be used to find a proper operating condition for generating droplets of different types. It is found that the phase diagram of QR versus CaD can effectively classify the droplet generation into three vivid regimes: dripping, jetting and tubing. For the dripping regime, its operating condition is in the range of either CaD −4 and QR −3 CaD −4 and QR jetting regime, its operating condition is in the range of either CaD −2 and QR > 100 or CaD > 1.35 × 10−2 and QR > 1. For the tubing regime, its operating condition is in the range of CaD > 1.35 × 10−2 and QR < 1.

Keywords

• micro-droplet
• droplet generation regime
• phase diagram
• capillary number
• microfluidic
• dripping