A novel method for producing unequal sized droplets in micro- and nanofluidic channels

We propose a novel method for producing unequal sized droplets through breakup of droplets. This method does not have the disadvantages of the available methods and also reduces the dependence of the droplets volume ratio on the inlet velocity of the system by up to 26 percent. The employed method for investigating the proposed system relies on 3D numerical simulation using the VOF algorithm and the results have been obtained with various valve ratios for both the micro- and nanoscale. The results indicate that the droplet length during the breakup process increases linearly with time. The droplet length at the nanoscale is smaller than that at the micro scale. It has been shown that the maximum local capillary number in this system is 2.5 times the average capillary number. Therefore one can use the analytical theories based on the low capillary number assumptions to investigate the method. Graphical abstract