The potential of micromixers for contacting of disperse liquid phases

The dispersion of two immiscible fluids in a static micromixer comprising interdigital channels with corrugated walls was investigated using silicon oil dispersed in dyed as well as pure water as test systems. Silicon oil and water flow rates between 20 mL/h to 500 mL/h and 150 mL/h to 700 mL/h were used, respectively. The experiments revealed the dependence of the average droplet size and size distribution on geometrical parameters of the micromixer and operating conditions. Dispersions with average droplet sizes as small as 5.6 μm and monomodal size distributions having small standard deviations of the droplet size down to 3.6 μm could be generated using the micromixer. The droplet size decreased with increasing total flow and ratio of the flow rates of the two liquids. In addition, a decrease of the droplet size was found when decreasing the channel width of the mixing device. Generally, the silicon oil – dyed water dispersion showed smaller average droplet sizes and were more stable compared to the dispersions based on silicon oil and pure water. Received: 5 January 1999 / Revised: 10 February 1999 / Accepted: 13 February 1999