The potential of micromixers for contacting of disperse liquid phases

The dispersion of two immiscible fluids in a static micromixer comprising i nterdigital channels with corrugated walls was investigated using silicon o il 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 microm ixer and operating conditions. Dispersions with average droplet sizes as sm all as 5.6 mu m and monomodal size distributions having small standard devi ations of the droplet size down to 3.6 mu m could be generated using the mi cromixer. The droplet size decreased with increasing total flow and ratio o f 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. Gen erally, the silicon oil - dyed water dispersion showed smaller average drop let sizes and were more stable compared to the dispersions based on silicon oil and pure water.