Study Of Bubble Formation Dynamics And Uniformity In Viscous Fluids In Parallel Microchannels

In the last decade,the micro-chemical technology has become one of the frontiers in chemical engineering owing to the high efficiency,easy to control and high flexible character.The bubble formation and manipulation in parallelized microchannels are the basis for the study on numbering-up process for micro-chemical technology.The aim of this report is to study the dynamics,mechanism and uniform size of air bubbles in highly viscous glycerol-water mixtures in a microfluidic device with two parallelized microchannels by using a high-speed digital camera.Experiments were conducted in polymethyl methacrylate(PMMA)microchannels with a cross-section of 400×400?m.Air bubbles were produced in glycerol–water mixtures with a number of concentrations of surfactant sodium dodecyl sulfate(SDS).The growth of bubbles is studied under the effect of liquid and gas flow rate and liquid viscosity.The bubble formation process can be classified in two stages,expansion stage with a low slope and breakup stage with relatively high slope.The scaling law for the prediction of bubble size was developed.The relative deviation of bubble length in parallel microchannels E(L)was studied and it was found that E(L)decreases with the increase of liquid flow rate and liquid viscosity and increases with the increase of gas flow rate.Four different microfluidic devices are studied and finally microfluidic device 1 with open area at both ends yields the more uniform bubbles.