A new kind of T-shaped microfluidic device with double pores at the junction was designed in this work Regular multiphase flows have been successfully formed in this new device and the liquid-liquid two-phase flow patterns in this new device were investigated. It was found that the droplet flows were easy to obtain in this new device at phase ratios (F_C/F_D) just higher than 0.5 with polydispersity index (δ) less than 3.5%, which were much smaller than the previous T-shaped microchannels. Short plugs, relative length L/w<1.4, were produced and a repulsed effect between the initial droplets was observed with the alternating droplet formation. Besides, the effect of the two-phase flow rates on the plug length and the droplet diameter was investigated by analyzing the periodic fluctuation flow from the two pores. Considering the mutual effect of two phase flows and the equilibrium between the shearing force and the interfacial tension, models were developed for presenting the mechanisms of dispersion.

Key words: T-shaped; microfluidic; double pores; multiphase flow