In this work, a train of confined bubbles inside a millimetric cylindrical T-junction device is studied. Calibrated bubbles need to be known precisely for multiphase phase flow applications. Experimental results of bubble formation and transport processes will be presented and discussed. For a liquid-gas flow, we will demonstrate how the wetting behaviour plays a significant role on the formation and motion of the bubble. (c) 2012 Elsevier Ltd. All rights reserved.