Characterisation of bubbles formed in a cylindrical T-shaped junction device

Analytical modeling andin situmeasurement of void formation in liquid composite molding processes

“…The second reason is the influence of liquid velocity on the dynamic contact angle which can change the liquid wettability and void formation. [26,27] The water glycerol and surfactant mixture are a partially wetting liquid at high velocity and the dynamic contact angle can be increased. Therefore, the wettability property and void formation may be slightly different at high liquid velocity and the corresponding high modified capillary number.…”

Monitoring of an ascending air bubble in a viscous fluid/fiber matrix medium using a phased array transducer

“…The gas is injected at a flow Q 2 and is sheared by the main flow Q 1 . Due to the constancy of flows Q 1 and Q 2 , the volume of sheared air is constant, thus generated bubbles are of the same size [6,7]. Increasing the flow rate Q 2 increases the volume of sheared air; this produces calibrated air bubbles of different sizes.…”

“…2(a)). This 47V100 silicone oil is characterized at standard conditions of pressure p = 1 bar and temperature T = 25°C by a density ρ l = 965 kg/m 3 , a dynamic viscosity ν l = 100 mm 2 /s, resulting in a kinematic viscosity η l = 100 · 10 −6 × 965 = 96.5 mPa s. Other physical parameters such as surface tension γ l = 20 mN m and static contact angle θ s = 13°can be neglected in the bubble ascension at low Reynolds numbers, but in the dynamic of the bubble formation [6][7][8]. The second part of the experimental device generates calibrated air bubbles in a viscous fluid by shearing air at the junction of two capillaries (Fig.…”

“…The associated ultrasound and video measurement equipment is detailed. Bubbles of different sizes are generated at regular intervals using a technique based on the shearing of a gas in two converging capillaries [6,7]. In this case, the air is sheared at the junction of capillaries by a flow of silicone oil.…”

Microfluidic methods to study emulsion formation

“…The effect of contact angle in the squeezing regime is the same for bubbles as for droplets, as long as the liquid phase completely wets the channel wall; however, absence of such a pre-wetting film can lead to capillary instabilities and the formation of bigger bubbles. And in the dripping regime, the bubble will adopt a cylindrical shape (Ben Abdelwahed et al 2012;Wielhorski et al 2012).…”