Effect of gas expansion on the velocity of a Taylor bubble: PIV measurements

• Published in: International journal of multiphase flow Vol. 32; no. 10; pp. 1182 - 1190
• Main Authors: Sousa, R.G., Pinto, A.M.F.R., Campos, J.B.L.M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-10-2006; Elsevier
• Subjects: Drops and bubbles; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Instrumentation for fluid dynamics; Nonhomogeneous flows; Physics; PIV measurements; Taylor bubble; Taylor bubble expansion; Taylor bubble velocity; Taylor bubble expansion; Taylor bubble velocity; PIV measurements; Taylor bubble; Bubbles; Test facilities; Bubble ascent; Vertical pipe; Bubble growth; Particle image velocimetry; Experimental study; Velocity measurement
• ISSN: 0301-9322; 1879-3533
• DOI: 10.1016/j.ijmultiphaseflow.2006.06.002

The effect of gas expansion on the velocity of a Taylor bubble was studied experimentally. The velocity field in the liquid ahead of a Taylor bubble was measured by particle image velocimetry (PIV), and the bubble velocity was measured with two pairs of laser diodes and photocells. The experiments were done in a 7.0
m long vertical tube with a 32
mm internal diameter. Solutions of carboxymethylcellulose (CMC) polymer with weight percentages between 0.01% and 0.1% were used. The expansion of slug gas induces an increase in the bubble velocity and a corresponding displacement of the liquid ahead of the bubble. The velocity of the bubble increases by an amount equal to the maximum velocity in the liquid displaced. For the solutions studied, the induced velocity profile was parabolic and the bubble velocity increase was equal to the liquid velocity at the tube axis, i.e., twice the mean velocity in the liquid displaced. The corrected velocity obtained by subtracting the velocity increase from the value of the bubble velocity is independent of the bubble length.