On the turbulent structure in the wake of Taylor bubbles rising in vertical pipes

Abstract

The development of gas-liquid slug flow along pipes is governed by the interaction between consecutive elongated bubbles. It is commonly accepted that the trailing bubble's shape and velocity are affected by the flow field in the liquid phase ahead of it. Particle image velocimetry ͑PIV͒ measurements of the velocity field in the wake of an elongated Taylor bubble are performed for different pipe diameters and various Reynolds numbers. Experiments are carried out in both laminar and turbulent background flows. Ensemble-averaged quantities in the frame of reference moving with the Taylor bubble are calculated. Peculiarities regarding the variation of the mean velocity distributions, as well as of the normal and shear Reynolds stresses, with the distance from the Taylor bubble bottom are discussed.

Bubble characterization in horizontal air–water intermittent flow

“…This work was motivated by the recent availability of high frame rate cameras that, combined with techniques for image analysis, added new possibilities to address the problem. The combination of these techniques have been used to investigate two-phase flows in several works, such as (Polonsky et al, 1999;Nogueira et al, 2003;Ursenbacher, 2004;Shemer et al, 2007;Mayor et al, 2007;Guo et al, 2010). The non-intrusive nature of these techniques make them suitable for studying flow regimes sensitive to disturbances, such as plug, slug and annular flows.…”

Experimental study on near wall transport characteristics of slug flow in a vertical pipe

“…The study was extended by Shemer et al [6] to include Taylor bubbles rising in laminar and turbulent background flows. PIV measurements of the velocity field in the wake of an elongated Taylor bubble were performed by Shemer et al [7] for different pipe diameters and various Reynolds numbers.…”

Movement of Two Consecutive Taylor Bubbles in Vertical Pipes

“…Away from the near-wake region, the variation of the mean axial liquid velocity along the pipe, where the velocity attains its maximum value within a given cross section, is of particular importance. The detailed information on the mean velocity field in the wake of a single Taylor bubble accumulated in experiments carried out in the present facility is presented elsewhere (Shemer et al 2007). This data on the mean and instantaneous velocity field in the Taylor bubble wake is now applied to study the propagation of the trailing Taylor bubble.…”

“…The accuracy of the local instantaneous PIV velocity measurements for the operational conditions of the present study was estimated to be better that 1 mm/s. For more details about the experimental facility and PIV measurements, see van Hout et al (2002) and Shemer et al (2007).…”

“…The liquid velocity in the film is usually several times larger than the mean velocity of the liquid in the slug, forming a circumferential wall jet. The velocity field in the wake of the Taylor bubble is complicated and has been subject to numerous investigations (van Hout et al 2002, Shemer et al 2005, 2007.…”