Experimental Study on the Interfacial Evolution of Taylor Bubble at Inception of an Annulus

Abstract

This present work reports results of an experimental campaign in a 20 mm internal diameter tube to comprehend the interfacial evolution of a fully developed Taylor bubble to an annular bubble at the inception of an annulus. The phenomenon has been observed by using a high speed photography camera and has been further analyzed by using image processing tools. Interfacial evolution is found to be a complex phenomenon with various physics rich processes occurring simultaneously in six stages, namely, retardation of fully developed Taylor bubble, plateau formation, doughnut shape formation and nucleation of lobes, preferential rise of leading lobe and retraction of lagging lobe, thread formation of lagging lobe, and finally, manifestation of an annular bubble. Effects of fluid viscosity and eccentricity on hydrodynamics features, such as annular bubble rise velocity, film thickness, nose shape, and reacceleration of the annular bubble are investigated in detail.

Development of closure relations for the motion of Taylor bubbles in vertical and inclined annular pipes using high-fidelity numerical modeling

“…6 In recent years, a number of investigations have sought to provide insight into these bubbles in tubular pipes, 5,[7][8][9][10] but the understanding of their behavior in annular conduits is still limited. 11,12 The importance of this piping configuration has increased, for example, with the unconventional extraction techniques used to maintain supply of natural gas among the depletion of conventional reservoirs. 13 Determining the pressure gradient through conduits in the presence of multiphase flow is often addressed using empirical and/or mechanistic models.…”

Development of a multiphase lattice Boltzmann model for high-density and viscosity ratio flows in unconventional gas wells

“…In comparison to the body of literature available on Taylor bubbles in tubular conduits, research into the dynamics associated with flow in an annulus is limited [226,227]. The primary variation between the two flow confinements comes from the shape of the bubble nose that develops and the breakdown of symmetry observed in the annular configuration.…”

“…Due to the potential flow techniques employed in the early stages of Taylor bubble analysis, understanding the shape and governing forces in these different bubble regions became critical to the analysis. A limited number of studies look to investigate this problem in detail, with recent investigations by the likes of Rohilla and Das [227], finding novel conclusions about the nature of the annular Taylor bubble shape. From the previous chapter, it is clear that high resolution data is obtainable with the proposed PFLBM, and as such the aim of this chapter is to demonstrate the capability of the model and present a methodology for which the behaviour of Taylor bubbles can be further understood.…”

“…They were able to determine correction terms for small, D 2 ≤ 0.0254 m, and large, D 2 ≥ 0.247 m, pipe configurations, with which accurate predictions were obtained for their own and existing experimental data in the literature. From this study, the rise velocity of a Taylor bubble in pipe sizing applicable to natural gas wells can be predicted as, = 0.322 × 0.765 g(D 1 + D 2 ) , D 2 ≤ 0.0254 m u T B = 0.323 g(D 1 + D 2 ) , 0.0254 m < D 2 < 0.247 m.This correlation was further validated by Agarwal et al[228], where it was used to make conclusions about the practicality of extending the analysis from a circular annulus to a square shaped conduit.Rohilla and Das[227] more recently made use of it when analysing the effects of eccentricity as well as investigating the transition from a tubular to annular Taylor bubble as it passed over a cylindrical insert. These few findings represent the main body of research existing for annular Taylor bubbles, "despite being a widely observed phenomenon"[227].…”

“…The methodology applied for these three simulations provides a means with which one can analyse Taylor bubble dynamics in vertical annular pipes. This could replace the use of physical experiments in correlating dimensionless flow parameters with the bubble rise behaviour, and as such gives a potential method for developing a unified rise velocity correlation.7.3 Effect of pipe inclinationWith the limited literature available on the flow of Taylor bubbles in annular piping[226,227], it is not surprising that their flow in inclined annuli is also remiss. The general problem of two-phase flow in a deviated annulus has seen more focused research interest in the past than the particulars of the slug flow regime.…”