Experimental Investigations and Numerical Assessment of Liquid Velocity Profiles and Turbulence for Single- and Two-phase Flow in a Constricted Vertical Pipe

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Contributors

Abstract

In this work, the capabilities of state-of-the-art turbulence models are compared for a three-dimensional flow (3D) field within a constricted vertical pipe. The considered flow domain is a vertical pipe section with a baffle-shaped flow constriction which leads to the development of a jet flow through and a recirculation flow region behind the constriction. Different Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) models were tested for single- and two-phase flow simulations. In the two-phase simulations, bubble-induced turbulence (BIT) was also considered by adding source terms in the k and ε/ω equations. The results are validated against experimental data. We employed hot-film anemometry (HFA) for liquid velocity measurement and combined it with ultrafast X-ray computed tomography (UFXCT), which provides gas phase data. Based on the local phase-indicator function obtained from the tomographic image data, we can correct HFA signals, which become corrupted by bubble contacts. We found that for single-phase flow all RANS models predict axial velocity well while radial velocity prediction is inadequate. LES models, however, achieve a better prediction of the latter. For two-phase flow, the axial component of the liquid velocity is well captured by all RANS models and the radial component of the liquid velocity is predicted better than for single-phase flow. In general, the computationally less costly RNG k-ε model performs similar to the SSG RSM model and can therefore be recommended for simulation of complex flow scenarios.

Details

Original languageEnglish
Article number104224
JournalInternational journal of multiphase flow
Volume157
Publication statusPublished - Dec 2022
Peer-reviewedYes

External IDs

ORCID /0000-0001-9264-5129/work/173054097

Keywords

Keywords

  • Bubbly two-phase flow, CFD modelling, Computed tomography, Hot-film anemometry, Liquid velocity, Turbulent kinetic energy