Abstract The stagnant Taylor bubble in vertical isothermal turbulent counter-current flow was analyzed using 2D shadowgraphy experiments and two distinct high-fidelity numerical simulations. One simulation employed the geometrical VOF interface tracking method within the OpenFOAM code, while the other utilized the explicit front tracking method of the TrioCFD code. Interface recognition algorithms were applied to the photographs and compared with the results of 3D simulations performed with LES and pseudo-DNS accuracy in OpenFOAM and TrioCFD, respectively. The measured Taylor bubbles exhibited an asymmetric bullet-train shape and a specific speed, which were compared with the predictions of both numerical approaches. Reproducing the experiment proved challenging for both otherwise well-established methods frequently used in interface tracking simulations of two-phase flows. Grid resolution and subgrid turbulent models, known for their success in single-phase turbulence, were less accurate near the water–air interface. Additional experimental parameters compared with simulations were related to the dynamics of tiny disturbance waves with amplitudes ranging from 10 to 100 µm along the interface of the Taylor bubbles. The speed and spectra of the surface disturbance waves were reproduced numerically with moderate success despite detailed grid refinement in the relevant region of the computational domain.

Shadowgraphy

Tracking (education)

10.1007/s13369-024-09489-2

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Citations (1)

Validating RANS to predict the flow behavior in wire-wrapped fuel assemblies

Nuclear Engineering and Design (2019)

D. Dovizio Blaž Mikuž Afaque Shams F. Roelofs

Liquid metal

10.1016/j.nucengdes.2019.110376

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Citations (28)

Experimental Study of Stagnant Taylor Bubble in Counter-Current Flow

Iztok Tiselj Jan Kren Blaž Mikuž

10.13182/nureth20-40768

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Numerical study of Taylor bubble breakup in counter-current flow using large eddy simulation

Physics of Fluids (2024)

Jan Kren E.M.A. Frederix Iztok Tiselj Blaž Mikuž

This paper investigates dynamics of Taylor bubble in counter-current flows, leveraging large eddy simulations combined with the volume of fluid method. Utilizing the OpenFOAM framework, we have implemented a high-order Runge–Kutta time-integration scheme, along with a piecewise linear interface calculation method for precise geometric reconstruction of the bubble interface. We examine the performance of algebraic vs geometric capturing techniques in the context of Taylor bubble breakup, focusing specifically on the transitional flow regime with a liquid Reynolds number of 1400. Our results reveal that the geometric capturing technique offers superior accuracy, improving our understanding of the breakup process and providing valuable insight for multiphase flow simulations in various engineering fields. Our study also reveals the emergence of a secondary vortex in the turbulent wake region behind the Taylor bubble, a phenomenon most prominent at finer mesh resolutions. This vortex represents a novel discovery in counter-current Taylor bubble flows.

Large-Eddy Simulation

Taylor microscale

10.1063/5.0186236

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Building a unique test section for local critical heat flux studies in light water reactor like accident conditions

Marko Matkovič Leon Cizelj Ivo Kljenak Boštjan Končar Blaž Mikuž

Light-water reactor

Section (typography)

Source

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Citations (1)