Experimental assessment of local void fraction and flow development in a U-bend piping system for air-water two-phase flow

Kükrer, Ergin; Eskin, Nurdil

doi:10.1016/j.ijmultiphaseflow.2023.104610

Cited by 4 publications

(9 citation statements)

References 54 publications

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“…The bubble diameter at the outlet of the injector is calculated using the relation developed by Kunii and Levenspiel [34] based on the variables, which are the volumetric flow rate and the diameter of the air nozzles. The mean bubble size estimated is 1 mm to 5 mm, as was also investigated in our previous experimental results [10].…”

Section: Mesh Structure and Design Parameterssupporting

confidence: 75%

“…We observed that the bubbles are clustered in the upper portion of the pipe as plugs, exhibiting characteristics indicative of plug flow towards the end of the upstream region. This aspect is further explored in our experimental study [10].…”

Section: Geometry Of Computational Modelmentioning

confidence: 87%

“…Typically, U-bends are constructed solely as 180-degree return bends [25,28,31,32]. However, in our study, we also examine the pre-effect of the 90-degree upward and downward elbows on the two-phase flow, in The dimensions of the model utilized in this study were specifically designed to be consistent with the physical setup outlined in our previously published studies [10,29,30]. The flow domain initiates at the inlet cross-section of a cylindrical pipe with a diameter of D pipe = 40 mm, where two-phase air-water flow conditions are introduced via the circular air injector.…”

Section: Geometry Of Computational Modelmentioning

confidence: 99%

“…In transient simulations, the timestep is set to 1 × 10 −4 s (0.1 ms), which is in line with the experimental acquisition time determined using the Nyquist sampling theorem. Further details on the sampling rate investigation can be found in [10,30]. The simulation is run over an extended flow time, with local two-phase results saved as an output file for each timestep.…”

Section: Numerical Setupmentioning

confidence: 99%

“…In many applications, flow components can have a range of geometries. Multiphase flow can occur in various configurations, including ducts and straight channels [9], U-bends [10,11], manifolds with collectors [12,13], or expansion/contraction sections [14,15]. Industrial flow systems comprise components of varying geometries, leading to singularities and complexities that require comprehensive analysis.…”

Section: Introductionmentioning

confidence: 99%

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Air–Water Two-Phase Flow Dynamics Analysis in Complex U-Bend Systems through Numerical Modeling

Kükrer,

Eskin

2024

Computation

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This study aims to provide insights into the intricate interactions between gas and liquid phases within flow components, which are pivotal in various industrial sectors such as nuclear reactors, oil and gas pipelines, and thermal management systems. Employing the Eulerian–Eulerian approach, our computational model incorporates interphase relations, including drag and non-drag forces, to analyze phase distribution and velocities within a complex U-bend system. Comprising two horizontal-to-vertical bends and one vertical 180-degree elbow, the U-bend system’s behavior concerning bend geometry and airflow rates is scrutinized, highlighting their significant impact on multiphase flow dynamics. The study not only presents a detailed exposition of the numerical modeling techniques tailored for this complex geometry but also discusses the results obtained. Detailed analyses of local void fraction and phase velocities for each phase are provided. Furthermore, experimental validation enhances the reliability of our computational findings, with close agreement observed between computational and experimental results. Overall, the study underscores the efficacy of the Eulerian approach with interphase relations in capturing the complex behavior of the multiphase flow in U-bend systems, offering valuable insights for hydraulic system design and optimization in industrial applications.

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Section: Mesh Structure and Design Parameterssupporting

confidence: 75%

Section: Geometry Of Computational Modelmentioning

confidence: 87%