On the relationship between pipe accelerance and the void fraction of internal two-phase flow

Lannes, Daniel Pontes; Gama, Antonio Lopes

doi:10.1016/j.jfluidstructs.2018.04.005

Cited by 16 publications

(1 citation statement)

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“…In contrast, despite the abundance of applications of U-bends subjected to internal two-phase flow, little research can be found about the vibration of this system. Most of the research on internal two-phase flow focuses on the vibrations of straight pipes (Lannes and Gama (2018)). Nakamura et al (1995) performed experiments with air-water and steam-water flow and concluded that the vibrations in these geometries are closely related to the impact of liquid slugs on the pipes.…”

Section: Introductionmentioning

confidence: 99%

A study of the vibration of a horizontal U-bend subjected to an internal upwards flowing air–water mixture

Moerloose

Degroote

2020

Journal of Fluids and Structures

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U-bends are a common geometry in heat exchangers. In this paper, a U-bend in the vertical plane connected to horizontal straight pipes is considered. An initially stratified water/air flow moves upwards against gravity. The aim of this research is to investigate the internal flow profile and resulting force when the U-bend is subjected to a stratified air-water flow at the inlet. This is done numerically, i.e. by solving the unsteady Reynolds-averaged Navier-Stokes equations. For low mass flow rates, large gas bubbles are naturally formed at the entrance of the bend. The transient force on the tube allows to determine precisely the time instants of bubble initiation and thus to quantify the bubble frequency. Firstly, the tube is assumed to be rigid and the dependence of force oscillation on the inlet conditions is investigated. Secondly, the influence of the viscosity, wall wetting and the mass flow rate is analyzed. Finally, a fluidstructure interaction calculation is performed in order to quantify the vibration characteristics of the tube.

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Section: Introductionmentioning

confidence: 99%