Numerical study on fluidelastic instability of tube bundles in two-phase flow considering the effect of tube boundary constraint

2020 ◽  
Vol 144 ◽  
pp. 107532 ◽  
Author(s):  
Jiang Lai ◽  
Lei Sun ◽  
Lixia Gao ◽  
Tiancai Tan ◽  
Pengzhou Li
2002 ◽  
Vol 124 (2) ◽  
pp. 144-153 ◽  
Author(s):  
M. J. Pettigrew ◽  
C. E. Taylor ◽  
V. P. Janzen ◽  
T. Whan

The results of a series of tests describing the vibration behavior of several rotated triangular tube bundles subjected to two-phase cross flows are presented. Tube bundles with a pitch-to-diameter ratio of approximately 1.5 were tested over a broad range of void fractions and mass fluxes. Fluidelastic instability, random turbulence excitation, hydrodynamic mass, two-phase damping and local void-fraction were investigated. Well-defined fluidelastic instabilities were observed in continuous two-phase flow regimes. However, intermittent two-phase flow regimes had a dramatic effect on fluidelastic instability leading to lower than expected threshold flow velocities for instability. This effect was more pronounced in Freon two-phase flow than in air-water, and appeared well correlated to the transition between continuous and intermittent flow regimes. Generally, random turbulence excitation forces were much lower in Freon than in air-water. Although very dependent on void fraction, as expected, damping was quite similar in air-water and Freon.


2021 ◽  
pp. 219-269
Author(s):  
Michel J. Pettigrew ◽  
Colette E. Taylor

2020 ◽  
Vol 144 ◽  
pp. 107530 ◽  
Author(s):  
Jiang Lai ◽  
Dan Zhang ◽  
Lei Sun ◽  
Lixia Gao ◽  
Tiancai Tan ◽  
...  

2011 ◽  
Vol 54 (9) ◽  
pp. 2412-2420 ◽  
Author(s):  
ZhaoQin Huang ◽  
Jun Yao ◽  
YueYing Wang ◽  
Ke Tao

2021 ◽  
Vol 321 ◽  
pp. 01002
Author(s):  
Claire Dubot ◽  
Vincent Melot ◽  
Claudine Béghein ◽  
Cyrille Allery ◽  
Clément Bonneau

Being able to predict the void fraction is essential for a numerical prediction of the thermohydraulic behaviour in steam generators. Indeed, it determines two-phase mixture density and affects two-phase mixture velocity which enable to evaluate the pressure drop of heat exchanger, the mass transfer and heat transfer coefficients. In this study, the flow is modelled by coupling Ansys Fluent with an in-house code library where a CFD porous media approach is implemented. In this code, the two-phase flow has been modelled so far using the Eulerian model. However, this two-phase model requires interaction laws between phases which are not known and/or reliable for a flow within a tube bundle. The aim of this paper is to use the mixture model, for which it is easier to implement suitable correlations for tube bundles. By expressing the relative velocity, as a function of slip, the void fraction model of Feenstra et al. developed for upward cross-flow through horizontal tube bundles is introduced. With this method, physical phenomena that occur in tube bundles are taken into consideration in the mixture model. The developed approach is validated based on the experimental results obtained by Dowlati et al.


2005 ◽  
Vol 4 (2) ◽  
Author(s):  
G. Ribatskia ◽  
J. R. Thome

This paper presents a state-of-the-art review of the hydrodynamic aspects of two-phase flow across horizontal tube bundles. The review covers studies related to the evaluation of void fraction, two-phase flow behaviors and pressure drops on the shell side of staggered and in-line tube bundles for upward, downward and side-to-side flows. This study of the literature critically describes the proposed flow pattern maps and semi-empirical correlations for predicting void fraction and frictional pressure drop. These predicting methods are generally based on experimental results for adiabatic air-water flows. A limited number of experimental studies with R-11 and R-113 were also carried out in the past. The review shows noticeable discrepancies among the available prediction methods. Finally, this study suggests that further research focusing on the development of representative databanks and new prediction methods is still necessary.


Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 330 ◽  
Author(s):  
Chuan Wang ◽  
Bo Hu ◽  
Yong Zhu ◽  
Xiuli Wang ◽  
Can Luo ◽  
...  

A self-priming centrifugal pump can be used in various areas such as agricultural irrigation, urban greening, and building water-supply. In order to simulate the gas-water two-phase flow in the self-priming process of a self-priming centrifugal pump, the unsteady numerical calculation of a typical self-priming centrifugal pump was performed using the ANSYS Computational Fluid X (ANSYS CFX) software. It was found that the whole self-priming process of a self-priming pump can be divided into three stages: the initial self-priming stage, the middle self-priming stage, and the final self-priming stage. Moreover, the self-priming time of the initial and final self-priming stages accounts for a small percentage of the whole self-priming process, while the middle self-priming stage is the main stage in the self-priming process and further determines the length of the self-priming time.


2020 ◽  
Vol 191 ◽  
pp. 107173 ◽  
Author(s):  
Jiaqiang Jing ◽  
Mingjun Du ◽  
Ran Yin ◽  
Yahui Wang ◽  
Yu Teng

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