Research on two-phase flow instability in parallel rectangular channels

2014 ◽  
Vol 65 ◽  
pp. 47-59 ◽  
Author(s):  
Libo Qian ◽  
Shuhua Ding ◽  
Suizheng Qiu
Keyword(s):  
Two Phase Flow ◽  
Flow Instability ◽  
Phase Flow ◽  
Two Phase ◽  
Rectangular Channels

Experimental study of two phase flow instability in parallel narrow rectangular channels

2012 ◽  
Vol 50 ◽  
pp. 103-110 ◽  
Author(s):  
Zhou Yuan ◽  
Yan Xiao ◽  
Wang Yanlin ◽  
Liu Yanjun ◽  
Huang Yanping
Keyword(s):  
Experimental Study ◽  
Two Phase Flow ◽  
Flow Instability ◽  
Phase Flow ◽  
Two Phase ◽  
Rectangular Channels

Research on Two-Phase Flow Instability in Parallel Multi-Channel Under Rolling Motion Condition

2008 ◽  
Author(s):  
Y. J. Zhang ◽  
G. H. Su ◽  
S. Z. Qiu ◽  
X. B. Yang
Keyword(s):  
Two Phase Flow ◽  
Flow Instability ◽  
Stability Boundary ◽  
Channel Number ◽  
Rolling Motion ◽  
Phase Flow ◽  
Two Phase ◽  
Channel System ◽  
Motion Condition ◽  
High Equilibrium

Two-phase flow instability of the parallel multi-channel system has been studied under rolling motion condition in this paper. Based on the homogeneous flow model with considering the rolling motion condition, the parallel multi-channel model is established by using the control volume integrating method. Gear method is used to solve the system equations. The influences of the inlet and upward sections and the heating power on the flow instability under rolling motion condition have been analyzed. The marginal stability boundary (MSB) under rolling motion condition is obtained and the unstable regions occur in both low and high equilibrium quality regions. The region with low inlet subcooling is also instable. In high equilibrium quality region, the multiplied period phenomenon is found and the chaotic phenomenon appears at the MSB. The oscillation part of mass flow rate (amplitude) may be averaged into other channels so that the influence of rolling motion is weakened. But the stability of multi-channel system is independent of the channel number and the increase of the channel number could only make the amplitude more uniformity in channels.

scholarly journals Numerical Study of Bubble Rising and Coalescence Characteristics under Flow Pulsation Based on Particle Method

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Ronghua Chen ◽  
Minghao Zhang ◽  
Kailun Guo ◽  
Dawei Zhao ◽  
Wenxi Tian ◽  
...  
Keyword(s):  
Flow Rate ◽  
Two Phase Flow ◽  
Flow Instability ◽  
Numerical Study ◽  
Phase Flow ◽  
Flow Pulsation ◽  
Two Phase ◽  
Inlet Flow ◽  
Inlet Flow Rate ◽  
Bubble Rising

Two-phase flow instability may occur in nuclear reactor systems, which is often accompanied by periodic fluctuation in fluid flow rate. In this study, bubble rising and coalescence characteristics under inlet flow pulsation condition are analyzed based on the MPS-MAFL method. To begin with, the single bubble rising behavior under flow pulsation condition was simulated. The simulation results show that the bubble shape and rising velocity fluctuate periodically as same as the inlet flow rate. Additionally, the bubble pairs’ coalescence behavior under flow pulsation condition was simulated and compared with static condition results. It is found that the coalescence time of bubble pairs slightly increased under the pulsation condition, and then the bubbles will continue to pulsate with almost the same period as the inlet flow rate after coalescence. In view of these facts, this study could offer theory support and method basis to a better understanding of the two-phase flow configuration under flow pulsation condition.

The influence of non-uniform heating on two-phase flow instability in subchannel

2019 ◽  
Vol 345 ◽  
pp. 7-14
Author(s):  
Sipeng Wang ◽  
Bao-Wen Yang ◽  
Hu Mao ◽  
Yu-chen Lin ◽  
Guanyi Wang
Keyword(s):  
Two Phase Flow ◽  
Flow Instability ◽  
Phase Flow ◽  
Uniform Heating ◽  
Two Phase

scholarly journals A Unifying Numerical Framework for the “Small-Slope” Based Core-Annular Flow Instability Models

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1941
Author(s):  
Antonio Quevedo ◽  
Carlos Fuentes ◽  
Carlos Chávez ◽  
Enrique González-Sosa ◽  
Carlos Mota
Keyword(s):  
Evolution Equations ◽  
Two Phase Flow ◽  
Flow Instability ◽  
Nonlinear Partial Differential Equations ◽  
Mass Conservation ◽  
Flow In Porous Media ◽  
Phase Flow ◽  
Two Phase ◽  
Theoretical Approaches ◽  
Highly Nonlinear

The snap-off is an instability phenomenon that takes place during the immiscible two-phase flow in porous media due to competing forces acting on the fluid phases and at the interface between them. Different theoretical approaches have been proposed for the development of mathematical models that describe the dynamics of a fluid/fluid interface in order to analyze the snap-off mechanism. The models studied here are based on the “small-slope” approach and were derived from the mass conservation and other governing equations of two-phase flow at pore scale in circular capillaries for pure and complex interfaces. The models consist of evolution equations; highly nonlinear partial differential equations of fourth order in space and first order in time. Although the structure of the models for each type of interface is similar, different numerical techniques have been employed to solve them. Here, we propose a unifying numerical framework to solve the group of such models. Such a framework is based on the Fourier pseudo-spectral differentiation method which uses the Fast Fourier Transform (FFT) and the inverse FFT (IFFT) algorithms. We compared the solutions obtained with this method to the results reported in the literature in order to validate our framework. In general, acceptable agreements were obtained in the dynamics of the snap-off.

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