Numerical investigation of the mechanism of two-phase flow instability in parallel narrow channels

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.

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Parametric analysis of two-phase flow instability in a channel with inlet and outlet hydraulic resistances

Journal of Applied Mechanics and Technical Physics ◽

10.1007/bf02467995 ◽

1998 ◽

Vol 39 (1) ◽

pp. 41-46

Author(s):

A. B. Shigarov

Keyword(s):

Parametric Analysis ◽

Two Phase Flow ◽

Flow Instability ◽

Phase Flow ◽

Two Phase

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Numerical investigation of two-phase flow in anisotropic porous evaporator

International Journal of Thermal Sciences ◽

10.1016/j.ijthermalsci.2018.08.026 ◽

2019 ◽

Vol 135 ◽

pp. 1-16 ◽

Cited By ~ 12

Author(s):

Omar Rafae Alomar ◽

Rafie Rushdy Mohammed ◽

Miguel A.A. Mendes ◽

Subhashis Ray ◽

Dimosthenis Trimis

Keyword(s):

Numerical Investigation ◽

Two Phase Flow ◽

Phase Flow ◽

Two Phase

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

Science and Technology of Nuclear Installations ◽

10.1155/2019/2045751 ◽

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.

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