Annular Two-Phase Flow—Part 2: Additional Effects

1970 ◽  
Vol 92 (1) ◽  
pp. 73-81 ◽  
Author(s):  
G. B. Wallis
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Liquid Film ◽  
Relative Velocity ◽  
Two Phase Flow ◽  
Reynolds Numbers ◽  
Shear Stress Distribution ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Part

The theory of Part 1 is modified by taking additional phenomena into account. The liquid film, the gas core, and the interface are considered separately. The effects of entrainment, compressibility, liquid and gas Reynolds numbers, shear-stress distribution, relative velocity, and the various types of interfacial waves are discussed.

An Experimental Study on Liquid Film Dynamics and Interfacial Wave of Air-Water Two-Phase Flow in a Horizontal Channel

2013 ◽  
Author(s):  
Youjia Zhang ◽  
Weimin Ma ◽  
Shengjie Gong
Keyword(s):  
Liquid Film ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Research Work ◽  
Water Film ◽  
Test Facility ◽  
Phase Flow ◽  
Interfacial Wave ◽  
Film Rupture ◽  
Two Phase

This study is concerned with liquid film dynamics and stability of annular flow, which plays an important role in understanding film rupture and dryout in boiling heat transfer. The research work starts from designing and making a test facility which enables the visualization and measurement of liquid film dynamics. A confocal optical sensor is applied to track the evolution of film thickness. A horizontal rectangular channel made of glass is used as the test section. Deionized water and air are supplied into that channel in such a way that an initial stratified flow forms, with the liquid film on the bottom wall. The present study is focused on characterization of liquid film profile and dynamics in term of interfacial wave and shear force induced film rupture under adiabatic condition. Based on the experimental data and analysis, it is found that given a constant water flowrate, the average thickness of water film decreases with increasing air flowrate, while the interfacial wave of the two-phase flow is intensified. As the air flowrate reaches a critical value, a localized rupture of the water film occurs.

scholarly journals Hydrodynamic Modeling of Turbulence Modulation by Particles in Swirling Gas-Particle Two-Phase Flow

2021 ◽  
Author(s):  
Yang Liu ◽  
Lixing Zhou
Keyword(s):  
Shear Stress ◽  
Two Phase Flow ◽  
Heavy Particle ◽  
Light Particle ◽  
Particle Collision ◽  
Order Moment ◽  
Enhancement Effect ◽  
Phase Flow ◽  
Primary Role ◽  
Two Phase

Abstract Turbulence modulations by particles of swirling gas-particle two-phase flow the axisymmetric chamber is investigated. To fully consider the preferential concentrations and anisotropic dispersions of particle, a second-order moment model coupling particle-particle collision model was improved based on the Eulerian-Eulerian two-fluid approach and the kinetic theory of granular flow. Proposed model, algorithm and in-house codes are validated and they are in good agreement with the experiment. Effects of ultralight expanded graphite and heavy Copper particles with large spans of Stokes number on gas velocity and fluctuations, Reynolds shear stress and tensor invariants, turbulence kinetic energy, and vortices structures are numerically simulated. Results show turbulent modulation exhibits strongly anisotropic characteristics and keeps in close relationship with flow structure. The disturbances of modulations, the alternations of vortex evolution are enforced by heavy-large particle with higher Stokes numbers. Preferential accumulations of light particle at shear stress regions in low vortices are weaker than those of heavy particle. For axial turbulence modulations, heavy particle plays the primary role on inhibition action due to larger inertia and light particle contributes to enhancement effect due to excellent followability.

scholarly journals CFD modeling of liquid film reversal of two-phase flow in vertical pipes

2019 ◽  
Vol 9 (4) ◽  
pp. 3039-3070
Author(s):  
Mohamed M. Hussein ◽  
A. Al-Sarkhi ◽  
H. M. Badr ◽  
M. A. Habib
Keyword(s):  
Liquid Film ◽  
Two Phase Flow ◽  
Cfd Modeling ◽  
Phase Flow ◽  
Two Phase

Numerical Calculation of Shear Stress Distribution on the Inner Wall Surface of CANDU Reactor Feeder Pipe Conveying Two-Phase Coolant

2007 ◽  
Author(s):  
Jong Chull Jo ◽  
Dong Gu Kang ◽  
Kyung Wan Roh
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Wall Thickness ◽  
Shear Stress Distribution ◽  
Cfd Analysis ◽  
Two Phase ◽  
Accelerated Corrosion ◽  
Wall Thinning ◽  
Local Areas ◽  
Flow Accelerated Corrosion

Two-phase flow fields inside feeder pipes of a CANDU reactor have been simulated numerically using a CFD (computational fluid dynamics) code to calculate the shear stress distribution which is the most important factor to be considered in predicting the local areas of feeder pipes highly susceptible to FAC (flow-accelerated corrosion)-induced wall thinning. The CFD approach with schemes used in this study to simulate the turbulent flow situations inside the CANDU feeder pipes had been verified by showing a good agreement between the investigation results for the failed feedwater pipe at Surry Unit 2 plant in U.S. and the CFD calculation. Sensitivity studies of the three geometrical parameters such as angle of the 1st and 2nd bends, length of the 1st span between the grayloc hub and the 1st bend, and length of the 2nd span between the 1st and the 2nd bends had already been performed. In this study, the effects of void fraction of the primary coolant coming out from the exit of pressure tubes containing nuclear fuels on the fluid shear stress distribution at the inner surface of feeder pipe wall have been investigated to find out the local areas of feeder pipes conveying two-phase coolant, where are highly susceptible to FAC (flow-accelerated corrosion)-induced wall thinning. As the results of CFD analysis, it is seen that the local regions of feeder pipes of the operating CANDU reactors in Korea, on which the wall thickness measurements have been performed so far, are not coincided with the worst regions predicted by the present CFD analysis where is the connection region of straight & bend pipe near the inlet part of the bend intrados. Finally, based on the results of the present CFD analysis a guide to the selection of the weakest local positions where the measurement of wall thickness should be performed with higher priority has been provided.

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