scholarly journals Vortex in Cell Method for Gas-Liquid Two-Phase Free Turbulent Flow (Numerical Method and Application to Bubbly Flow around a Square-Section Cylinder)

2006 ◽  
Vol 72 (718) ◽  
pp. 1418-1425 ◽  
Author(s):  
Tomomi UCHIYAMA ◽  
Temohiro DEGAWA
Keyword(s):  
Turbulent Flow ◽  
Numerical Method ◽  
Bubbly Flow ◽  
Two Phase ◽  
Cell Method ◽  
Free Turbulent Flow

A Numerical Method for the Analysis of a New Model for Two-Phase Bubbly Flow in Elastic Pipes

2002 ◽  
Author(s):  
D. Kim
Keyword(s):  
Numerical Method ◽  
Surface Deformation ◽  
Two Phase Flow ◽  
Numerical Technique ◽  
Bubbly Flow ◽  
Neumann Boundary ◽  
Phase Flow ◽  
Two Phase ◽  
Tube Cross Section ◽  
Elastic Pipes

A new approach and numerical method for study gas-liquid two-phase flows in elastic pipes is suggested. “A nonlinear wave dynamical model for liquid containing gas bubbles” is applied to derive governing equations for two-phase flow-filled pipelines. On assuming the hydraulic approximation the continuity and momentum equations of two-phase flow in a pipe are obtained for the first time. From these equations the inhomogeneous wave equation of Lighthill-type for two-phase flow in pipelines is derived. The shear stress at the tube surface, deformation of the tube cross-section, and liquid’s phase compressibility are taken into account. A high effectively and accurate finite difference technique for the exact solution of the basic equations in the case of Neumann boundary conditions is developed. Based on the proposed algorithm various numerical experiments have been carried out to investigate the major fluid dynamical features of hydraulic shocks and shock waves in the horizontal pipes. Comparisons with both the experimental data and computational results obtained with a second-order accurate predictor-corrector method support our numerical technique as well as the model.

Experimental Study of the Sub-Channel Flow Regimes in 5×5 Rod Bundles With Simplified Grid Spacer

2017 ◽  
Author(s):  
Quanyao Ren ◽  
Wenxiong Zhou ◽  
Liangming Pan ◽  
Hang Liu ◽  
Bin Yu ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Flow Regime ◽  
Cross Section ◽  
Channel Flow ◽  
Two Phase Flow ◽  
Bubbly Flow ◽  
Flow Regimes ◽  
Phase Flow ◽  
Rod Bundles ◽  
Two Phase

Traditionally, the flow regime in two phase flow in rod bundles are considered in a global sense by the visualization. However, a sub-channel flow regime is required to understand and model the two phase flow structures in rod bundles. In this work, a sub-channel impedance meter was designed to get the dynamic feature in the sub-channels, which was applied to identify the sub-channel flow regime by the fast search and finding peaks of the cumulative probability distribution functions (CPDFs) objectively. In the present study, five flow regimes, namely bubbly flow, quasi-cap bubbly flow, quasi-slug flow, cap-turbulent flow and churn-turbulent flow were defined and recognized. The sub-channel flow regimes at the same cross section were compared to each other, which show similar feature with the local flow regimes in pipe. It is possible to identify nine different global flow regime configurations by combining the corner, side and inner sub-channel flow regime at the same cross section, which was drawn in the 2D sub-channel flow regime.

Numerical simulation of annular bubble plume by vortex in cell method

2019 ◽  
Vol 29 (3) ◽  
pp. 1103-1131 ◽  
Author(s):  
Van Luc Nguyen ◽  
Tomohiro Degawa ◽  
Tomomi Uchiyama
Keyword(s):  
Vortex Structure ◽  
Bubble Dynamics ◽  
Bubbly Flow ◽  
Flow Characteristics ◽  
Lagrangian Description ◽  
Bubble Plume ◽  
Two Phase ◽  
Buoyant Force ◽  
Content Type ◽  
Cell Method

PurposeThis study aims to provide discussions of the numerical method and the bubbly flow characteristics of an annular bubble plume.Design/methodology/approachThe bubbles, released from the annulus located at the bottom of the domain, rise owing to buoyant force. These released bubbles have diameters of 0.15–0.25 mm and satisfy the bubble flow rate of 4.1 mm3/s. The evolution of the three-dimensional annular bubble plume is numerically simulated using the semi-Lagrangian–Lagrangian (semi-L–L) approach. The approach is composed of a vortex-in-cell method for the liquid phase and a Lagrangian description of the gas phase.FindingsFirst, a new phenomenon of fluid dynamics was discovered. The bubbly flow enters a transition state with the meandering motion of the bubble plume after the early stable stage. A vortex structure in the form of vortex rings is formed because of the inhomogeneous bubble distribution and the fluid-surface effects. The vortex structure of the flow deforms as three-dimensionality appears in the flow before the flow fully develops. Second, the superior abilities of the semi-L–L approach to analyze the vortex structure of the flow and supply physical details of bubble dynamics were demonstrated in this investigation.Originality/valueThe semi-L–L approach is applied to the simulation of the gas–liquid two-phase flows.

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