scholarly journals Determination of gas & liquid two-phase flow regime transitions in wellbore annulus by virtual mass force coefficient when gas cut

2017 ◽  
Author(s):  
Junbo Qu ◽  
Tie Yan ◽  
Xiaofeng Sun ◽  
Ye Chen ◽  
Yi Pan
Keyword(s):  
Flow Regime ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Mass Force ◽  
Virtual Mass ◽  
Force Coefficient ◽  
Two Phase ◽  
Regime Transitions

Evaluation of Length Scales and Meshing Requirements for Resolving Two-Phase Flow Regime Transitions Using the Level Set Method

2021 ◽  
Author(s):  
Matt Zimmer ◽  
Igor A Bolotnov
Keyword(s):  
Thin Films ◽  
Flow Regime ◽  
Level Set Method ◽  
Level Set ◽  
Two Phase Flow ◽  
Small Scale ◽  
Phase Flow ◽  
Two Phase ◽  
Interface Capturing ◽  
Regime Transitions

Abstract New criteria for fully resolving two-phase flow regime transitions using direct numerical simulation with the level set method for interface capturing are proposed. A series of flows chosen to capture small scale interface phenomena are simulated at different grid refinements. These cases include droplet deformation and breakup in a simple shear field, the thin film around a Taylor bubble, and the rise of a bubble towards a free surface. These cases cover the major small scale phenomena observed in two-phase flows: internal recirculation, interface curvature, interface snapping, flow of liquid in thin films, and drainage/snapping of thin films. The results from these simulations and their associated grid studies were used to develop new meshing requirements for simulation of two-phase flow using interface capturing methods, in particular the level set method. When applicable, the code used in this work, PHASTA, was compared to experiments in order to contribute to the ongoing validation process of the code. Results show that when the solver meets these criteria, with the exception of resolving the nanometer scale liquid film between coalescing bubbles, the code is capable of accurately simulating interface topology changes.

Visualization of Flow Regime Transitions in Two-Phase Flow Under High Voltage Electric Fields

2006 ◽  
Author(s):  
Hossam S. Sadek ◽  
James S. Cotton ◽  
Chan Y. Ching ◽  
Mamdouh Shoukri
Keyword(s):  
Flow Regime ◽  
Electric Fields ◽  
High Voltage ◽  
High Speed ◽  
Two Phase Flow ◽  
Quartz Tube ◽  
Phase Flow ◽  
Interfacial Instabilities ◽  
Two Phase ◽  
Regime Transitions

The effects of applying DC high voltage electric fields on two-phase flow regime transitions for flowing refrigerant HFC-134a were visualized using a high speed camera. The viewing test section was made of 10 mm inner diameter quartz tube with a 3.18 mm diameter charged electrode placed along the center of the tube. The quartz tube was coated with an electrically grounded transparent conductive film of Tin Oxide. The experiments were performed for mass flux (55 kg/m2s < G < 263 kg/m2s), quality (20% < x < 80%) and applied voltage (0 kV < V < 8 kV). The flow regime transitions depend on the flow regime prior to applying the EHD. For stratified flow, EHD increases the interfacial instabilities and causes liquid extraction to the upper section of the tube. When the flow regime is initially annular flow, EHD increases the uniformity of the annular film by extracting liquid from the thicker liquid regions into the vapor core.

scholarly journals Effects of System Pressure on Flow Regime Transitions in Vertical Upward Gas-Liquid Two-Phase Flow.

1993 ◽  
Vol 59 (568) ◽  
pp. 3883-3890
Author(s):  
Masao Nakazatomi ◽  
Hideo Shimizu ◽  
Tsumoru Ochiai ◽  
Kotohiko Sekoguchi
Keyword(s):  
Flow Regime ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
System Pressure ◽  
Regime Transitions

DIFFUSIONAL ANALYSIS OF INTERMITTENT TWO-PHASE FLOW TRANSITIONS

Fractals ◽  
1994 ◽  
Vol 02 (02) ◽  
pp. 265-268 ◽  
Author(s):  
MASSIMILIANO GIONA ◽  
ALESSANDRO PAGLIANTI ◽  
ALFREDO SOLDATI
Keyword(s):  
Flow Regime ◽  
Two Phase Flow ◽  
Mean Square Displacement ◽  
Density Fluctuations ◽  
Intermittent Flow ◽  
Scaling Analysis ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Transitions ◽  
Regime Transitions

Diffusional analysis is employed to characterize two-phase flow regime transitions in horizontal pipes. The scaling analysis of the mean square displacement [Formula: see text] associated with the diffusional process driven by density fluctuations proves to be an efficient method for two-phase regime identification. Intermittent flow regime transitions are discussed and compared with theoretical and semiempirical models.

Cryogenic Two-Phase Flow During Chilldown

Volume 3 ◽  
2004 ◽  
Author(s):  
Christopher Velat ◽  
Jelliffe Jackson ◽  
James F. Klausner ◽  
Renwei Mei
Keyword(s):  
Film Thickness ◽  
Flow Regime ◽  
High Velocity ◽  
Test Section ◽  
Two Phase Flow ◽  
Nucleate Boiling ◽  
Film Boiling ◽  
Phase Flow ◽  
Two Phase ◽  
Regime Transitions

This work describes an experimental investigation of the transient two-phase flow behavior of liquid nitrogen flowing through a pipeline during the chilldown process. The evaporation process and flow regime transitions were observed during chilldown. Initially pure vapor is observed in the visual test section. Then a moving film boiling front is observed to move through the test section. The length of the film boiling front appears to be very small compared with the length of the facility pipeline. After the film boiling front passes through the test section, a very high velocity stratified two-phase flow appears with a small liquid film thickness. As the pipeline is chilled, the film thickness grows. It appears that the high velocity two-phase flow suppresses nucleate boiling, and the dominant heat transfer mechanism is two-phase bulk turbulent convection. Evaporation occurs at the liquid/vapor interface. A high-speed video camera is used to observe the flow regime transitions during the transient chilldown process. Flow regime comparisons have been made with the Steiner [1], Kattan-Thome-Favrat [2], and Baker [3] flow regime maps.

On Instabilities in Horizontal Two-Phase Flow

1994 ◽  
Vol 59 (12) ◽  
pp. 2595-2603
Author(s):  
Lothar Ebner ◽  
Marie Fialová
Keyword(s):  
Differential Equation ◽  
Flow Regime ◽  
Slug Flow ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Annular Flows ◽  
Flow Regime Maps

Two regions of instabilities in horizontal two-phase flow were detected. The first was found in the transition from slug to annular flow, the second between stratified and slug flow. The existence of oscillations between the slug and annular flows can explain the differences in the limitation of the slug flow in flow regime maps proposed by different authors. Coexistence of these two regimes is similar to bistable behaviour of some differential equation solutions.

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