An investigation of pressure transients in pipelines with two-phase bubbly flow

1989 ◽  
Vol 9 (10) ◽  
pp. 1207-1219 ◽  
Author(s):  
K. C. Ng ◽  
C. Yap
Keyword(s):  
Bubbly Flow ◽  
Two Phase ◽  
Pressure Transients

scholarly journals Investigation of the combined effect of air pockets and air bubbles on fluid transients

2017 ◽  
Vol 20 (2) ◽  
pp. 376-392 ◽  
Author(s):  
Oscar Pozos-Estrada
Keyword(s):  
Bubbly Flow ◽  
Combined Effect ◽  
Hyperbolic Partial Differential Equations ◽  
Experimental Investigations ◽  
Air Bubbles ◽  
Two Phase ◽  
Pressure Transients ◽  
Air Pocket ◽  
Experimental Apparatus ◽  
Air Pockets

Abstract This paper presents numerical and experimental investigations of the combined effect on pressure transients of air pockets and homogenous water–air bubble mixtures. An air pocket can accumulate at a high point of a pipeline along the control section located at the transition between pipes with sub- and supercritical slope, forcing open channel flow conditions underneath the pocket that ends in a hydraulic jump at the downward sloping pipe. The turbulence action at the jump generates small air bubbles that are entrained and transported along the pipe producing a two-component bubbly flow within the continuous liquid phase. A numerical model is developed, combining the explicit–implicit scheme proposed by McGuire and Morris and the method of characteristics for solving the quasi-linear hyperbolic partial differential equations for transient two-phase flow expressed in conservation form. To verify the proposed model, an experimental apparatus made of PVC was used to carry out hydraulic transient experiments. Tests were conducted in a tank–pipe–valve system and a valve with a pneumatic actuator at the downstream end generated transients. Numerical results at the test section pipe compares favorably with experimental data. The results show that pressure transients are significantly reduced with increasing air-pocket volumes and bubbly flow air content.

Effects of water–air mixtures on hydraulic transients

2010 ◽  
Vol 37 (9) ◽  
pp. 1189-1200 ◽  
Author(s):  
Oscar Pozos ◽  
Alejandro Sanchez ◽  
Eduardo A. Rodal ◽  
Yuri V. Fairuzov
Keyword(s):  
Bubbly Flow ◽  
Experimental Investigations ◽  
Hydraulic Transients ◽  
Two Phase ◽  
Pressure Transients ◽  
Air Content ◽  
Air Pocket ◽  
Pressurized Pipelines ◽  
Air Pockets ◽  
The Impact

The purpose of this study is to investigate pressurized pipelines and the potential effects on pressure transients of air entrained at the downstream end of large entrapped air pockets followed by a hydraulic jump in pressurized pipelines. The homogeneous two-phase flow model is used to simulate the transient response of the bubbly mixture after a pump shutdown. The results show that pressure transients are significantly reduced with increasing air-pocket volumes and bubbly flow air content. Experimental investigations were carried out to analyze the impact of different air-pocket volumes located at high points of pressurized pipelines. A case study of an existing pumping system was considered to exemplify the impact of the bubbly flow air content on hydraulic transients.

scholarly journals Shock Phenomena in a One-component Two-phase Bubbly Flow : 1st Report, Experimental Results on Transient Pressure Profiles

1986 ◽  
Vol 29 (258) ◽  
pp. 4235-4240
Author(s):  
Terushige FUJII ◽  
Koji AKAGAWA ◽  
Nobuyuki TAKENAKA ◽  
Sadao TSUBOKURA ◽  
Yoichi HIRAOKA ◽  
...  
Keyword(s):  
Bubbly Flow ◽  
Experimental Results ◽  
Transient Pressure ◽  
Two Phase ◽  
Pressure Profiles

Prediction of Pump Performance Under Air-Water Two-Phase Flow Based on a Bubbly Flow Model

1993 ◽  
Vol 115 (4) ◽  
pp. 781-783 ◽  
Author(s):  
Kiyoshi Minemura ◽  
Tomomi Uchiyama
Keyword(s):  
Two Phase Flow ◽  
Bubbly Flow ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Flow Conditions ◽  
Two Phase ◽  
Performance Change ◽  
Void Fractions ◽  
Two Phases

This paper is concerned with the determination of the performance change in centrifugal pumps operating under two-phase flow conditions using the velocities and void fractions calculated under the assumption of an inviscid bubbly flow with slippage between the two phases. The estimated changes in the theoretical head are confirmed with experiments within the range of bubbly flow regime.

Prediction of pressure surge in a one-component two-phase bubbly flow

1986 ◽  
Vol 95 ◽  
pp. 329-341
Author(s):  
Koji Akagawa ◽  
Terushige Fujii ◽  
Sadao Tsubokura ◽  
Hajime Matsushita ◽  
Yoichi Hiraoka
Keyword(s):  
Bubbly Flow ◽  
Two Phase ◽  
Pressure Surge

Interfacial Structures and Regime Transition in Co-Current Downward Bubbly Flow

2004 ◽  
Vol 126 (4) ◽  
pp. 528-538 ◽  
Author(s):  
S. Kim ◽  
S. S. Paranjape ◽  
M. Ishii ◽  
J. Kelly
Keyword(s):  
Two Phase Flow ◽  
Bubbly Flow ◽  
Superficial Velocity ◽  
Phase Flow ◽  
Two Phase ◽  
Drift Flux Model ◽  
Drift Flux ◽  
Flow Parameters ◽  
Interfacial Structures ◽  
Flux Model

The vertical co-current downward air-water two-phase flow was studied under adiabatic condition in round tube test sections of 25.4-mm and 50.8-mm ID. In flow regime identification, a new approach was employed to minimize the subjective judgment. It was found that the flow regimes in the co-current downward flow strongly depend on the channel size. In addition, various local two-phase flow parameters were acquired by the multi-sensor miniaturized conductivity probe in bubbly flow. Furthermore, the area-averaged data acquired by the impedance void meter were analyzed using the drift flux model. Three different distributions parameters were developed for different ranges of non-dimensional superficial velocity, defined by the ration of total superficial velocity to the drift velocity.

scholarly journals Development of Bubble Size Correlation for Adiabatic Forced Convective Bubbly Flow in Low Pressure Condition Using CFD Code

2020 ◽  
Vol 10 (16) ◽  
pp. 5443
Author(s):  
Jinyeong Bak ◽  
Huiyung Kim ◽  
Jae Jun Jeong ◽  
Dongjin Euh ◽  
Byongjo Yun
Keyword(s):  
Bubble Size ◽  
Bubbly Flow ◽  
Flow Analysis ◽  
Low Pressure ◽  
Good Prediction ◽  
Two Phase ◽  
Local Bubble ◽  
Computational Fluid Dynamics Cfd ◽  
Bubble Number ◽  
Bubble Number Density

In a multidimensional two-phase flow analysis, bubble size significantly affects interfacial transfer terms such as mass, momentum, and energy. With regard to bubbly flow, the application of a simple correlation-type bubble size model presents certain advantages, including short calculation times and ease of usage. In this study, we propose a semi-theoretical correlation developed from a steady state bubble number density transport equation for predicting the distribution of local bubble size using a computational fluid dynamics (CFD) code. The coefficients of the new correlation were determined using the local bubble parameters obtained on the basis of three existing vertical air-water experiments. Finally, these were implemented in commercial CFD code and evaluated against experimental data, which showed that the proposed correlation exhibits good prediction capability for forced convective air-water bubbly flows under low pressure conditions.

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