Expansion Waves in Two-Phase Pipelines

2006 ◽  
Author(s):  
Alessandro Terenzi
Keyword(s):  
Sound Velocity ◽  
Slip Flow ◽  
Expansion Wave ◽  
Two Phase ◽  
Expansion Waves ◽  
Internal Fluid ◽  
Pressurized Pipelines ◽  
The Impact ◽  
Phase Fluid ◽  
Wave Calculation

The analysis of the expansion wave propagation generated by full-bore ruptures of pressurized pipelines containing compressible fluids must be carried out during the assessment of the possible use of crack arrestors. If the internal fluid is two-phase, the sound velocity dependence from the local void fraction and flow regime has to be taken into account, by considering that it may be much lower than for single phase gases, thus promoting crack propagation. In this paper a model for the simulation of an expansion wave in a two-phase fluid pipeline is presented; this model includes several possible descriptions of the thermodynamics and flow regimes, ranging from the simpler homogeneous equilibrium approach to the non-equilibrium slip flow evaluation. The sound velocity trend inside a rarefaction wave can give rise to particular phenomena as curve inversions and jumps. The impact of different formulations on the expansion wave calculation is discussed, giving hints for the design of the pipelines under consideration.

Numerical Simulation Study on the Wave Dissipating Performance of Air Bubbles Breakwater with Double Air Discharged Pipes

2014 ◽  
Vol 501-504 ◽  
pp. 2112-2115
Author(s):  
Cheng Xing Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Numerical Models ◽  
Variable Density ◽  
Air Bubbles ◽  
Two Phase ◽  
Air Bubble ◽  
The Impact ◽  
Phase Fluid

The numerical simulation of air bubbles breakwater was presented in this paper. The two-phase fluid of water and air was assumed as a variable density fluid. The numerical models were developed by FLUENT in order to explore the air amount scale in the system of air bubbles breakwater . The impact of double air discharged pipes on the wave dissipating performance of air bubble breakwater was obtained, which illuminated that under the condition of equal total air amount of Qp, the wave dissipating performance of air bubbles breakwater with double air discharged pipes breakwater may not be improved in comparison with the air bubbles breakwater with single air discharged pipe.

Numerical Simulation Study on the Submerged Pipe Depth of Air Bubbles Breakwater

2013 ◽  
Vol 353-356 ◽  
pp. 2732-2735
Author(s):  
Cheng Xing Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Incident Wave ◽  
Numerical Models ◽  
Variable Density ◽  
Air Bubbles ◽  
Two Phase ◽  
Air Bubble ◽  
The Impact ◽  
Phase Fluid

The numerical simulation of air bubbles breakwater was presented in this paper. The two-phase fluid of water and air was assumed as a variable density fluid. The numerical models were developed by FLUENT in order to explore the air amount scale in the system of air bubbles breakwater . The impact of submerged pipe depth on the wave dissipating performance of air bubble breakwater was obtained, which illuminated that The submerged pipe depth D is deeper, the wave dissipating performance of air bubbles breakwater is better. Furthermore, the effect of air amount and the incident wave periods on the performance of the air bubbles breakwater was analyzed.

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 Three-Dimensional Water-Based Magneto-Hydrodynamic Rotating Nanofluid Flow over a Linear Extending Sheet and Heat Transport Analysis: A Numerical Approach

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5133
Author(s):  
Azad Hussain ◽  
Mubashar Arshad ◽  
Aysha Rehman ◽  
Ali Hassan ◽  
S. K. Elagan ◽  
...  
Keyword(s):  
Differential Equations ◽  
Comparative Study ◽  
Skin Friction ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Transport Analysis ◽  
The Impact ◽  
Phase Fluid

This comparative study inspects the heat transfer characteristics of magnetohydrodynamic (MHD) nanofluid flow. The model employed is a two-phase fluid flow model. Water is utilized as the base fluid, and zinc and titanium oxide (Zn and TiO2) are used as two different types of nanoparticles. The rotation of nanofluid is considered along the z-axis, with velocity ω*. A similarity transformation is used to transform the leading structure of partial differential equations to ordinary differential equations. By using a powerful mathematical BVP-4C technique, numerical results are obtained. This study aims to describe the possessions of different constraints on temperature and velocity for rotating nanofluid with a magnetic effect. The outcomes for the rotating nanofluid flow and heat transference properties for both types of nanoparticles are highlighted with the help of graphs and tables. The impact of physical concentrations such as heat transference rates and coefficients of skin friction are examined. It is noted that rotation increases the heat flux and decreases skin friction. In this comparative study, Zn-water nanofluid was demonstrated to be a worthy heat transporter as compared to TiO2-water nanofluid.

Expansion of a Very Low Quality Two-Phase Fluid Through a Convergent-Divergent Nozzle

1964 ◽  
Vol 86 (2) ◽  
pp. 247-254 ◽  
Author(s):  
E. S. Starkman ◽  
V. E. Schrock ◽  
K. F. Neusen ◽  
D. J. Maneely
Keyword(s):  
Experimental Data ◽  
Slip Flow ◽  
Design Criteria ◽  
Saturated Liquid ◽  
Two Phase ◽  
Flow Rates ◽  
Isentropic Expansion ◽  
Mass Flow Rates ◽  
Laval Nozzles ◽  
Phase Fluid

Flow in de Laval nozzles of high pressure, low-quality steam-water mixtures was investigated to determine the resulting mass flow rates and to acquire design criteria information. Qualities ranged from 0 to 20 percent and pressures up to 1000 psia. Comparisons of the experimental data to three simple models: (a) isentropic expansion; (b) frozen composition; and (c) slip flow, showed satisfactory correspondence at all conditions except for qualities very close to saturated liquid. Observation was made that a condition similar to shock resulted when the nozzles were overexpanded.

Experimental Study of Particle Size, Sound Velocity, and Resonance Phenomena in a Two-Phase Foam Flow

2001 ◽  
Vol 32 (4-6) ◽  
pp. 5
Author(s):  
A. P. Sevast'yanov ◽  
I. V. An ◽  
S. I. Vainshtein ◽  
Yu. A. Sevast'yanov ◽  
A. V. Sidnev ◽  
...  
Keyword(s):  
Experimental Study ◽  
Particle Size ◽  
Sound Velocity ◽  
Two Phase ◽  
Foam Flow ◽  
Resonance Phenomena

Volume preserving immersed boundary methods for two-phase fluid flows

2011 ◽  
Vol 69 (4) ◽  
pp. 842-858 ◽  
Author(s):  
Yibao Li ◽  
Eunok Jung ◽  
Wanho Lee ◽  
Hyun Geun Lee ◽  
Junseok Kim
Keyword(s):  
Fluid Flows ◽  
Immersed Boundary ◽  
Immersed Boundary Methods ◽  
Two Phase ◽  
Boundary Methods ◽  
Phase Fluid ◽  
Volume Preserving

scholarly journals Picking up the hydrothermal whisper at Ischia Island in the Covid-19 lockdown quiet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mariarosaria Falanga ◽  
Paola Cusano ◽  
Enza De Lauro ◽  
Simona Petrosino
Keyword(s):  
Pressure Fluctuations ◽  
Hydrothermal Fluids ◽  
Shallow Aquifer ◽  
Two Phase ◽  
Spectral Content ◽  
Ischia Island ◽  
Continuous Noise ◽  
Organ Pipes ◽  
Source Signals ◽  
Phase Fluid

AbstractIn this paper, we analyse the seismic noise at Ischia Island (Italy) with the objective of detecting the hydrothermal source signals taking advantage of the Covid-19 quiescence due to lockdown (strong reduction of anthropogenic noise). We compare the characteristics of the background noise in pre-, during and post-lockdown in terms of spectral content, energy release (RMS) and statistical moments. The continuous noise is decomposed into two independent signals in the 1−2 Hz and 2−4 Hz frequency bands, becoming sharpened around 1 Hz and 3 Hz respectively in lockdown. We propose a conceptual model according to which a dendritic system of fluid-permeated fractures plays as neighbour closed organ pipes, for which the fundamental mode provides the persistent whisper and the first higher mode is activated in concomitance with energy increases. By assuming reasonable values for the sound speed in low vapor–liquid mass fraction for a two-phase fluid and considering temperatures and pressures of the shallow aquifer fed by sea, meteoric and deep hydrothermal fluids, we estimate pipe lengths in the range 200–300 m. In this scheme, Ischia organ-like system can play both continuous whisper and transients, depending on the energy variations sourced by pressure fluctuations in the hydrothermal fluids.

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