Numerical Simulation of Acoustic Streaming in Gas-Liquid Two-Phase Flow

2005 ◽  
Author(s):  
Bo Lu ◽  
Arthur E. Ruggles
Keyword(s):  
Numerical Solutions ◽  
Two Phase Flow ◽  
Bubble Radius ◽  
Acoustic Streaming ◽  
Gas Bubbles ◽  
Homogeneous Distribution ◽  
Phase Flow ◽  
Sinusoidal Vibration ◽  
Two Phase ◽  
Left Wall

Acoustic streaming phenomena pertaining to liquid-gas two-phase flow in a one-dimensional rigid duct is investigated numerically. The oscillatory bubbly flow is generated due to the sinusoidal vibration of the vertical left wall of the enclosure. Time-averaged streaming flow patterns exist in the duct as a consequence of interaction between gas bubbles and liquid which are similar to the Rayleigh-type acoustic streaming phenomena extensively investigated in single-phase flow. The liquid is treated as incompressible with a homogeneous distribution of non-condensable gas bubbles. The system is modeled with coupled nonlinear and flux-conservative partial differential equations combined with the Rayleigh-Plesset equation governing the bubble radius. The viscous interaction between bubbles and the surrounding incompressible liquid phase is the main mechanism for attenuation of the wave energy considered in this analysis. The numerical solutions are obtained by a control-volume based finite-volume Lagrangian method.

From disturbance to measurement: Application of Coriolis meter for two-phase flow with gas bubbles

2021 ◽  
Vol 79 ◽  
pp. 101892
Author(s):  
Hao Zhu ◽  
Alfred Rieder ◽  
Wolfgang Drahm ◽  
Yaoying Lin ◽  
Andreas Guettler ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Gas Bubbles ◽  
Phase Flow ◽  
Two Phase

The Effects of Forced Vibration on Two-Phase Flow in a Small Diameter Tube

2003 ◽  
Author(s):  
Akira Kariyasaki ◽  
Akiharu Ousaka ◽  
Tohru Fukano ◽  
Masazumi Kagawa
Keyword(s):  
Pressure Drop ◽  
Forced Vibration ◽  
Two Phase Flow ◽  
Longitudinal Vibration ◽  
Phase Flow ◽  
Lateral Vibration ◽  
Sinusoidal Vibration ◽  
Two Phase ◽  
Specific Flow ◽  
Wide Range

The effects of forced vibrations on the motion of air-water two-phase mixture were studied in 2.4mm I.D. horizontal tube over rather wide range of flow conditions (about 60 flows for lateral vibration, 4 flows and 1 stagnant mixture for longitudinal vibration). 13 different modes of sinusoidal vibration with 1–8mm amplitude and 1–7.7 Hz frequency were exerted on the test tube. Pressure drop, void fraction and flow pattern of the two-phase flow were compared to those of the flow without forced vibration. It was made clear that the lateral vibration exerted on the tube induced a self exciting fluctuation of the pressure drop for a specific flow condition and longitudinal vibration on the tube promoted the bubble coalescence.

Flow Visualization of Unsteady and Transient Phenomena in a Mixed-Flow Multiphase Pump

2016 ◽  
Author(s):  
Alberto Serena ◽  
Lars E. Bakken
Keyword(s):  
Two Phase Flow ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Homogeneous Distribution ◽  
Phase Flow ◽  
Two Phase ◽  
Inlet Flow ◽  
Transient Phenomena ◽  
Multiphase Pump

The flow inside of turbomachines rotating channels, when operating away from the design point, is intrinsically unsteady; two-phase flow and part-load operation further complicate the analysis, introducing additional challenges. Transient phenomena, linked to the typical unsteadiness of multiphase flows (bubble formation, coalescence or breakdown, segregation and gas locking) and to variable inlet flow compositions, as in case of slug flow, require advanced analysis tools which can reveal the local flow mechanisms responsible for performance degradation and instabilities. General trends can be outlined, but the air accumulation zones and two-phase flow patterns are highly dependent on the machine design. The flow regimes vary from a homogeneous distribution of fine bubbles, evenly dispersed and carried away by the main flow, to more complex flow patterns, especially when the phases separate or the bubbles coalesce forming a gas pocket which adheres to a wide portion of the channel wall. Tests are performed on a multiphase pump laboratory, recently installed at the Norwegian University of Science and Technology, which allows a complete optical access to the pump channels and fine adjustments in the inlet configuration and the tip clearance gap; the air can be injected from different locations producing transient regimes too. A high speed camera provides an interesting insight into the transient flow phenomena. This paper focuses on these specific ones: - Irregular backflow and swirl at the inlet section - Gas accumulation zones and contribution of the tip leakage to mixing - Flow pattern shift to phase segregation, as the relative flow is reduced - Origin of pump blockage, when increasing gas contents cannot be carried away by the water phase - Flow and machine parameters response to a variation in the inlet flow Tests are performed at various operating conditions — rotational speed, mixture composition and impeller tip clearance. The study is completed with the time and frequency domain analysis of the pressure pulsations at surging and during specific transient events.

scholarly journals Modeling Two-Phase Flow With Offshore Applications

2005 ◽  
Author(s):  
Rik Wemmenhove ◽  
Erwin Loots ◽  
Roel Luppes ◽  
Arthur E. P. Veldman
Keyword(s):  
Numerical Model ◽  
Gas Phase ◽  
Flow Model ◽  
Two Phase Flow ◽  
Gas Bubbles ◽  
Phase Model ◽  
Green Water ◽  
Phase Flow ◽  
Complex Flow ◽  
Two Phase

With the trend towards offshore LNG production and offloading, sloshing of LNG in partially filled tanks has become an important research subject for the offshore industry. LNG sloshing may induce impact pressures on the containment system and may affect the motions of the LNG carrier. So far, LNG sloshing has been studied mainly using model experiments with an oscillation tank. However, the development of Navier-Stokes solvers with a detailed handling of the free surface allows the numerical simulation of sloshing. It should be investigated, however, how accurate the results of this type of simulations are for this complex flow problem. The paper first presents the details of the numerical model, an improved Volume Of Fluid (iVOF) method. The program has been developed initially to study the sloshing of liquid fuel in satellites. Later, the numerical model has been used for calculations of green water loading and the analysis of anti-roll tanks, including the coupling with ship motions. Recently, the model has been extended to incorporate two-phase flow. This extension improves its ability to simulate the effect of gas bubbles of different sizes. Gas bubbles are present in virtually all relevant offshore situations; not only at LNG sloshing but also during green water events, bow slamming and water entry. In a two-phase flow model, both the liquid and the gas phase can have their own continuity and momentum equations. The handling of the compressibility of the gas phase is a major issue in the design of a two-phase flow model. However, as a first step in the modeling process, the gas phase is considered as incompressible. For a dambreak experiment, results of the one-phase model, the incompressible two-phase model and model experiment results have been compared. It is shown that the physics are more accurately simulated with the incompressible two-phase model. Furthermore, the paper will show results of the incompressible model for LNG sloshing. The physics of LNG sloshing and several other applications can be approached better by taking the compressibility into account. Therefore, as a second step, a compressible model is currently under construction, involving adiabatic compression of the gas phase.

scholarly journals The effect of effective rock viscosity on 2D magmatic porosity waves

2019 ◽  
Author(s):  
Janik Dohmen ◽  
Harro Schmeling ◽  
Jan Philipp Kruse
Keyword(s):  
Bulk Viscosity ◽  
Numerical Solutions ◽  
Two Phase Flow ◽  
Fluid Phase ◽  
Analytic Solutions ◽  
Phase Flow ◽  
Two Phase ◽  
Source Regions ◽  
The Matrix ◽  
Melt Segregation

Abstract. In source regions of magmatic systems the temperature is above solidus and melt ascent is assumed to occur predominantly by two-phase flow which includes a fluid phase (melt) and a porous deformable matrix. Since McKenzie (1984) introduced his equations for two-phase flow, numerous solutions have been studied one of which predicts the emergence of solitary porosity waves. By now most analytical and numerical solutions for these waves used strongly simplified models for the shear- and bulk viscosity of the matrix, significantly overestimating the viscosity or completely neglecting the porosity-dependence of the bulk viscosity. Schmeling et al. (2012) suggested viscosity laws in which the viscosity decreases very rapidly for small melt fractions. They are incorporated into a 2D finite difference mantle convection code with two-phase flow (FDCON) to study the ascent of solitary porosity waves. The models show that, starting with a Gaussian shaped wave, they rapidly evolve into a solitary wave with similar shape and a certain amplitude. Despite the strongly weaker rheologies compared to previous viscosity laws the effect on dispersion curves and wave shape are only moderate as long as the background porosity is fairly small. The models are still in good agreement with semi-analytic solutions which neglect the shear stress term in the melt segregation equation. However, for higher background porosities and wave amplitudes associated with a viscosity decrease of 50% or more, the phase velocity and the width of the waves are significantly decreased. Our models show that melt ascent by solitary waves is still a viable mechanism even for more realistic matrix viscosities.

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