scholarly journals Prospects for the application of radiometric methods in the measurement of two-phase flows

2018 ◽  
Vol 180 ◽  
pp. 01001
Author(s):  
Marcin Zych
Keyword(s):  
Environmental Protection ◽  
Solid Phase ◽  
Life Sciences ◽  
Solid Particles ◽  
Gas Mixture ◽  
Gas Flows ◽  
Mathematical Methods ◽  
Two Phase Flows ◽  
Two Phase ◽  
Phase Mixture

The article constitutes an overview of the application of radiometric methods in the research of two-phase flows: liquid-solid particles and liquid-gas flows. The methods which were used were described on the basis of the experiments which were conducted in the Water Laboratory of the Wrocław University of Environmental and Life Sciences and in the Sedimentological Laboratory of the Faculty of Geology, Geophysics and Environmental Protection, AGH-UST in Kraków. The advanced mathematical methods for the analysis of signals from scintillation probes that were applied enable the acquisition of a number of parameters associated with the flowing two-phase mixture, such as: average velocities of the particular phases, concentration of the solid phase, and void fraction for a liquid-gas mixture. Despite the fact that the application of radioactive sources requires considerable carefulness and a number of state permits, in many cases these sources become useful in the experiments which are presented.

Experimental Characterization of Particle-Laden Air Flow Across Horizontal Pipe Junctions

2018 ◽  
Author(s):  
Tariq S. Khan ◽  
Mohamed Alshehhi ◽  
Xu Rumin ◽  
Saqib Salam
Keyword(s):  
Mass Fraction ◽  
Solid Phase ◽  
Flow Behavior ◽  
Air Flow ◽  
Industrial Applications ◽  
Solid Particles ◽  
Gas Flows ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Particle Sizer

There are several industrial applications in which two phase solid-gas flows are involved. At times, pipe junctions are involved where flow split takes place. Present study consists of experimental investigation of turbulent gas-solid two-phase flow through horizontal pipe junctions. The effects of air flow rate, branch diameter and pipe orientation at junctions are investigated on mass fraction, phase split and solid particles distribution across the junctions. Silica powder, in the monodispersed size of 15 μm was injected into the pipelines by a micro-feeder. The powder was entrained in an air flow which passed horizontally through a long straight channel of circular pipe with T and Y junctions. The main pipe was 51mm in diameter while the inlet superficial velocity of gas was varied from 5 m/s to 13.5m/s. The particles mass concentration was measured by the aerodynamic particle sizer (APS). Experimental results showed that solid phase split followed air flow split while decreasing the inlet air velocity caused major decrease in the mass fraction at junction pipe. The orientation of junction pipe has a significant effect on the flow behavior along the pipe. These results indicate that the behavior of solid particles is a complex phenomenon in pipe flows.

scholarly journals Experimental Analysis of Gas–Liquid–Solid Three-Phase Flows in Horizontal Pipelines

2020 ◽  
Vol 105 (4) ◽  
pp. 1035-1054
Author(s):  
Paolo Sassi ◽  
Youssef Stiriba ◽  
Julia Lobera ◽  
Virginia Palero ◽  
Jordi Pallarès
Keyword(s):  
Flow Visualization ◽  
Flow Regime ◽  
Solid Particles ◽  
High Complexity ◽  
Flow Conditions ◽  
Two Phase Flows ◽  
Two Phase ◽  
Three Phase ◽  
Inner Diameter ◽  
The Individual

AbstractThe dynamics of three-phase flows involves phenomena of high complexity whose characterization is of great interest for different sectors of the worldwide industry. In order to move forward in the fundamental knowledge of the behavior of three-phase flows, new experimental data has been obtained in a facility specially designed for flow visualization and for measuring key parameters. These are (1) the flow regime, (2) the superficial velocities or rates of the individual phases; and (3) the frictional pressure loss. Flow visualization and pressure measurements are performed for two and three-phase flows in horizontal 30 mm inner diameter and 4.5 m long transparent acrylic pipes. A total of 134 flow conditions are analyzed and presented, including plug and slug flows in air–water two-phase flows and air–water-polypropylene (pellets) three-phase flows. For two-phase flows the transition from plug to slug flow agrees with the flow regime maps available in the literature. However, for three phase flows, a progressive displacement towards higher gas superficial velocities is found as the solid concentration is increased. The performance of a modified Lockhart–Martinelli correlation is tested for predicting frictional pressure gradient of three-phase flows with solid particles less dense than the liquid.

Numerical Investigation of Thermofluid Flow Characteristics With Phase Change Against High Heat Flux in Porous Media

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Kazuhisa Yuki ◽  
Jun Abei ◽  
Hidetoshi Hashizume ◽  
Saburo Toda
Keyword(s):  
Heat Flux ◽  
Solid Phase ◽  
Flow Characteristics ◽  
High Heat ◽  
High Heat Flux ◽  
Phase Flow ◽  
Two Phase ◽  
Thermal Nonequilibrium ◽  
Phase Mixture ◽  
Flow Case

This study numerically evaluates thermofluid flow characteristics in porous medium by a newly developed “modified two-phase mixture model” applying Ergun’s law and a two-energy model instead of a one-energy model. In a single-phase flow case, thermal nonequilibrium between a solid phase and a fluid phase is observed in the area where imposed heat conducts from a heating wall and further convective heat transfer is more active. The degree of thermal nonequilibrium has a positive correlation with the increase in flow velocity and heat flux input. In the case of two-phase flow, the thermal nonequilibrium is remarkable in the two-phase region because the solid-phase temperature in this region is far beyond saturation temperature. A difference between these two models is obvious especially in the two-phase flow case, so that the numerical simulation with the modified two-phase mixture model is indispensable under the high heat flux conditions of over 1MW∕m2.

A Test Study of 50% Lightning Impulse Breakdown Voltage on Rod-Plane Gap with Two-Phase Mixture of Gas and Solid Particles

2007 ◽  
Vol 9 (6) ◽  
pp. 695-697 ◽  
Author(s):  
He Zhenghao ◽  
Xu Huaili ◽  
Bai Jing ◽  
Yu Fusheng ◽  
Hu Feng ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Solid Particles ◽  
Two Phase ◽  
Test Study ◽  
Lightning Impulse ◽  
Phase Mixture

Vibration and acoustic signal characteristics of solid particles carried in sand-water two-phase flows

2019 ◽  
Vol 345 ◽  
pp. 159-168 ◽  
Author(s):  
Kai Wang ◽  
Gang Liu ◽  
Yichen Li ◽  
Min Qin ◽  
Jinbang Wang ◽  
...  
Keyword(s):  
Acoustic Signal ◽  
Solid Particles ◽  
Two Phase Flows ◽  
Two Phase ◽  
Signal Characteristics

Three-Dimensional Numerical Simulation of Convective Melting of Solid Particles in a Fluid

1999 ◽  
Author(s):  
Y. L. Hao ◽  
Y.-X. Tao
Keyword(s):  
Volume Fraction ◽  
Solid Phase ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Phase Changes ◽  
Solid Particles ◽  
Preliminary Calculation ◽  
Two Phase ◽  
Closed Set ◽  
Gravity Effects

Abstract A physical model of two-phase flow and heat-mass transfer with the phase changes based on the theory of interacting continua is proposed. All terms in the conservation equations are analyzed and the constitutive equations are presented. A closed set of governing equations describing the convective melting of solid particles in a fluid is obtained. The numerical method is developed for the solution of velocity, temperature, and volume fraction of solid phase for the three-dimensional melting in a rectangular cross-section channel. Preliminary calculation, including gravity effects, shows that the result is reasonable. This study provides a basis for the theoretical and experimental investigation of convective melting of solid particles in a fluid.

Method of computing hydraulic gradient for the case of a two-phase mixture flowing in sloping pipes

2019 ◽  
Author(s):  
A.S. Kondratiev ◽  
T.L. Nha
Keyword(s):  
Solid Phase ◽  
Slope Angle ◽  
Axisymmetric Flow ◽  
Volume Ratio ◽  
Hydraulic Gradient ◽  
Transitional Region ◽  
Phase Volume ◽  
Two Phase ◽  
Phase Volume Ratio ◽  
Phase Mixture

The paper investigates two-phase mixture flows in sloping pipes employing two computational methods in the transitional region of pipe slope angle. We used methods of computing two-mixture flows in horizontal and vertical pipes as the basis for our equations. When flowing downwards through a sloping pipe, the solid phase volume ratio distribution changes most significantly: an axisymmetric flow through a vertical pipe transforms into a flow featuring a markedly non-uniform distribution of the solid phase along the vertical plane in the sloping pipe. When flowing upwards, the solid phase volume ratio profile is inversely transformed. Comparison of the experimental and computational data showed that the datasets are in a sufficiently good agreement. The computational method developed is semi-empirical and may be recommended for calculating hydraulic gradient in sloping pipes.

scholarly journals Effect of a Symmetric Contraction on the Concentration Profiles of a Particle-Laden Slurry

2011 ◽  
Author(s):  
A. Deshpande ◽  
K. Ramisetty ◽  
F. W. Chambers ◽  
M. E. McNally ◽  
R. M. Hoffman
Keyword(s):  
Single Phase ◽  
Solid Phase ◽  
Fluid Dynamic ◽  
Density Ratio ◽  
Primary Phase ◽  
Solid Particles ◽  
Concentration Profiles ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Slurry Concentration

In-line measurements and sample stream withdrawals for on-line and/or at-line measurements of slurries flowing in horizontal pipes can be complicated by nonuniform slurry profiles. More uniform profiles would improve measurements. Area contractions are a common means used to produce more uniform velocity fields for single phase flows. For example, contractions are used to condition the flow entering wind tunnel test sections and make velocity profiles more uniform at venturi throats. It was desired to determine whether area contractions could be used to make slurry concentration profiles more uniform in horizontal pipe flows. An ASME flow nozzle with a contraction diameter ratio of 0.5 was chosen as a well defined geometry to consider in a Computational Fluid Dynamic (CFD) study of the effects of a contraction on slurry concentration profiles. The pipe was 2.8 m long with a 50.8 mm diameter. The entrance of the contraction was placed at 35 pipe diameters from the inlet in fully developed flow. A length of 20 diameters followed the contraction. The slurry had a xylene liquid phase and an ADP solid phase with a density ratio of 1.7. The simulations were performed at primary phase velocities of 2 m/s and 4 m/s, corresponding to Reynolds numbers of 1.4E05 and 2.8E05. Spherical particle diameters of 38, 75, and 150 μm were used at concentrations of 0.05, 0.2, and 0.3. ANSYS FLUENT 12 software was used with the standard k-ε turbulence model and standard wall function. The mixture multi-phase model was used for the two-phase flow. An unstructured tetrahedral meshing scheme was used with 1.4 million elements. The grid was adjusted until the condition 30 < y+ <60 for the mesh point nearest the wall was satisfied. A grid refinement study was performed to insure grid independence. The computational scheme first was validated by comparing pipe flow velocity and concentration profiles to results in the literature. The computations performed with the contraction showed that in all cases the concentration profiles of the solid particles displayed greater uniformity than the profiles in the pipe upstream of the contraction. The effect of the contraction was more pronounced for the larger particles. As in the case of single phase flows, the contraction caused the axial turbulence intensity to decrease. The greater uniformity of the concentration profiles at the exit plane of the nozzle, suggest that the contraction can provide better conditions for performing measurements of a particle-laden slurry.

Turbulent Solid-Liquid Two-Phase Flow Simulation With Turbulence Intensity and Time Scale Model

2009 ◽  
Author(s):  
Z. Mansoori ◽  
M. Saffar-Avval ◽  
B. Nojabaii ◽  
F. Behzad ◽  
G. Ahmadi
Keyword(s):  
Time Scale ◽  
Model Comparison ◽  
Two Phase Flow ◽  
Solid Phase ◽  
Solid Particles ◽  
Scale Model ◽  
Particle Collision ◽  
Phase Flow ◽  
Two Phase ◽  
Solid Liquid

Two-dimensional simulation of turbulent solid-liquid flow is carried out. The modeling is established for a two-phase flow of solid particles in a vertical pipe water flow. Governing equations of flow and turbulence field are solved in an Eulerian-Lagrangian approach by the use of k-τ (turbulence time scale) model and trajectories of the particles are obtained using the Lagrangian method with a deterministic inter-particle collision model. Comparison between the results of the model for mean and r.m.s velocities of the liquid and solid phase with the experimental results shows a good agreement. The effect of variation of particle density and concentration are studied.

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