Measurement of Velocities in Two-Phase Flow by Laser Velocimetry: Interaction Between Solid Particles’ Motion and Turbulence

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
N. Sad Chemloul ◽  
O. Benrabah
Keyword(s):  
Slip Velocity ◽  
Continuous Phase ◽  
Solid Particles ◽  
Homogeneous Fluid ◽  
Two Phase ◽  
Laser Anemometry ◽  
Kolmogorov Length Scale ◽  
Liquid Suspension ◽  
Large Particles ◽  
Solid Liquid

In this work, an experimental method based on laser anemometry with Doppller effects is developed. This allows the measurement of velocities and their fluctuations in a flow of solid-liquid suspension in an ascendant vertical pipe. In order to distinguish between the signals coming from the continuous phase, water, and those of the glass bead particles larger than the Kolmogorov length scale, an electronic logic circuit was incorporated in the measuring equipment. This enabled the study of both the slip velocity of the solid-liquid suspension and the influence of the large particles on turbulence. The results show that a fine particle suspension, which represents a tracer, behaves as a homogeneous fluid. For large particles, we confirmed the existence of a slip velocity and the effect of particle size on the turbulence. The use of two distinct measurement volumes produces good results for the direct measurement of the turbulent length scales. The results show that the presence of solid particles modifies the turbulence characteristics.

Solid–liquid two-phase flow and erosion calculation of butterfly valves at small opening based on DEM method

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Benliang Xu ◽  
Zuchao Zhu ◽  
Zhe Lin ◽  
Dongrui Wang
Keyword(s):  
Peer Review ◽  
Two Phase Flow ◽  
Solid Particles ◽  
Phase Flow ◽  
Butterfly Valve ◽  
Two Phase ◽  
Content Type ◽  
Small Opening ◽  
Solid Liquid ◽  
The Impact

Purpose The study aims to decrease the effect of solid particles on a butterfly valve, which will cause seal failure and leakage, providing a reference for anti-wear design. Design/methodology/approach In this paper, computational fluid dynamics discrete element method (CFD-DEM) simulation was conducted to study the solid–liquid two-phase flow characteristics and erosion characteristics of a butterfly valve with a different opening. Findings Abrasion at 10% opening is affected by high-speed jets in upper and lower parts of the pipeline, where the erosion is intense. The impact of the jet on the upper part of 20% opening begins to weaken. With the top backflow vortex disappearing, the effect of lower jet is enhanced. Meanwhile, the bottom backflow vortex phenomenon is obvious, and the abrasion position moves downward. At 30% opening, the velocity is further weakened, and the circulation effect of lower flow channel is more obvious than that of the upper one. Originality/value It is the first time to use DEM to investigate the two-phase flow and erosion characteristics at a small opening of a butterfly valve, considering the effect of inter-particle collision. Therefore, this study carries on the thorough analysis and discussion. At the same opening degree, with increasing of the particle size, the abrasion of valve frontal surface increases when the size is less than 150 µm and decreases when it is greater than 150 µm. For the valve backflow surface, this boundary value becomes 200 µm. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0264/

scholarly journals Scale-Up of Solid-Liquid Mixing Based on Constant Power/Volume and Equal Blend Time Using VisiMix Simulation

2018 ◽  
Vol 187 ◽  
pp. 04002
Author(s):  
Megawati ◽  
Bayu Triwibowo ◽  
Karwono ◽  
Waliyuddin Sammadikun ◽  
Rofiatun Musfiroh
Keyword(s):  
Solid Phase ◽  
Scale Up ◽  
Solid Particles ◽  
Liquid Mixing ◽  
Liquid Suspension ◽  
Two Parameters ◽  
Solid Liquid ◽  
Tank Geometry ◽  
Impeller Geometry

Mixing is one of the important process in many areas of chemical industries, for instance pharmaceutical, drug, ink, paint and other industries. Solid-liquid suspension is produced for 80% of all mixing industries such as leaching process, crystallization process, catalytic reactions, precipitation, coagulation, dissolution and other applications. Two main objectives in solid-liquid mixing namely, avoid settling of solid particles on the tank bottom and ensure the solid particles are uniformly distributed. Many factors that can affect the quality of solid-liquid mixing, they are tank geometry, impeller geometry and speed, baffles, viscosity and density of media. Scale-up of the process is important to conduct before produce it on commercial scale. Two parameters for scale-up solid-liquid mixing are equal blend time and power per volume. Before scaling up the process to industrial scale, an engineer must know the condition of the mixture between both of two. VisiMix can simulating scale-up of solid-liquid mixing in order to know the phenomena inside the tank without conducting a large number of experiments and cheaper. The simulation start from keep the ratio of impeller to tank diameter remains constant, then change the condition operation of mixing. In this paper, power per volume parameter is more recommended as a result of the degree of uniformity of solid phase in liquid.

CFD Simulation of Solid Suspension in a Stirred Reactor Driven by a Dual Punched Rigid-Flexible Impeller

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
Deyin Gu ◽  
Zuohua Liu ◽  
Facheng Qiu ◽  
Jun Li ◽  
Changyuan Tao ◽  
...  
Keyword(s):  
Reference Frames ◽  
Cfd Simulation ◽  
Energy Dissipation Rate ◽  
Solid Particles ◽  
Stirred Tank ◽  
Two Phase ◽  
Stirred Reactor ◽  
Solid Suspension ◽  
Computational Fluid Dynamics Cfd ◽  
Solid Liquid

Abstract Solid suspension characteristics were predicted by computational fluid dynamics (CFD) simulation in a stirred tank driven by a dual rigid-flexible impeller and a dual punched rigid-flexible impeller. An Eulerian-Eulerian approach, standard k-ε turbulence model, and multiple reference frames (MRF) technique were employed to simulate the solid-liquid two-phase flow, turbulent flow, and impeller rotation in the stirred tank, respectively. The CFD results showed that dual punched rigid-flexible impeller could increase the axial velocity and turbulent kinetic energy dissipation rate, and decrease the quantity of sediment solid particles compared with dual rigid-flexible impeller. Less impeller power was consumed by dual punched rigid-flexible impeller compared with dual rigid-flexible impeller at the same impeller speed. It was found that punched rigid-flexible impeller was more efficient in terms of solid suspension quality than dual rigid-flexible impeller at the same Pw. The simulated results for the axial solid concentration were in good agreement with the experimental data.

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.

scholarly journals Liquid/solid flow field in a centrifugal pump with different impeller blade types by PIV

2021 ◽  
pp. 002029402110223
Author(s):  
Baocheng Shi ◽  
Kun Xue ◽  
Jianpeng Pan ◽  
XingKai Zhang ◽  
Ruomeng Ying ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Vector Fields ◽  
Solid Particles ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Impeller Blade ◽  
Rotating Speed ◽  
Pressure Surface ◽  
Solid Liquid

In this study, a non-stirred Particle Image Velocimetry (PIV) testing device is developed to measure the flow field in a solid–liquid two-phase centrifugal pump. The pump casing and impeller are made of an organic glass material. Two types of impellers are designed considering different structure parameters. The performance curves of the pump are obtained for the different impellers at a rotating speed of 900 rpm with particle concentrations of 0%, 3%, 5%, and 10%. The flow fields for water and a solid–liquid two-phase mixture for the two impellers are measured utilizing the PIV system in a centrifugal rotating frame at the designed condition. The distribution of the particles, together with its influence on the performance of the different impellers, is analyzed. From a comparison of the relative velocity vector fields, the following can be concluded. First, the pump with a double arc-shaped profile demonstrated a more uniform and stable flow field distribution and higher performance than that with a single arc profile. Secondly, the solid particles were distributed mainly at the outlet of the impeller and volute wall, whereas the concentration distribution of the larger particles tended to match the pressure surface. This research can provide theoretical guidance for the design and optimization of two-phase flow centrifugal pumps.

scholarly journals Influence of Blade Thickness on Solid–Liquid Two-Phase Flow and Impeller Wear in a Ceramic Centrifugal Slurry Pump

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1259
Author(s):  
Yi Tao ◽  
Yongming Bai ◽  
Yingchun Wu
Keyword(s):  
Solid Particle ◽  
Wear Test ◽  
Suction Side ◽  
Solid Particles ◽  
Phase Flow ◽  
Pressure Side ◽  
Particle Trajectories ◽  
Two Phase ◽  
Blade Thickness ◽  
Solid Liquid

The impeller blades of ceramic slurry pumps are usually very thick for the purpose of prolonging the service life. In this paper, numerical simulations and wear test were conducted to investigate the influence of blade thickness on the solid–liquid two-phase flow and impeller wear in a ceramic centrifugal slurry pump. The wear test was conducted for CFD validation. The numerical results show that the incident angles of solid particles increase with increasing blade thickness, which results in larger wrap angles of the solid particle trajectories. The increasing wrap angles of the solid particle trajectories offset the region that the collisions between the blade pressure side and the solid particles side take place towards the impeller exit and lead to more impacts between the solid particles and the blade suction side. The numerical results are in good accordance with the wear pattern of the tested impellers, which demonstrates that the numerical method adopted in this paper is predictable in the abrasion of the impeller of a ceramic centrifugal slurry pump. The experimental results show that an increase in the blade thickness alleviates the abrasion of the leading edges and the pressure side of the impeller blades; however, it also aggravates the abrasion of the blade suction side and decreases the pump performance.

scholarly journals Numerical Simulation of Fine Particle Solid-Liquid Two-Phase Flow in a Centrifugal Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yanping Wang ◽  
Bozhou Chen ◽  
Ye Zhou ◽  
Jianfeng Ma ◽  
Xinglin Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Internal Pressure ◽  
Centrifugal Pump ◽  
Fine Particle ◽  
Volume Concentration ◽  
Two Phase Flow ◽  
Solid Particles ◽  
Phase Flow ◽  
Two Phase ◽  
Solid Liquid

To study the effect of fine particle size and volume concentration on the performance of solid-liquid two-phase centrifugal pump, the mixture multiphase flow model, RNG k-ε turbulence model, and SIMPLEC algorithm were used to simulate the two-phase flow of the centrifugal pump. The effects of particle size and volume concentration on internal pressure distribution, solid volume distribution, and external characteristics were analyzed. The results show that under the design discharge conditions, with the increase of particle size and volume concentration, the internal pressure of the flow field will decrease, and the volume fraction of solid phase in the impeller passage will also decrease as a whole. The solid particles gradually migrate from the suction surface to the pressure surface, and the particles in the volute channel are mainly concentrated in the flow channel near the outlet side of the volute. With the increase of particle size and volume concentration, the negative pressure value at the inlet of centrifugal pump increases, the total pressure difference at the inlet and outlet decreases, and the head and efficiency decrease accordingly.

scholarly journals Relationship between wear formation and large-particle motion in a pipe bend

2019 ◽  
Vol 6 (1) ◽  
pp. 181254 ◽  
Author(s):  
Yi Li ◽  
Hebing Zhang ◽  
Zhe Lin ◽  
Zhaohui He ◽  
Jialiang Xiang ◽  
...  
Keyword(s):  
Particle Motion ◽  
Mass Concentration ◽  
Granular System ◽  
Wall Region ◽  
Two Phase ◽  
Pipe Bend ◽  
Discrete Element Method Simulation ◽  
Large Particles ◽  
Solid Liquid ◽  
The Impact

Fine and large particles flowing through a bend in a pipe move differently and therefore erode the pipe differently. This paper simulates solid–liquid two-phase flow containing large particles in a bend and analyses the relationship between the wear formation and particle motion. Wear experiments are carried out using 3-mm glass bead particles at a mass concentration of 1–15%. At the same time, the flow field and the motion of the granular system are obtained in computational fluid dynamics–discrete element method simulation. The wear formation mechanism is revealed by comparing experiments with numerical simulations. The wear rate of the wall surface increases with the mass concentration, while the marginal growth rate decreases as the mass concentration increases. As the mass concentration increases to a certain value, the degree of wear reaches a maximum and remains unchanged subsequently because of the formation of a particle barrier along the bend wall. The particles near the wall region will bounce forward because of the periodic disturbance flow around particles. The impact of mass bouncing particles causes the formation of the erosion ripple on the test sheet.

Study on Kinetic Characteristics of Solid-Liquid Two-Phase in Transporting Pipeline of Natural Gas Hydrate

2014 ◽  
Vol 881-883 ◽  
pp. 1814-1818
Author(s):  
Li Yan Shang ◽  
Shan Lin Zhao ◽  
Zhen Pan ◽  
Teng Long Huang
Keyword(s):  
Natural Gas ◽  
Multiphase Flow ◽  
Gas Hydrate ◽  
Volume Concentration ◽  
Kinetic Characteristic ◽  
Concentration Field ◽  
Solid Particles ◽  
Natural Gas Hydrate ◽  
Two Phase ◽  
Solid Liquid

Based on multiphase flow theory and calculation method, the distribution of internal multiphase flow field in the vertical rise pipeline of natural gas hydrate is simulated with FLUENT as a tool and the mixture of natural gas hydrate solid particles and water as a medium. The change rules of velocity field and volume concentration field are described and the effect of solid particles diameter, density and volume concentration of the natural gas hydrate on the pressure loss and resistance loss of pipeline is also analyzed deeply. It provides theoretical basis on transporting of natural gas hydrate solid particles by pipeline. Keywords:natural gas hydrate. pipeline. solid-liquid two-phase flow. kinetic characteristic. numerical simulation.

The Numerical Simulation and Performance Analysis of the Vortex Pump for Solid-Liquid Two Phase Medium

2014 ◽  
Vol 527 ◽  
pp. 88-92
Author(s):  
Peng Yun Song ◽  
Hong Li Wang ◽  
Peng Cheng He
Keyword(s):  
Numerical Simulation ◽  
Volume Fraction ◽  
Internal Flow ◽  
Solid Particles ◽  
Two Phase ◽  
Pump Head ◽  
Phase Medium ◽  
And Performance ◽  
Solid Liquid ◽  
The Impact

The numerical simulation of a 3-D model of the internal flow field for a Vortex slurry pump has been analyzed in this paper. The impact of different solids volume fraction on the distribution of solid particle was analyzed. The expression of the pump head and efficiency was derived by the energy equation. The results show that either on the long blades or on the short blades, the content of the solid particles increases with the increasing of the volume fraction. The results by the expression of the pump head and efficiency are compared with the results of the simulations. The conclusions show that the expression results are similar with the numerical simulation results, and the main factors of affecting the inner and outer characteristics are the solid particles.

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