scholarly journals Effect of Impeller Shape on Solid Particle Suspension

2013 ◽  
Vol 34 (1) ◽  
pp. 139-152 ◽  
Author(s):  
František Rieger ◽  
Tomáš Jirout ◽  
Dorin Ceres ◽  
Pavel Seichter
Keyword(s):  
Power Consumption ◽  
Solid Particle ◽  
Solid Particles ◽  
Impeller Speed ◽  
Particle Suspension ◽  
Particle Sizes ◽  
Wide Range ◽  
Pitched Blade Turbine ◽  
Suspension Measurements

Abstract This paper deals with the effect of impeller shape on off-bottom particle suspension. On the basis of numerous suspension measurements, correlations are proposed for calculating the just-suspended impeller speed for a standard pitched four-blade turbine and three types of hydrofoil impellers produced by TECHMIX for several particle sizes and for a wide range of particle concentrations. The suspension efficiency of the tested impellers is compared with the efficiency of a standard pitched blade turbine on the basis of the power consumption required for off-bottom suspension of solid particles. It is shown that the standard pitched blade turbine needs highest power consumption, i.e. it exhibits less efficiency for particle suspension than hydrofoil impellers produced by TECHMIX.

scholarly journals Computational fluid dynamics simulation of solid-liquid suspension characteristics in a stirred tank with punched circle package impellers

2020 ◽  
Vol 18 (9) ◽  
Author(s):  
Deyin Gu ◽  
Mei Ye ◽  
Zuohua Liu
Keyword(s):  
Fluid Dynamics ◽  
Power Consumption ◽  
Solid Particle ◽  
Particle Diameter ◽  
Solid Particles ◽  
Stirred Tank ◽  
Impeller Speed ◽  
Particle Suspension ◽  
Liquid Suspension ◽  
Solid Liquid

AbstractSolid-liquid suspension characteristics in a stirred tank with four pitched-blade impellers, circle package impellers, and punched circle package impellers were studied via computational fluid dynamics (CFD) simulation. A classical Eulerian-Eulerian approach coupled with the standard k-ε turbulence model was adopted to simulate the solid-liquid two-phase turbulent flow. The effects of impeller speed, power consumption, impeller type, aperture size/ratio, solid particle diameter and liquid viscosity on the solid particle suspension quality were investigated. Results showed that the solid particle suspension quality was improved with an increment in the impeller speed. Punched circle package impeller could reduce the just suspension speed and improve the level of homogeneity for solid-liquid mixing process on the basis of four pitched-blade impeller and circle package impeller. The optimum aperture ratio and aperture diameter were 11.8% and 8 mm, respectively, for solid particles suspension process in this work. Smaller particle diameter led to smaller settling velocity and higher solid particle suspension quality. More viscous liquid was easier for sustaining the solid particles in suspension state. Meanwhile, punched circle package impeller can reduce the power consumption compared with four pitched-blade impeller and circle package impeller at the same impeller speed, and enhance the solid integrated velocity, turbulent kinetic energy, and turbulent kinetic energy dissipation rate of solid-liquid mixing system at the same power consumption.

Modeling evaluation on solid-liquid mixing characteristics in a dislocated guide impeller stirred tank

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Deyin Gu ◽  
Fenghui Zhao ◽  
Xingmin Wang ◽  
Zuohua Liu
Keyword(s):  
Power Consumption ◽  
Solid Particle ◽  
Particle Diameter ◽  
Solid Particles ◽  
Stirred Tank ◽  
Mixing Process ◽  
Solid Holdup ◽  
Aperture Ratio ◽  
Liquid Mixing ◽  
Solid Liquid

Abstract The solid-liquid mixing characteristics in a stirred tank with pitched blade impellers, dislocated impellers, and dislocated guide impellers were investigated through using CFD simulation. The effects of impeller speed, impeller type, aperture ratio, aperture length, solid particle diameter and initial solid holdup on the homogeneity degree in the solid-liquid mixing process were investigated. As expected, the solid particle suspension quality was increased with an increase in impeller speed. The dislocated impeller could reduce the accumulation of solid particles and improve the cloud height compared with pitched blade impeller under the same power consumption. The dislocated guide impeller could enhance the solid particles suspension quality on the basis of dislocated impeller, and the optimum aperture ratio and aperture length of dislocated guide impeller were 12.25% and 7 mm, respectively, in the solid-liquid mixing process. Smaller solid particle diameter and lower initial solid holdup led to higher homogeneity degree of solid-liquid mixing system. The dislocated guide impeller could increase solid particle integrated velocity and enhance turbulent intensity of solid-liquid two-phase compared with pitched blade impeller and dislocated impeller under the same power consumption.

A Combined CFD-Mechanistic Approach for Predicting Solid Particle Erosion in Annular Flow in Pipe Fittings and Elbows

2020 ◽  
Author(s):  
Farzin Darihaki ◽  
Elham Fallah Shojaie ◽  
Jun Zhang ◽  
Siamack A. Shirazi
Keyword(s):  
Multiphase Flow ◽  
Solid Particle ◽  
Annular Flow ◽  
Large Diameter ◽  
Solid Particles ◽  
Wall Material ◽  
Solid Particle Erosion ◽  
Flow Conditions ◽  
Particle Erosion ◽  
Wide Range

Abstract In internal flows, solid particles carried by the fluid could damage pipelines and fittings. Particles that are entrained in the fluid can cross streamlines and transfer a part of their momentum to the internal surface by impacts and cause local wall material degradation. Over the past decades, a wide range of models is introduced to predict particle erosion which includes empirical models, mechanistic models, and CFD which is currently the state-of-art numerical approach to simulate the erosion process. Multiphase flow under annular flow conditions adds to the complexity of the model. Although with the current computational capabilities transient CFD models are effectively applicable, this type of transient multiphase approach is not practical yet for engineering prediction of erosion especially for the large diameter applications with huge computational domains. Therefore, the presented combined approach could be utilized to obtain erosion rates for large diameter cases. Thus, an approach combining CFD and mechanistic multiphase models characterizing annular flow is developed to predict solid particle erosion. Different factors including film thickness in pipes and fittings which are affecting erosion under gas-dominated multiphase flow conditions are investigated. The results from the current approach are compared to experimental data and transient CFD simulations for annular flow in elbows showing a very good agreement with both.

Experimental Characterization of Slug Flow on Solid Particle Transport in a 1 Deg Upward Inclined Pipeline

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Afshin Goharzadeh ◽  
Peter Rodgers ◽  
Liang Wang
Keyword(s):  
Solid Particle ◽  
Solid Particles ◽  
Particle Suspension ◽  
Two Phase ◽  
Horizontal Orientation ◽  
Suspension Layer ◽  
Load Mode ◽  
Gas Liquid Flow ◽  
Liquid Flows ◽  
Pipe Inclination

This paper presents an experimental investigation on the influence of hydraulic and two phase (gas-liquid) flows on sand dune transportation resulting from a stationary flatbed, for horizontal and 1 deg upward pipe inclination. For gas-liquid conveying of solid particles, pipe inclination resulted in considerably different transport phenomena relative to those observed for horizontal orientation. Key distinguishing features such as backward bed movement and enhanced particle suspension were observed and were found to be highly gas-liquid ratio dependent. Using image processing, the solid particle suspension layer was quantified as a function of the gas-liquid flow. The measurements presented provide fundamental insights into the influence of upward pipe inclination on bed-load mode solid transportation in a closed conduit.

Experimental Investigation of Solid Particle Erosion in S-Bend

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Quamrul H. Mazumder ◽  
Kawshik Ahmed ◽  
Siwen Zhao
Keyword(s):  
Experimental Investigation ◽  
Solid Particle ◽  
Solid Particle Erosion ◽  
Surface Erosion ◽  
Particle Sizes ◽  
Air Velocity ◽  
Particle Erosion ◽  
Fluid Handling ◽  
Wide Range ◽  
Cause Of Failure

Solid particle erosion is a micromechanical process that removes material from the surface. Erosion is a leading cause of failure in fluid handling equipment such as pumps and pipes. An investigation was conducted using an S-bend geometry with 12.7 mm inside diameter, r/D ratio of 1.5 with three different air velocities and two different particle sizes. This paper presents the preliminary results of an investigation to determine the location of erosion for a wide range of conditions. The experimental results showed the location of maximum erosion at 29–42 deg from the inlet at 45.72 m/s air velocity with 300 μm particle sizes.

Investigation of Particle Size Effects on Solid Particle Erosion of Elbows in Series for Liquid-Solid Flows

2021 ◽  
Author(s):  
Yeshwanthraj Rajkumar ◽  
Soroor Karimi ◽  
Siamack A. Shirazi
Keyword(s):  
Particle Size ◽  
Solid Particle ◽  
Size Effects ◽  
Oil And Gas ◽  
Solid Particles ◽  
Solid Particle Erosion ◽  
Particle Sizes ◽  
Particle Erosion ◽  
Particle Size Effects ◽  
In Series

Abstract The entrainment of solid particles within the produced fluids can cause solid particle erosion by impacting the piping of production and transportation facilities. Liquid dominated flows are commonly encountered in deep water subsea pipelines while producing oil and gas fluids. It is of great importance to predict the erosion pattern and magnitude for elbows in series in liquid-solid flows as in the oil and gas productions, liquids tends to produce more solid particles compared to gas-solid flows. In the current work, erosion of elbows in series for different particle sizes are investigated by using computational fluid dynamics (CFD) and compare the erosion pattern results with the results of paint removal experiments using a 76.2 mm diameter acrylic elbows, qualitatively. CFD simulations have been performed to study the particle size effects on erosion using Reynolds stress turbulence model (RSM) and Low-Reynolds number K-ε model. Grid refinement studies have been performed and particles are rebounded at the particle radius to accurately examine the effects of particle sizes on solid particle erosion of these elbows. The CFD results shows that significant erosion is observed at the inner wall of the first elbow for larger particles, and the maximum erosion can be seen towards the end of the second elbow for 300 μm particle size.

The Mechanism of Material Removal in the Erosive Cutting of Brittle Materials

1966 ◽  
Vol 88 (4) ◽  
pp. 393-399 ◽  
Author(s):  
G. L. Sheldon ◽  
I. Finnie
Keyword(s):  
Brittle Materials ◽  
Strength Distribution ◽  
Solid Particles ◽  
Particle Sizes ◽  
Normal Impact ◽  
Wide Range ◽  
Flaw Parameter ◽  
Silicon Carbide Particles ◽  
Carbide Particles ◽  
Number Of Particles

An analysis is presented for the erosive cutting of a brittle material by the normal impact of a stream of solid particles. The volume of material removed by a given number of particles is predicted to be: W=krf1(m)Uf2(m) In this expression, k is a quantity involving material constants, r is the average radius, and U the velocity of the impacting particles. The exponents f1(m) and f2(m) are prescribed functions of m, the flaw parameter of the Weibull fracture strength distribution. Tests on a variety of brittle materials, using both angular silicon carbide particles and spherical steel shot, show the predictions of the analysis to be applicable over a wide range of particle sizes and velocities.

Simulation of Impaction Between Liquid Droplet and Solid Particles Based on SPH Method

2014 ◽  
Author(s):  
Shuai Meng ◽  
Qian Wang ◽  
Rui Yang
Keyword(s):  
Surface Tension ◽  
Solid Particle ◽  
Liquid Droplet ◽  
Particle Interaction ◽  
Solid Particles ◽  
Seed Particle ◽  
Liquid Droplets ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Spray Granulation

The phenomenon of impaction between liquid droplets and solid particles is involved in many scientific problems and engineering applications, such as impaction between sprayed droplet and solid particles in limestone injection desulfurization system and the collision between a droplet of the liquid to be granulated and a seed particle in fluidized bed spray granulation process. There are a lot of factors affected this phenomenon: droplet and particle size, momentum of both liquid droplet and solid particles, materials, surface conditions of the solid particles and so on. However the experimental or numerical researches have been done mostly pay attention to Specific application or process, so the impaction phenomenon has not been through studied, for example how different factors affected the impaction process with its effect on different applications. This paper focuses on the basic issue of interaction between droplet and solid particles. Three main factors were considered: ratio of diameter between the droplet and solid particle, relative velocity and the surface tension (including the contact angle between droplet and solid particle). All the study is based on simulation using SPH (smoothed particle hydrodynamics) method, and the surface tension is simulated by particle-particle interaction.

Effects of fines on liquefaction behaviour in well-graded materials

2017 ◽  
Vol 54 (10) ◽  
pp. 1460-1471 ◽  
Author(s):  
Katherine A. Kwa ◽  
David W. Airey
Keyword(s):  
Critical State ◽  
Soil Mechanics ◽  
State Parameter ◽  
Triaxial Tests ◽  
Particle Sizes ◽  
Graded Materials ◽  
Fines Content ◽  
Cyclic Resistance ◽  
Wide Range ◽  
Soil Behaviour

This study uses a critical state soil mechanics perspective to understand the mechanics behind the liquefaction of metallic ores during transport by ship. These metallic ores are transported at relatively low densities and have variable gradings containing a wide range of particle sizes and fines contents. The effect of the fines content on the location of the critical state line (CSL) and the cyclic liquefaction behaviour of well-graded materials was investigated by performing saturated, standard drained and undrained monotonic and compression-only cyclic triaxial tests. Samples were prepared at four different gradings containing particle sizes from 9.5 mm to 2 μm with fines (<75 μm) contents of 18%, 28%, 40%, and 60%. In the e versus log[Formula: see text] plane, where e is void ratio and [Formula: see text] is mean effective stress, the CSLs shifted upwards approximately parallel to one another as the fines content was increased. Transitional soil behaviour was observed in samples containing 28%, 40%, and 60% fines. A sample’s cyclic resistance to liquefaction depended on a combination of its density and state parameter, which were both related to the fines content. Samples with the same densities were more resistant to cyclic failure if they contained higher fines contents. The state parameter provided a useful prediction for general behavioural trends of all fines contents studied.

A Model for the Effect of Velocity on Erosion of N80 Steel Tubing due to the Normal Impingement of Solid Particles

1992 ◽  
Vol 114 (1) ◽  
pp. 54-64 ◽  
Author(s):  
D. P. Chase ◽  
E. F. Rybicki ◽  
J. R. Shadley
Keyword(s):  
Solid Particle ◽  
Computational Study ◽  
Target Material ◽  
Target Surface ◽  
American Petroleum Institute ◽  
Solid Particles ◽  
Unknown Coefficient ◽  
Conservation Of Energy ◽  
Carrier Fluid ◽  
Erosion Behavior

As part of a combined experimental and computational study of erosion for gas and oil production conditions, a semi-empirical model has been developed to predict erosion ratio behaviors of metals due to solid particle impingement. One use of the model will be to reduce the total number of experiments needed to characterize erosion behavior. The model represents material property information associated with both the target material and the impinging particles, as well as impingement speed. Five different models are examined in terms of ability to predict erosion ratio behavior as a function of impingement speed. The model selected is based on a conservation of energy formulation and fracture mechanics considerations to predict the amount of material removed due to solid particle impingement. The resulting equation to predict the erosion ratio for a given particle size contains one unknown coefficient which is determined through comparison with experimental data. Illustrative examples are presented for data for two different sizes of glass bead solid particles in an oil carrier fluid impinging on an API (American Petroleum Institute) N80 grade steel target at an impingement angle 90 deg to the target surface. Using erosion data at one impingement speed to determine the unknown coefficient, the model was used to predict erosion behavior at a range of other speeds. Good agreement between the erosion ratio data and the values predicted by the model were found for two solid particle sizes. Recommendations for expanding the capabilities of the model are pointed out.

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