Cyclic Flow Experiments of a Fine Particle Separation Hydrocyclone

2007 ◽  
Author(s):  
Lixin Zhao ◽  
Minghu Jiang
Keyword(s):  
Flow Condition ◽  
Fine Particle ◽  
Fine Particles ◽  
Separation Efficiency ◽  
Amplitude Ratio ◽  
Particle Separation ◽  
Separation Performance ◽  
Period Ratio ◽  
Cyclic Flow ◽  
Signal Type

Basic separating principle of hydrocyclones and the cyclic experimental research facilities are introduced. The difficulty of separating fine particle is described. Based on a solid-liquid hydrocyclone used for separating fine particles, effect of cyclic flow condition on hydrocyclone’s performance is studied. Effects of cyclic period ratio, cyclic flowrate amplitude ratio, Reynolds number, gas liquid ratio, and the cyclical signal type on the hydrocyclone’s fine particle separation performance, especially on relative overflow purifying rate were studied in detail. The results show that the separation efficiency of the hydrocyclone operated under cyclic flow condition can be higher than that in steady condition, when the cyclic period ratio is about 0.68 and the cyclic flowrate amplitude ratio is about 2%. Rectangular wave seems to be the best cyclic signal for enhancing the hydrocyclone’s separation efficiency. The cyclical change of flowrate leads to the increasing of hydrocyclone’s energy consumption to some extent, while the increasing amount is very less, which is no more than 3% in general.

Study of the Particle Separation Performance of a Dust-settling Hopper

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Bofu Wu ◽  
Jinlai Men ◽  
Jie Chen
Keyword(s):  
Fluid Dynamics ◽  
Particle Concentration ◽  
Separation Efficiency ◽  
Simulation Analysis ◽  
Numerical Study ◽  
Particle Separation ◽  
Separation Performance ◽  
Particle Removal ◽  
Airflow Velocity ◽  
Calculation Results

This paper presents a numerical study to predict the particle separation performance of a dust-settling hopper using computational fluid dynamics. The Euler-Lagrange approach was employed to analyze the particle separation efficiency and the outflow particle concentration of the dust-settling hopper under different inlet airflow velocities. The calculation results obtained reveal that the overall particle separation efficiency and the outflow particle concentration decrease with the increase of the inlet airflow velocity, and the particle grade efficiency increases with particle size. Since there is a paradox between the particle separation performance and the particle removal performance for a street vacuum sweeper, it is necessary to counter-balance the effects of the inlet airflow velocity on them. According to the simulation analysis, an appropriate inlet airflow velocity is provided for the design of the dust-settling hopper.

scholarly journals An Experimental Study on Performance and Structural Improvements of a Novel Elutriator

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 478
Author(s):  
Jipeng Dong ◽  
Pan Zhang ◽  
Weiwen Wang ◽  
Jianlong Li ◽  
Guanghui Chen
Keyword(s):  
Gas Flow ◽  
Fine Particles ◽  
Separation Efficiency ◽  
Particle Dispersion ◽  
Operating Conditions ◽  
Separation Performance ◽  
Fine Dust ◽  
Fire Hazards ◽  
Feeding Speed ◽  
Air Speed

During the transportation and packaging of low density polyethylene (LDPE) granular materials, fine dusts such as floccules, powder and fiber will be produced, which pollute the environment, affect product quality and generate fire hazards. In this work, the separation performance of fine dust and optimal operating conditions of an improved elutriator were investigated experimentally. Experiments were carried out to investigate the effects of air speed, feeding speed, and grid layout on the removal efficiency of fine particles. Experimental data showed that the separation efficiency of the novel elutriator ranged from 96% to 98.50%, which was more stable and an average of 51.44% higher than that of the original elutriator. By setting internals and improving the structure, the gas flow field in the equipment was regulated, the particle dispersion was intensified, and the static electricity was eliminated, which significantly improved the separation efficiency of fine dust.

Study of the Transitional Flow and Particle Separation With a Fishhook Effect in a Mini-Hydrocyclone

2012 ◽  
Author(s):  
Guofeng Zhu ◽  
Jong-Leng Liow ◽  
Andrew Neely
Keyword(s):  
Fine Particles ◽  
Separation Efficiency ◽  
Numerical Study ◽  
Particle Interaction ◽  
Particle Separation ◽  
Transitional Flow ◽  
Lagrangian Model ◽  
Correction Coefficient ◽  
Inlet Velocity ◽  
Les Model

The mini-hydrocyclone is being proposed as a micro-separator in complex micro-devices for in-line fine particle separation as it has a concise geometry and no moving parts,. In this work, we present a numerical study combined by experiments on a 5 mm minihydrocyclone to investigate the transitional flow and particle separation with the presence of a fishhook effect. The results showed that the simulation from the LES model gave good agreement with that from DNS at an inlet velocity of 0.4 m/s. The LES model was then used to study the higher inlet velocity cases of 1.0 and 1.8 m/s. The particle separation was predicted by a Lagrangian model with an added user defined function (UDF) in the Fluent code to account for the particle interaction. The modeling results for the three inlet velocities studied showed that small particle Reynolds number, ReP, resulted in a poorly developed wake behind the large particles, which did not entrain fine particles leading to a barely noticeable fishhook effect for the 0.4 m/s inlet velocity. In contrast, a large ReP gives rise to larger wakes, which are capable of entraining fine particles more efficiently causing the pronounced fishhook effect at higher inlet velocities. The results show the particle separation with the fishhook effect could be modeled based on the particle entrainment model, whereas the accurate simulation of the fishhook effect in future should include a correction coefficient that varies with Rep to improve the separation efficiency predictions.

scholarly journals Effect of Overflow Pipe on the Internal Flow Fields and Separation Performance of W-Shaped Hydrocyclones

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 329
Author(s):  
Lanyue Jiang ◽  
Peikun Liu ◽  
Xinghua Yang ◽  
Yuekan Zhang ◽  
Xiaoyu Li ◽  
...  
Keyword(s):  
Axial Velocity ◽  
Fine Particle ◽  
Fine Particles ◽  
Tangential Velocity ◽  
Internal Flow ◽  
Pipe Diameter ◽  
Separation Performance ◽  
Particle Content ◽  
Air Core ◽  
Overflow Pipe

The entrainment of fine particles in underflow of a grinding-classification hydrocyclone can cause ore overgrinding, which will lead to reductions in both metal recovery and ball mill throughput. To address this problem, this paper proposed a W-shaped hydrocyclone that can effectively reduce underflow fine particle entrainment. Experimental tests and numerical simulations were employed to deeply investigate overflow pipe diameter influence on the separation performance and internal flow field of W-shaped hydrocyclones. The effects of overflow pipe diameter on air core shape, velocity field, pressure field, and separation performance were studied. The results revealed that as the diameter of the overflow pipe increased, air core gradually stabilized, and air core diameter gradually increased. The diameter of stabilized air core was approximately 45% to 55% of overflow pipe diameter. As overflow pipe diameter increased, hydrocyclone pressure drop decreased, energy consumption was reduced, the tangential velocity decreased, outer vortex axial velocity did not change significantly, and inner vortex axial velocity gradually increased. At the same time, zero-velocity points gradually moved outward, and the inner vortex region expanded. By the increase of overflow pipe diameter, both the underflow yield and split ratio gradually decreased, the coarse particle content in the overflow product increased, and the fine particle content in the underflow product gradually decreased.

scholarly journals Prediction of Particle-Collection Efficiency for Vacuum-Blowing Cleaning System Based on Operational Conditions

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 809 ◽  
Author(s):  
Yuan Xi ◽  
Yan Dai ◽  
Xi–long Zhang ◽  
Xing Zhang
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Separation Efficiency ◽  
Collection Efficiency ◽  
Particle Separation ◽  
Separation Performance ◽  
Dust Collection ◽  
Operational Conditions ◽  
Dust Collection Efficiency ◽  
Traveling Speed

The dust-collection system, as the core of a sweeper vehicle, directly inhales dust particles on the pavement. The influence of variable operational conditions on particle-separation performance was investigated using computational fluid dynamics (CFD) Euler–Lagrange multiphase model. The particle-separation performance efficiency and retention time were used to evaluate the dust-collection efficiency. The uniform design (UD) and multiple regression analysis (MRA) methods were employed to predict and optimize the effects of reverse-blowing flow rate, pressure drop, and traveling speed on separation efficiency. The results indicated that the dust-collection performance initially increased and then decreased with increasing reverse-blowing flow rate. As the pressure drop increased, there was an increase in total dust-collection efficiency. However, the efficiency decreased with increasing traveling speed. The regression model showed that the proposed approach was able to predict the particle collection efficiency accurately. In addition, the optimum operational conditions were obtained, namely a reverse-blowing flow rate of 2100 m3/h, a traveling speed of 5 km/h, and a pressure drop of 2400 Pa. The maximum particle-separation efficiency was 99.10%, which showed good agreement with the experimental results.

scholarly journals High Concentration Fine Particle Separation Performance in Hydrocyclones

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 307
Author(s):  
Yuekan Zhang ◽  
Meng Yang ◽  
Lanyue Jiang ◽  
Hui Wang ◽  
Jinguang Xu ◽  
...  
Keyword(s):  
Particle Size ◽  
Fine Particle ◽  
Fine Particles ◽  
Volume Fraction ◽  
Separation Performance ◽  
Centrifugal Separation ◽  
Discrete Phase Model ◽  
High Concentration ◽  
Ansys Fluent ◽  
Discrete Phase

The vast majority of current research on hydrocyclone field centrifugal separation focuses on low concentration fluids having volume fraction less than 3%. For high-concentration fluids having volume fractions greater than 10%, which are often encountered in engineering, the law governing particle motion and the classification mechanism are still unclear. In order to gain insights into the interaction between fine particles in the high concentration hydrocyclone field and to improve the hydrocyclone separation performance of these particles, a Dense Discrete Phase Model (DDPM) of the Euler-Eulerian method under the Ansys Fluent 14.5 software was employed. Numerical simulations were carried out to study the characteristics of the hydrocyclone field of dense particles and the influence of parameters, such as the diameter of the overflow outlet, diameter of the underflow outlet, and material concentration, on separation performance. The trajectories and separation efficiencies of two kinds of fine particles with different densities and six different particle sizes at high concentration were obtained. The results show that for the hydrocyclone classification of high-concentration fine particles, particles with large density and small particle size are more likely to enter the internal cyclone and discharge from the overflow. Particles with small density and large particle size are more likely to enter the external cyclone and discharge from the underflow. The research results of this topic could provide a feasible reference and theoretical basis for the centrifugal separation of high-concentration fine particle fluid.

scholarly journals Design of Cyclone Separator Critical Diameter Model Based on Machine Learning and CFD

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1521
Author(s):  
Donggeun Park ◽  
Jeung Sang Go
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Network Model ◽  
Separation Efficiency ◽  
Critical Diameter ◽  
Particle Separation ◽  
Separation Performance ◽  
Cyclone Separator ◽  
Model Based ◽  
Design Variables

In this paper, the characteristics of the cyclone separator was analyzed from the Lagrangian perspective for designing the important dependent variables. The neural network network model was developed for predicting the separation performance parameter. Further, the predictive performances were compared between the traditional surrogate model and the developed neural network model. In order to design the important parameters of the cyclone separator based on the particle separation theory, the force acting until the particles are separated was calculated using the Lagrangian-based computational fluid dynamics (CFD) methodology. As a result, it was proved that the centrifugal force and drag acting on the critical diameter having a separation efficiency of 50% were similar, and the particle separation phenomenon in the cyclone occurred from the critical diameter, and it was set as an important dependent variable. For developing a critical diameter prediction model based on machine learning and multiple regression methods, unsteady-Reynolds averaged Navier-Stokes analyzes according to shape dimensions were performed. The input design variables for predicting the critical diameter were selected as four geometry parameters that affect the turbulent flow inside the cyclone. As a result of comparing the model prediction performances, the machine learning (ML) model, which takes into account the critical diameter and the nonlinear relationship of cyclone design variables, showed a 32.5% improvement in R-square compared to multi linear regression (MLR). The proposed techniques have proven to be fast and practical tools for cyclone design.

scholarly journals The Effect of Inlet Velocity on the Separation Performance of a Two-Stage Hydrocyclone

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 209 ◽  
Author(s):  
Lanyue Jiang ◽  
Peikun Liu ◽  
Yuekan Zhang ◽  
Xinghua Yang ◽  
Hui Wang
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Fine Particle ◽  
Fine Particles ◽  
Coarse Particle ◽  
Separation Performance ◽  
Two Stage ◽  
Inlet Velocity ◽  
Second Stage ◽  
Median Particle

The “entrainment of coarse particles in overflow” and the “entrainment of fine particlesin underflow” are two inevitable phenomena in the hydrocyclone separation process, which canresult in a wide product size distribution that does not meet the requirement of a preciseclassification. Hence, this study proposed a two-stage (TS) hydrocyclone, and the effects of the inletvelocity on the TS hydrocyclone were investigated using computational fluid dynamics (CFD).More specifically, the influences of the first-stage inlet velocity on the second-stage swirling flowfield and the separation performance were studied. In addition, the particle size distribution of theproduct was analyzed. It was found that the first-stage overflow contained few coarse particlesabove 40 μm and that the second-stage underflow contained few fine particles. The second-stageunderflow was free of particles smaller than 10 μm and almost free of particles smaller than 20 μm.The underflow product contained few fine particles. Moreover, the median particle size of thesecond-stage overflow product was similar to that of the feed. Inspired by this observation, wepropose to recycle the second-stage overflow to the feed for re-classification and to use only thefirst-stage overflow and the second-stage underflow as products. In this way, fine particle productsfree of coarse particle entrainment, and coarse particle products free of fine particle entrainmentcan be obtained, achieving the goal of precise classification.

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