The effects of the lower outlet on the flow field of small gas–liquid cylindrical cyclone

2018 ◽  
Vol 233 (4) ◽  
pp. 1262-1270 ◽  
Author(s):  
Weibing Zhu ◽  
Liang Hu ◽  
Xiaobin Zhang
Keyword(s):  
Flow Field ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Energy Losses ◽  
Mean Square ◽  
Root Mean Square Velocity ◽  
Cylindrical Cyclone ◽  
Backflow Zone

In this study, the effects of the lower outlet on the flow field of small gas–liquid cylindrical cyclones are investigated using Reynold stress turbulence model. Under the same operating conditions, four configurations with different outlet styles and angles are established. The time-averaged tangential velocity, axial velocity, and root mean square velocity are compared, respectively. It is shown that many local secondary flow patterns are present in small gas–liquid cylindrical cyclones, and those flow patterns may cause serious energy losses. The lower outlet mainly influences the gas–liquid cylindrical cyclones flow field in the central region. The small gas–liquid cylindrical cyclones with single rectangular outlet provides a steady flow field and a large backflow zone, which are helpful in improving the separation efficiency. According to the simulations, a single rectangular lower outlet is the optimal one for small gas–liquid cylindrical cyclones.

Numerical Simulation of Double Inlet Cylinder Cyclone Using CFD

2013 ◽  
Vol 275-277 ◽  
pp. 558-561
Author(s):  
Xiao Ming Yuan ◽  
Hui Jun Zhao ◽  
Jing Yi Qu
Keyword(s):  
Flow Field ◽  
Volume Fraction ◽  
Separation Efficiency ◽  
Separation Performance ◽  
Two Phase ◽  
Phase Volume Fraction ◽  
Fluid Field ◽  
Cylindrical Cyclone ◽  
Discrete Phase ◽  
New Type

Designed a new type of double inlet cylindrical cyclone. For search the separation performance in a cylindrical cyclone. By use of CFD，applied the RSM turbulence model and Euler two-phase flow method and ASM which to simulate separation process and flow field within a double inlet cylindrical cyclone. Then compared with the single inlet cyclone，obtained velocity distribution. Analyzed the differences of discrete phase volume fraction between different viscosity. The results show that the new-style cyclone caught more stable fluid field and higher separation efficiency. And when the viscosity is about 0.75 kg/m•s， the separation efficiency and stability of the oil core is higher. Preliminary flow field law is shown up.

Flow Field Structures of the Impeller Backside Cavity and Its Influences on the Centrifugal Compressor

2009 ◽  
Author(s):  
Zhigang Sun ◽  
Chunqing Tan ◽  
Dongyang Zhang
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Leakage Flow ◽  
Coupled Flow ◽  
Axial Thrust ◽  
Aerodynamic Performances ◽  
Shaft Power

The impeller backside cavity is one of the unique features of the centrifugal compressors, it can affect the aerodynamic performances of a centrifugal compressor in many ways. This paper presents the researches on the coupled flow fields between a centrifugal compressor main flow passage and its impeller backside cavity. The flow field structures and features of the impeller backside cavity are presented for different leakage flow patterns, and its influences on the flow field details, axial thrust, shaft power, pressure ratio and efficiency of the centrifugal compressor have been studied. Some general conclusions are drawn for different centrifugal compressor operating conditions and impeller backside cavity leakage flow patterns.

scholarly journals A New Rotor-Type Dynamic Classifier: Structural Optimization and Industrial Applications

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1033
Author(s):  
Fangchao Jia ◽  
Xinliang Mou ◽  
Ying Fang ◽  
Chuanwen Chen
Keyword(s):  
Flow Field ◽  
Radial Velocity ◽  
Tangential Velocity ◽  
Operating Conditions ◽  
Bottom Surface ◽  
Cone Type ◽  
Surface Diameter ◽  
Rotor Cage ◽  
Rotor Type ◽  
Classification Efficiency

Due to the inadequate pre-dispersion and high dust concentration in the grading zone of the turbo air classifier, a new rotor-type dynamic classifier with air and material entering from the bottom was designed. The effect of the rotor cage structure and diversion cone size on the flow field and classification performance of the laboratory-scale classifier was comparatively analyzed by numerical simulation using ANSYS-Fluent. The grinding process performance with an industrial classifier was also tested on-site. The results revealed that an inverted cone-type rotor cage is more suitable for the under-feed classifier. When the rotor cage’s top-surface diameter to bottom-surface diameter ratio was too large or too small, the radial velocity and tangential velocity at the outer surface of the rotor cage greatly fluctuated. Furthermore, the diameter of the diversion cone also affected the axial velocity and radial velocity of the flow field. Models T-C(1-0.8) and T-D(1-0.7) were determined as the best rotor cage structures. Under stable operating conditions, the classification efficiency of the industrial classifier was 87% and the sharpness of separation was 0.58, which meet the industrial requirements for classification efficiency and energy consumption. This present study provides theoretical guidance and engineering application value for air classifiers.

CFD Simulation of Liquid-Liquid Hydrocyclone: Oil/Water Application

2009 ◽  
Author(s):  
Nabil Kharoua ◽  
Lyes Khezzar ◽  
Zoubir Nemouchi
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Turbulence Models ◽  
Reynolds Stresses ◽  
Water Separation ◽  
Field Behavior ◽  
Radial Profiles ◽  
Oil Water

In the present work, the oil-water separation occurring inside a de-oiling hydrocyclone is investigated numerically using the RSM [1] and the RNG k-ε [2] turbulence models combined with the multiphase mixture model of Manninen et al. [3] implemented in the commercial code FLUENT. Interesting results are obtained concerning the effects of the inlet oil concentration, the oil droplet size, and the flow rate on the separation efficiency. The results are in agreement with the experimental measurements of Colman et al., [4]. The separation efficiency is known to be unaffected for a large range of inlet oil concentrations (Colman et al. [4], Gomez et al. [5]) and this is confirmed in the present study. In addition to the overall performance parameters, remarkable results describing the flow field behavior are obtained. The radial profiles of the axial and tangential velocity components are discussed. The flow reversal on the axis and the swirling behavior are shown. Results concerning the pressure drops, the friction coefficient and the turbulent Reynolds stresses are also presented. Since detailed results on the flow field for de-oiling hydrocyclones are scarce, the present study might be useful for future studies aiming to improve liquid-liquid separation efficiency depending strongly on the inside flow field behavior.

Numerical Simulation of Flow Field and Separation Efficiency of Inclined Cut-In Double-Inlet Cyclone

2012 ◽  
Vol 184-185 ◽  
pp. 341-347
Author(s):  
Cai Jin Wu ◽  
Zheng Fei Ma ◽  
Yong Yang
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Flow Field ◽  
Axial Velocity ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Three Dimension ◽  
Inclined Angle

The three-dimension flow field and the separation efficiency of the inclined cut-in double-inlet cyclone were simulated numerically with Reynolds Stress Model (RSM). Numerical results show that the flow field nonsymmetry is improved in the inclined cut-in double-inlet cyclone and the swirl in the flow field was decreased greatly compared to that in the single-inlet cyclone. With the increase of inclined angle, both the tangential velocity and the axial velocity first increase and then decrease, reaching a peak at inclined 12 ° angle and at inclined 10 ° angle, respectively. The pressure drop in the inclined cut-in double-inlet cyclone increases first and then decreases with the increase of inclined angle, reaching a maximum far lower than that in the single-inlet cyclone, while the change of the radial velocity is not obvious. The separation efficiency of the inclined cut-in double-inlet cyclone could be effectively improved and the optimum inclined angle is 10 °.

Experimental Investigation of EHD Flow Regimes Map in an Electrostatic Air-Oil Droplets Separator

2011 ◽  
Author(s):  
Xiangling Kong ◽  
Mohamed Alshehhi ◽  
Afshin Goharzadeh
Keyword(s):  
Flow Field ◽  
Applied Voltage ◽  
Electrostatic Precipitator ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Solid Particles ◽  
Inertial Forces ◽  
Gas Velocity ◽  
Oil Droplets ◽  
Wide Range

The applications of ESPs in liquid droplets separation have not been implemented thoroughly as in dust separation. In this paper, flow visualization measurements of the electrohydrodynamic (EHD) flow field in a narrow wire-plate electrostatic precipitator (ESP) were conducted when the primary gas flow was seeded with oil droplets with average diameter of 2μm. The EHD flow field was visualized under wide range of operating conditions by a high speed camera. The tested gas velocities were from 0 to 0.5m/s, and a positive DC voltage varying from 0 to 16kV was applied to the ESP. Experimental results clearly confirmed formation of the secondary flow and the EHD flow patterns changed significantly during corona discharge, depending on the gas velocity and applied voltage. Six typical EHD flow patterns were summarized based on the visualization and an EHD flow regime map was plotted against Reynolds number (Re) and electrohydrodynamic number (Ehd), which represents the relationship between inertial forces and electrical forces. The EHD flow structures were pronounced for high applied voltage (high Ehd) and low gas velocity (low Re) and the primary flow acted to suppress the formation of EHD flow. The EHD flow patterns obtained with oil droplets showed different characteristics, compared to EHD flow with solid particles from previous studies, when both electrics and inertial forces are weak. The high adhesive forces of oil droplets might be the main cause of these differences.

scholarly journals A Downhole Hydrocyclone for the Recovery of Natural Gas Hydrates and Desanding: The CFD Simulation of the Flow Field and Separation Performance

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3257
Author(s):  
Shunzuo Qiu ◽  
Guorong Wang ◽  
Leizhen Wang ◽  
Xing Fang
Keyword(s):  
Flow Field ◽  
Removal Efficiency ◽  
Separation Efficiency ◽  
Solid Phase ◽  
Short Circuit ◽  
Tangential Velocity ◽  
Separation Performance ◽  
Volume Distribution ◽  
Recovery Efficiency ◽  
And Performance

The application of a hydrocyclone to recycle NGH and desand during NGH exploitation is a novel idea. The flow field and performance of this hydrocyclone is in the frontier of the research in this field and is unclear so far. This research aimed to reveal the flow field characteristics and performance of NGH downhole hydrocyclones. In this paper, flow field, solid phase particle volume distribution and separation efficiency were investigated according to the two objectives of NGH recovery efficiency and sand removal efficiency with different inlet velocities by computational fluid simulations (CFD)-FLUENT software. The results show that the short circuit flow contributed to the recovery of NGH. Axial velocity is a decisive factor in balancing the two objectives of NGH recovery efficiency and sand removal efficiency. In addition, the same as those in traditional hydrocyclones, the static pressure, tangential velocity and turbulence intensity play key roles in separation performance, hydrocyclone performance can be improved by increasing the inlet velocity. On the other hand, most separation efficiencies were greater than 80%, when the particle size was larger than 15 µm, and the differential pressure was less than 0.6 MPa. Therefore, all the above results confirm that hydrocyclone has good performance in NGH exploitation, and the basis of its structural design and optimization are provided.

The Comparison with Numerical Simulation Results of Steam-Water Flow Field and Experimental Data for Car Exhaust Pipe

2011 ◽  
Vol 187 ◽  
pp. 570-574
Author(s):  
Qing Guo Liu ◽  
Yan Ma ◽  
Chun Mei Yang
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Flow Field ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Exhaust Pipe ◽  
Two Phase ◽  
Car Exhaust ◽  
Simulation Results ◽  
The Relationship

In this paper, the physical model for flow field of exhaust pipe has been established on the condition of a liquid-gas exhaust pipe from cars using ethanol gasoline. The numerical simulation results for internal flow field of car exhaust pipe are compared with the experimental data. It is showed that the outside free vortex tangential velocity and axial velocity of single-phase flow field have been simulated better. It is indicated in the simulation of separation process of steam-water two-phase: The relative error, comparing the relationship between flow and separation efficiency with measured of that is less than 7%, and the same to 15%, comparing the relationship between flow and separation ratio with measured of that. Thereby, it is confirmed correctly for the mathematical model founded for numerical calculation and the algorithm selected.

Numerical Simulation of Gas Flow Field in Gas-Liquid Hydrocyclone Separator

2011 ◽  
Vol 109 ◽  
pp. 509-516
Author(s):  
Xiang Hong Jin ◽  
Feng Shuang Han ◽  
Jin Liang Zhang ◽  
Hui Huang ◽  
Xin Wen Liu
Keyword(s):  
Flow Field ◽  
Gas Flow ◽  
Separation Efficiency ◽  
Short Circuit ◽  
Tangential Velocity ◽  
Flow Distribution ◽  
Mouth Area ◽  
Exhaust Pipe ◽  
Outlet Angle ◽  
Gas Flow Field

The gas flow field in hydrocyclone separator was numerically simulated by applying RSM turbulence model, and the gas flow velocity distribution and stress distribution were calculated. According to the characteristics of gas flow distribution within the separator, it is found that: (1) the rotating strength of gas flow is related to the outlet angle of guide blade, the greater the outlet angle, the smaller the tangential velocity; (2) the obvious short circuit flow distribution under the exhaust pipe mouth area is easy to carry droplets and roll them out, causing a decrease in separation efficiency; (3) the high strength of turbulence pulse at mouth area of vent and drainage is easy to break the droplets and decrease their diameter, which affects the separation efficiency. The above research results lay the foundation for the structure optimization and the improvement of separation properties of axial guide vane cyclone gas-liquid separator.

Field testing CFD-based predictions of storage chamber gross solids separation efficiency

1999 ◽  
Vol 39 (9) ◽  
pp. 161-168 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul ◽  
Andrew Drinkwater ◽  
Ian Clifforde
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Settling Velocity ◽  
Separation Efficiency ◽  
Flow Patterns ◽  
Total Efficiency ◽  
Separation Performance ◽  
Storage Chamber ◽  
Solids Separation ◽  
Simulated Flow

The use of computational fluid dynamics-based techniques for predicting the gross solids and finely suspended solids separation performance of structures within urban drainage systems is becoming well established. This paper compares the result of simulated flow patterns and gross solids separation predictions with field measurements made in a full size storage chamber. The gross solids retention efficiency was measured for six different storage chambers in the field and simulations of these chambers were undertaken using the Fluent computational fluid dynamics software. Differences between the observed and simulated flow patterns are discussed. The simulated flow fields were used to estimate chamber efficiency using particle tracking. Efficiency results are presented as efficiency cusps, with efficiency plotted as a function of settling velocity. The cusp represents a range of efficiency values, and approaches to the estimation of an overall efficiency value from these cusps are briefly discussed. Estimates of total efficiency based on the observed settling velocity distribution differed from the measured values by an average of ±17%. However, estimates of steady flow efficiency were consistently higher than the observed values. The simulated efficiencies agreed with the field observations in identifying the most efficient configuration.

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