Study on Separation Performance of Gas-Liquid Cyclone Separator with Pulsating Feeds

Author(s):  
Guangrong Lu ◽  
Yongjun Hou ◽  
Xianjin Wu ◽  
Hang Wu ◽  
Rui Jiang ◽  
...  

Background: In recent years, a kind of drilling method of Solid-Liquid separation combined with pulsating vacuum formed by vibrating screen and compressed air injection has emerged in oil drilling, which greatly improves the gas, solid and liquid separation ability of the drilling fluid vibration screen. Objective: Based on the above ideas, a kind of hydrocyclone used for gas-liquid separation with the pulsating feed boundary was proposed. The separation performance of gas-liquid hydrocyclone may change greatly due to the mixed pulsation of the gas-liquid fluid transported by the jet pump. Therefore, the flow characteristics of the pulsating feed hydrocyclone need to be analyzed and explored to provide basic data for further improvement of structure. Methods: The development status of cyclone separators are summarized through related literatures and patents investigation. The Computational Fluid Dynamics (CFD) software ANSYS Fluent 2019 R3 is used to analyze the flow field characteristics and optimize the parameters of the hydrocyclone with stable feed. Then, programming by the User-Define-Function (UDF) of Fluent is used to simulate the flow field of the separator under the condition of pulsating feed, meanwhile, the flow field analysis and parameter optimization are carried out accordingly. Results: The optimal parameters in stable state and pulsed state are obtained through the analysis of efficiency curve. The results show that the flow field can be stabilized in the pulsating feed state, and the sinusoidal pulsing with a frequency of 0.4Hz is used to achieve the highest separation efficiency, reaching 85.5%. Conclusion: The separators with pulsating feed and stable feed have similar flow field characteristics, and the optimal structural parameters under pulsating feed are obtained. Compared with the stable feed condition, the pulsating feed condition can connect multiple cyclone separators, which can separate more drilling fluid in unit time, and the work efficiency could be improved. It has a strong practicability, which provides an important basis for the structure optimization in future.

Separations ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 79
Author(s):  
Yuekan Zhang ◽  
Jiangbo Ge ◽  
Lanyue Jiang ◽  
Hui Wang ◽  
Junru Yang ◽  
...  

In view of the difficulty of traditional hydrocyclones to meet the requirements of fine classification, a double-overflow three-product (internal overflow, external overflow and underflow) hydrocyclone was designed in this study. Numerical simulation and experimental research methods were used to investigate the effects of double-overflow flow field characteristics and structural parameters (i.e., internal vortex finder diameter and insertion depth) on separation performance. The research results showed that the larger the diameter of the internal vortex finder, the greater the overflow yield and the larger the cut size. The finest internal overflow product can be obtained when the internal vortex finder is 30 mm longer than the external vortex finder. The separation efficiency is highest when the internal vortex finder is 30 mm shorter than the external vortex finder.


2014 ◽  
Vol 685 ◽  
pp. 127-132
Author(s):  
Qing Zhang ◽  
Bo Yu ◽  
Yu Liu

In order to evaluate the separation efficiency of each module in this type of novel combined separator, by PDPA(Phase Doppler Particle Analyzer) we find that under different conditions in 6 combinations, combination 6 (including cyclone + stabilizer + blade+ baffler) has the highest separation efficiency, and there are relatively efficiency valley region in all the 6 combinations. Under the same conditions, the average separation efficiency of the baffler is higher than the blade, and then the blade and baffler have their own advantages in different flowrate. To use stabilizer can effectively improve the flow field inside the separator, restrain and reduce vortex and backmixing, more conductive to the gas-liquid separation.


Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Junfeng Sun ◽  
Meihong Liu ◽  
Zhen Xu ◽  
Taohong Liao ◽  
Xiangping Hu ◽  
...  

A new type of cylindrical gas film seal (CGFS) with a flexible support is proposed according to the working characteristics of the fluid dynamic seal in high-rotational-speed fluid machinery, such as aero-engines and centrifuges. Compared with the CGFS without a flexible support, the CGFS with flexible support presents stronger radial floating characteristics since it absorbs vibration and reduces thermal deformation of the rotor system. Combined with the structural characteristics of a film seal, an analytical model of CGFS with a flexible wave foil is established. Based on the fluid-structure coupling analysis method, the three-dimensional flow field of a straight-groove CGFS model is simulated to study the effects of operating and structural parameters on the steady-state characteristics and the effects of gas film thickness, eccentricity, and the number of wave foils on the equivalent stress of the flexible support. Simulation results show that the film stiffness increases significantly when the depth of groove increases. When the gas film thickness increases, the average equivalent stress of the flexible support first decreases and then stabilizes. Furthermore, the number of wave foils affects the average foils thickness. Therefore, when selecting the number of wave foils, the support stiffness and buffer capacity should be considered simultaneously.


2013 ◽  
Vol 477-478 ◽  
pp. 191-196
Author(s):  
Yu Bao Gao ◽  
Wei Hong Zhou ◽  
Lu Shan Cen ◽  
Yu Cong Xu ◽  
Jiu Xing Liang ◽  
...  

Multi-layers parallel plates perfusion bioreactor has the potential advantage in cells cultivation of tissue engineering and good scalability for cells cultivation on a large scale. It is necessary to analyze the distribution of flow shear stress (FSS) of bioreactors which has strong influence on the growth of cells. The result of meshing was not satisfactory because of the complexity of multi-layers parallel plates when using computational fluid dynamics (CFD) to analyze the FSS, and the amount of calculation was great and complex especially under the process of influence on FSS caused by analyzing the different structure. The new method of simplified flow field analysis was presented in this paper, which was based on relation between FSS and flow and made the process simpler by analyzing distribution of rate instead of FSS. The simulation result showed that this method can satisfy the requirement of precision and provide reference for the analysis of the flow field which had the established relationship between structural parameters and laminar flow within it.


2013 ◽  
Vol 275-277 ◽  
pp. 558-561
Author(s):  
Xiao Ming Yuan ◽  
Hui Jun Zhao ◽  
Jing Yi Qu

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.


Author(s):  
Abdul Motin ◽  
Volodymyr V. Tarabara ◽  
André Bénard

This research addresses various hydrodynamic aspects and the separation performance of a novel cross-flow filtration hydrocyclone (CFFH) using computational fluid dynamics. A CFFH is a device that combines the desirable attributes of a cross-flow filter and a vortex separator into one unit to separate oil from water. The velocity and pressure fields within the CFFH are estimated by numerically solving the filtered Navier-Stokes equations (by using a Large Eddy Simulation (LES) approach). The Lagrangian approach is employed for investigating the trajectories of dispersed droplets based on a stochastic tracking method called the Discrete Phase Model (DPM). The mixture theory with the Algebraic Slip Model (ASM) is also used to compute the dispersed phase fluid mechanics and for comparing with results obtained from the DPM. In addition, a comparison between the statistically steady state results obtained by the LES with the Wall Adaptive Local Eddy-Viscosity (WALE) subgrid scale model and the Reynolds Average Navier-Stokes (RANS) closed with the Reynolds Stress Model (RSM) is performed for evaluating their capabilities with regards to the flow field within the CFFH and the impact of the filter medium. Effects of the Reynolds number, the permeability of the porous filter, and droplet size on the internal hydrodynamics and separation performance of the CFFH are investigated. Results indicate that for low feed concentration of the dispersed phase, separation efficiency obtained based on multiphase and discrete phase simulations is almost the same. Higher Reynolds number flow simulations exhibit an unstable core and thereby numerous recirculation zones in the flow field are observed. Improved separation efficiency is observed at a lower Reynolds number and for a lower permeability of the porous filter.


2021 ◽  
Vol 163 (A1) ◽  
pp. 63-77
Author(s):  
C An ◽  
C W Gu ◽  
H Qin ◽  
T T Li ◽  
M L Duan

In this paper, a simplified model for erosion in un-bonded flexible pipes caused by the sand entrained in the produced fluid is established. Flow field analysis is performed based on the governing equations of the continuous fluid and the discrete particles. A two-way coupled Eulerian-Lagrangian approach is employed to solve the gas-solid flow in the pipe bend. To eliminate the influence of the length of the straight pipe section on the stability of the flow field in the pipe, the flow field distribution under different lengths is analyzed to determine the optimal straight pipe length. Six commonly used erosion models are adopted to predict the erosion rate. After comparing the prediction results with experimental data, the most accurate Oka model is selected to calculate the effect of the fluid and structure parameters on erosion. Effects of particle parameters and pipe structural parameters on the erosion rate of curved flexible pipes are numerically fitted, and the quantitative description is given.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Juyue Ding ◽  
Weitan Yin ◽  
Yongqi Ma

As more long-span bridges continue to be completed and opened to traffic, the safety of cars driving across the bridge has attracted more and more attention, especially when the car is suddenly affected by the crosswind, the car is likely to have direction deviation or even a rollover accident. In this paper, the large eddy simulation method is used to study the flow field characteristics and safety of the car on the bridge under the turbulent crosswind. The numerical simulation model is established by referring to the Donghai Bridge, and the correctness of the car model is validated by combining with the data of wind tunnel test. The influence of factors such as the porosity and height of the bridge guardrail and the Reynolds number of airflow on the flow field characteristics is analyzed. The study shows that, in order to ensure the safety of cars on the bridge, the bridge guardrail porosity should be small, 35.8% is more suitable, the guardrail height should be more suitable within the range of 1.5–1.625 meters, and the Reynolds number should not be 3.51e + 5. The research results of this paper will provide reference for the optimal design of bridge guardrail.


2011 ◽  
Vol 422 ◽  
pp. 794-798
Author(s):  
Xue Ping Wang ◽  
Ying Zhang ◽  
Ju Guang Xue ◽  
Zhen Wei Zhang

The numerical simulation can be obtained by taking advantage of turbulence model of Fluent to study the gas-solid flow field of cyclone separator. The pressure of the cyclone drops increases with the enhancement of the inlet flow velocity, and the increase amplitude can become larger and larger. The separation efficiency of the cyclone enhances gradually as the increase of the flow. The increase amplitude of small and secondary particles is much lager compared with the increase amplitude of big ones. The overall separation efficiency can strengthen gradually with increasing of particles concentration as well as the each part’s efficiency. But the separation efficiency will stay in stable level when the concentration reaches a certain value with the big particles in the low concentration and small ones in a relatively high concentration.


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