scholarly journals Simulation and Experiment of Gas-Solid Flow in a Safflower Sorting Device Based on the CFD-DEM Coupling Method

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1239
Author(s):  
Zhizheng Hu ◽  
Haifeng Zeng ◽  
Yun Ge ◽  
Wendong Wang ◽  
Jiangkun Wang
Keyword(s):  
Loss Rate ◽  
Process Integration ◽  
Coupling Method ◽  
Particle Model ◽  
Separation Mechanism ◽  
Airflow Velocity ◽  
Ansys Fluent ◽  
Inclination Angles ◽  
Set Up ◽  
Inclined Angle

To study the movement characteristics and separation mechanism of safflower petals and their impurities under the action of airflow and lower the impurity rate in the cleaning operation process, integration of computational fluid dynamics (CFD) and discrete element method (DEM) codes was performed to study the motion and sorting behavior of impurity particles and safflower petals under different airflow inclination angles, dust removal angles and inlet airflow velocities by establishing a true particle model. In this model, the discrete particle phase was applied by the DEM software, and the continuum gas phase was described by the ANSYS Fluent software. The Box-Behnken experimental design with three factors and three levels was performed, and parameters such as inlet airflow velocity, airflow inclined angle, and dust remover angle were selected as independent variables that would influence the cleaning impurity rate and the cleaning loss rate. A mathematical model was established, and then the effects of various parameters and their interactions were analyzed. The test results show that the cleaning effect is best when the inlet airflow velocity is 7 m/s, the airflow inclined angle is 0°, and the dust remover angle is 25°. Confirmatory tests showed that the average cleaning impurity rate and cleaning loss rate were 0.69% and 2.75%, respectively, which dropped significantly compared with those from previous optimization. An experimental device was designed and set up; the experimental results were consistent with the simulation results, indicating that studying the physical behavior of safflower petals-impurity separation in the airflow field by using the DEM-CFD coupling method is reliable. This result provides a basis for follow-up studies of separation and cleaning devices for lightweight materials such as safflower petals.

Numerical Simulation of Electrohydrodynamic (EHD) Atomization in the Cone-Jet Mode

2013 ◽  
Vol 325-326 ◽  
pp. 180-185 ◽  
Author(s):  
Abdolkarim Najjaran ◽  
Reza Ebrahimi ◽  
Morteza Rahmanpoor ◽  
Ahmad Najjaran
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Ambient Temperature ◽  
Deposition Rate ◽  
Low Cost ◽  
High Deposition Rate ◽  
Deposition Technique ◽  
Enhanced Heat Transfer ◽  
Ansys Fluent ◽  
Set Up

Electrohydrodynamic (EHD) has been applied in many areas, such as EHD atomization, EHD enhanced heat transfer, EHD pump, electrospray nanotechnology, etc. EHD atomization is a promising materials deposition technique as it allows uniform and regular deposition, and offers a range of other advantages, such as low cost compared with other current techniques, easy set-up, high deposition rate, and ambient temperature. Simulation is carried out using ANSYS FLUENT system. The approach in this work was to simultaneously solve the coupled (EHD) and electrostatic equations. The fields of velocities and pressure, as well as electric characteristics of EHD flows, are calculated. The model does not include a droplet break-up model.

scholarly journals Multi-Aspect Comparison of Ethyl Acetate Production Pathways: Reactive Distillation Process Integration and Intensification via Mechanical and Chemical Approach

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1618
Author(s):  
Branislav Šulgan ◽  
Juraj Labovský ◽  
Zuzana Labovská
Keyword(s):  
Ethyl Acetate ◽  
Case Studies ◽  
Chemical Reaction ◽  
Distillation Column ◽  
Reactive Distillation ◽  
Process Integration ◽  
Distillation Process ◽  
Acetate Production ◽  
Conventional Process ◽  
Set Up

This paper provides a multi-aspect comparison of selected methods of ethyl acetate production and shows the possibility of further reactive distillation process integration and sophisticated intensification including process stream regeneration. The production pathways were selected with respect to their practical applicability and sufficient experimental and feasibility studies already published. A total of four case studies were designed and compared: conventional process set-up (ethyl acetate is produced in a chemical reactor) is designed as a base case study; reactive distillation with a separation unit is derived from the conventional process set-up. The mechanical and chemical approach to reactive distillation process intensification and integration were assumed: reactive distillation column with a stripper and reactive distillation column with an auxiliary chemical reaction (ethylene oxide hydration). Process models were compiled in the Aspen Plus software. Complex process flowsheets of selected case studies including separation and regeneration were designed and optimized. Three different points of view were applied to evaluate the selected process benefits and drawbacks. Process energy, economy, and safety were assessed. As a result, a reactive distillation column with an auxiliary chemical reaction has been proven to be the most suitable pathway for ethyl acetate production assuming all three evaluated aspects.

scholarly journals A Hybrid BEM-CFD Virtual Blade Model to Predict Interactions between Tidal Stream Turbines under Wave Conditions

2020 ◽  
Vol 8 (12) ◽  
pp. 969
Author(s):  
Nicolo’ Lombardi ◽  
Stephanie Ordonez-Sanchez ◽  
Stefania Zanforlin ◽  
Cameron Johnstone
Keyword(s):  
Numerical Study ◽  
Experimental Tests ◽  
Full Scale ◽  
Small Scale ◽  
Ansys Fluent ◽  
Narrow Channels ◽  
Tidal Turbine ◽  
Performance Deterioration ◽  
Set Up ◽  
Blade Model

Tidal turbine array optimization is crucial for the further development of the marine sector. It has already been observed that tidal turbines within an array can be heavily affected by excessive aerodynamic interference, thus leading to performance deterioration. Small-scale experimental tests aimed at understanding the physical mechanisms of interaction and identifying optimal distances between machines can be found in the literature. However, often, the relatively narrow channels of laboratories imply high blockage ratios, which could affect the results, making them unreliable if extrapolated to full-scale cases. The main aim of this numerical study was to analyze the effects of the blockage caused by the laboratory channel walls in cases of current and also current surface waves. For this purpose, the performance predictions achieved for two turbines arranged in line for different lateral offsets in case of a typical laboratory scale were compared to the predictions obtained for a full scale, unconfined environment. The methodology consisted in the adoption a hybrid Blade Element Momentum–Computational Fluid Dynamics (BEM-CFD) approach, which was based on the Virtual Blade Model of ANSYS-Fluent. The results indicate that (1) the performance of a downstream turbine can increase up to 5% when this has a lateral separation of 1.5D from an upstream device in a full-scale environment compared to a misleading 15% calculated for the laboratory set-up, and (2) the relative fluctuations of power and thrust generated by waves are not significantly affected by the domain dimensions.

Efficiency of Scrap Rubber Particles on Strength of Cementitious Materials

2011 ◽  
Vol 374-377 ◽  
pp. 1374-1379 ◽  
Author(s):  
Guang Cheng Long ◽  
Zhe Li ◽  
You Jun Xie
Keyword(s):  
Loss Rate ◽  
Rubber Particle ◽  
Hydrophobic Effect ◽  
Research Programme ◽  
Strength Loss ◽  
Cementitious Materials ◽  
Mortar Sample ◽  
Deformation Effect ◽  
Rubber Particles ◽  
Set Up

An extensive research programme was set up to investigate the efficiency of scrap rubber particles on strength of cementitious materials. The index of strength loss rate of paste and mortar sample caused by increasing 1% volume rubber particles was proposed to analyze the efficiency of rubber particles in cementitious materials. And the corresponding mechanism was also discussed in this paper. Results indicate that in the investigated area, the loss rate in compressive strength both for paste and mortar almost ranges from 2% to 5% caused by increasing 1% rubber particles depending on the total volume of rubber particle added into sample. However, the loss rate in flexural strength of mortar by increasing 1% volume rubber particles is obviously different from that. Three roles of scrap rubber particles played in cementitious materials, named as deformation effect, equivalent-pore effect and hydrophobic effect, are responsible for the efficiency of scrap rubber particles on strength of cementitious material. The efficiency of rubber particles on strength of paste and mortar differs from each other due to the different microstructure between paste and mortar.

Effect of inclination on the transition scenario in the wake of fixed disks and flat cylinders

2015 ◽  
Vol 770 ◽  
pp. 189-209 ◽  
Author(s):  
M. Chrust ◽  
C. Dauteuille ◽  
T. Bobinski ◽  
J. Rokicki ◽  
S. Goujon-Durand ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Numerical Simulations ◽  
Vortex Shedding ◽  
Flow Direction ◽  
Transition To Turbulence ◽  
Inclination Angles ◽  
Set Up ◽  
Transition Scenario ◽  
Small Inclination

We take up the old problem of Calvert (J. Fluid Mech., vol. 29, 1967, pp. 691–703) concerning the wake of a cylinder inclined with respect to the flow direction, and consider it from the viewpoint of transition to turbulence. For cylinders placed perpendicular to the flow direction, we address the disagreement between numerical simulation of the ideal axisymmetric configuration and experimental observations. We demonstrate that for a disk (a cylinder of aspect ratio infinity) and a flat cylinder of aspect ratio ${\it\chi}=6$ (ratio of diameter to height), the numerically predicted transition scenario is limited to very small inclination angles and is thus difficult to test experimentally. For inclination angles of about $4^{\circ }$ and more, a joint numerical and experimental study shows that the experimentally observed scenario agrees qualitatively well with the results of numerical simulations. For the flat cylinder ${\it\chi}=6$, we obtain satisfactory agreement with regard to dependence of the critical Reynolds number ($\mathit{Re}$) of the onset of vortex shedding on the inclination angle. Both for infinitely flat disks and cylinders of aspect ratio ${\it\chi}=6$, a small inclination tends to promote vortex shedding, that is, to lower the instability threshold, whereas for inclination angles exceeding $20^{\circ }$ the opposite effect is exhibited. The Strouhal number of oscillations is found to be only very weakly dependent on the Reynolds number, and very good agreement is obtained between values reported by Calvert (J. Fluid Mech., vol. 29, 1967, pp. 691–703) at high Reynolds numbers and our simulations at $\mathit{Re}=250$. In contrast, we observe relatively poor agreement in Strouhal numbers when comparing the results of our numerical simulations and the data acquired from the experimental set-up described in this paper. Closer analysis shows that confidence can be placed in the numerical results because the discrepancy can be attributed to the influence of the support system of the flat cylinder. Suggestions for improvement of the experimental set-up are provided.

scholarly journals Earth Air Tunnel Heat Exchanger for Building Cooling and Heating

2021 ◽  
Author(s):  
Nasim Hasan ◽  
Mohd Arif ◽  
Mohaideen Abdul Khader
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Numerical Algorithms ◽  
Ansys Fluent ◽  
Helical Pipe ◽  
Complex Fluid ◽  
Set Up ◽  
Building Cooling

The computational fluid dynamic (CFD) is an influential method for measuring Heat transfer profiles for typical meteorological years. CFD codes are managed by numerical algorithms that may undertake fluid glide headaches. CFD offers the numerical results of partial differential equations with main airflow and heat transfer in a discretized association. The complex fluid glide and the warmth transfer publications worried in any heat exchanger can be determined with the help of the CFD software program (Ansys Fluent). A study states and framework which implicitly rely on the computational fluid dynamics, which is being formulated for computing the efficiency-related parameters of the thermal part and the capability of the EATHE system for cooling. A CFD simulation program is being used for modeling the system. The framework is being validated with the help of the simulation set-up. A thermal model was developed to analyze thermal energy accumulated in soil/ground for the purpose of room cooling/heating of buildings in the desert (hot and dry) climate of the Bikaner region. In this study, the optimization of EATHE design has been performed for finding the thermal performance of straight, spiral, and helical pipe earth air tunnel heat exchanger and Heat transfer rate for helical pipe was found maximum among all designs.

scholarly journals Photo-absorption and electron collection of field-assisted GaN nanohole array photocathode

2021 ◽  
Author(s):  
Lei Liu ◽  
Feifei Lu ◽  
Jian Tian ◽  
Xingyue Zhangyang
Keyword(s):  
Light Absorption ◽  
Continuity Equation ◽  
Filling Factor ◽  
Collection Efficiency ◽  
Three Dimensional ◽  
Nanohole Array ◽  
Electron Collection ◽  
Planar Film ◽  
Inclination Angles ◽  
Inclined Angle

Abstract The light absorption and photo-generation rate under different periods, filling factors (FF), hole depth and inclination angles are studied. The NHA exhibits a larger light absorption compared with the planar film, which is about 99.99973%. Based on the three-dimensional continuity equation, the quantum efficiency (QE) and collection efficiency (CE) of the field-assisted GaN NHA and the graded compositional AlGaN NHA are calculated. The QE and CE of the GaN NHA with a period of 200 nm, a filling factor of 0.05, an inclined angle of 10°, and a field intensity of 2 V/µm are 62.7% and 62.6%, respectively. In addition, the graded compositional AlGaN structure has a more improved effect on the vertical NHA. Compared with the uniform GaN NHA, the electron collection of AlGaN NHA ratio is increased by 2.4 times. The design principles proposed in this work provide guidance to reasonable parameters for the application of NHA photocathodes.

Experimental and Numerical Study on Natural Circulation Under Inclined Condition

2013 ◽  
Author(s):  
Hongye Zhu ◽  
Xingtuan Yang ◽  
Haibo Lian ◽  
Shengyao Jiang
Keyword(s):  
Flow Resistance ◽  
Numerical Study ◽  
Natural Circulation ◽  
Large Angle ◽  
Cfd Model ◽  
Small Width ◽  
Small Loop ◽  
Set Up ◽  
Inclined Angle ◽  
Total Circulation

Natural circulation systems are broadly used in marine environments. When accidents happen, these systems may work under inclined condition. In this paper, we conducted a series of experimental study on the thermohydraulics behavior of natural circulation in a symmetric two-circuit loop under the inclined angle from 0∼45°. A CFD model is also set up and predicts the results well in comparing with the experiments. Both experimental and numerical analysis show that with the increase of inclined angle, the total circulation flow rate decreases. When the loop inclines about the axis perpendicular to the circulation, one circulation is depressed while the other is enhanced; accordingly the disparity between the branch circulations arises and increases with the increase of inclined angle. The flow pattern of the circulation under larger inclined angle (45∼90°) condition is also studied by CFD model. At large inclined angle the circulation is mainly happens in one circuit. Also based on this model, the influences of flow resistance distribution and loop configuration on natural circulation are predicted. The numerical results show that to design the loop with the configuration of big altitude difference and small width are favorable to confine the influence of inclination; however too small loop width will cause sever reduction of circulation ability in large angle inclination.

Sorting Mechanism and Airflow Simulation of Garbage Pneumatic Separator

2011 ◽  
Vol 148-149 ◽  
pp. 297-300
Author(s):  
Wei Kang Li ◽  
Shuo Yang ◽  
Xin Le Yang
Keyword(s):  
Theoretical Foundation ◽  
Mathematic Model ◽  
Flow Rule ◽  
Separation Mechanism ◽  
Two Phase ◽  
Fluent Software ◽  
And Performance ◽  
Set Up ◽  
Stable Variation ◽  
Back Mixing

In order to obtain flow rule and separation mechanism of garbage mixture particle in pneumatic separator, under the conditions of certain parameters and boundary, gas-solid two-phase flow mathematic model of garbage mixture particle was set up, FLUENT software was used to simulation and analyze the flow field of improved pneumatic separator, the separate track of particle in improved pneumatic separator was gained and performance of improved pneumatic separator was forecasted. Numerical simulation results show that the improved pneumatic separator has stable variation of pressure and velocity field. There not exist internal turbulence and back-mixing phenomenon and three particles with different qualities can be separated effectively. The numerical methods can be further optimized pneumatic separator and important theoretical foundation and technology method are provided for improving the structure and performance of pneumatic separator.

Parameters Optimization of Turning Free Cutting Steel Based on the Coupling Method of Response Surfaces

2011 ◽  
Vol 188 ◽  
pp. 301-306 ◽  
Author(s):  
Zhi Qiang Liu ◽  
Xiao Jiang Cai ◽  
Shu Han ◽  
Ming Chen ◽  
Qing Long An
Keyword(s):  
Cutting Parameters ◽  
Response Surfaces ◽  
Parameters Optimization ◽  
Coupling Method ◽  
Optimal Selection ◽  
Turning Process ◽  
Processing Efficiency ◽  
Cutting Steel ◽  
Set Up ◽  
Made In

Turning parameters are subject to processing efficiency, cutting force and surface quality, etc. A method, called the coupling method of response surfaces, is presented in this paper to select cutting parameters subjected to several constraints. An experiment of turning free cutting steel is made in order to set up the model. The results from the optimal selection provide a basis prototype for the cutting parameters. It can meet the needs of the turning process in industrial production.

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