The Experts below are selected from a list of 4359 Experts worldwide ranked by ideXlab platform
Atakan Avci - One of the best experts on this subject based on the ideXlab platform.
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performance analysis of axial and reverse flow Cyclone Separators
Chemical Engineering and Processing, 2019Co-Authors: Ali Sakin, Irfan Karagoz, Atakan AvciAbstract:Abstract Performance characteristics of a novel Cyclone with tangential inlet were presented in axial and reverse flow operation modes. 3-D and unsteady governing equations were used for the numerical solution of the two-phase turbulent flow in the Cyclone separator. The Eulerian approach was used to solve the flow field, and the Reynolds Stress Model (RSM) with the scalable wall function was employed for the numerical study. The Lagrangian approach with the Discrete Phase Model was used to calculate the discrete phase by releasing particles from the inlet surface. CFD calculations were run for different geometric configurations to analyze the performance of the Cyclones regarding pressure drop, cut-off diameter, and fractional efficiency. Axial and tangential velocity profiles are presented at the defined sections. The computational results of pressure drop, velocity field, and separation efficiency were also compared for the axial and reverse flow Cyclones at the same flow rate. The results show that pressure drop and collection efficiency in reverse flow mode are higher than that of the axial flow operation. However, axial flow Cyclones seem to be more efficient for small particles comparing to reverse flow Cyclones.
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effects of surface roughness on the performance of tangential inlet Cyclone Separators
Aerosol Science and Technology, 2011Co-Authors: Fuat Kaya, Irfan Karagoz, Atakan AvciAbstract:This study is carried out to investigate the effects of surface roughness on the flow field and Cyclone performance. The flow inside the Cyclone separator is modeled as a three-dimensional turbulent continuous gas flow with solid particles as a discrete phase. The continuous gas flow is predicted by solving the governing equations by using the Reynolds Stress turbulence model, and the modeling of the particle motions is based on a Lagrangian approach. The results of the numerical simulations are compared with experimental data as well as with the results of mathematical models. Analysis of computed results shows that increase of relative roughness due to corrosion, wear, or accumulation of particles on the inner walls considerably influences the tangential velocity, Cyclone separation efficiency, and Cyclone pressure drop especially for high inlet velocities. Decreases in Cyclone collection efficiency and pressure drop with the increase in surface roughness are found to be more pronounced for high values ...
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usability of Cyclone Separators as air filters in vehicles
International Journal of Vehicle Design, 2010Co-Authors: Irfan Karagoz, Fuat Kaya, Atakan AvciAbstract:This study deals with the use of Cyclone Separators as air filters in light or heavy duty vehicles. Cyclone Separators were compared with the conventional air filters, which provide low particle collection efficiency with high pressure drop, and these characteristics are made worse by contamination. By taking into account the related studies in the literature, tangential inlet Cyclones were considered in this comparison. The pressure drop and particle collection efficiency in the proposed tangential inlet Cyclone were computed by using the mathematical models given in the literature. Comparison of the computed results of the Cyclone with the conventional air filters demonstrated that the tangential inlet Cyclones are advantageous because of low pressure drop and high particle collection efficiency and can be used as main or pre-filters in vehicles.
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modelling of the pressure drop in tangential inlet Cyclone Separators
Aerosol Science and Technology, 2005Co-Authors: Irfan Karagoz, Atakan AvciAbstract:This article introduces a new mathematical model that predicts the pressure drop in a tangential inlet Cyclone. The model calculates the pressure drop from the frictional losses in the Cyclone body, using a wall friction coefficient based on the surface roughness and Reynolds number. The entrance and exit losses are also included in the model by defining new geometrical parameters. The pressure drop coefficient is obtained as a function of Cyclone dimensions and operating conditions. The model is validated by studying 12 different Cyclones presented in the literature. Comparison of the model results with predictions and measurements published in the literature show that the new model predicts the experimental results quite well for a wide range of operating conditions covering a flow rate of 0.3–220 l/s and a temperature range of 293–1200°K, in different Cyclones. The pressure drop coefficient is also examined in view of the outlet pipe diameter, friction coefficient, surface roughness, and Reynolds number.
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effects of flow and geometrical parameters on the collection efficiency in Cyclone Separators
Journal of Aerosol Science, 2003Co-Authors: Atakan Avci, Irfan KaragozAbstract:A mathematical model has been developed for calculation of cut-off size and fractional efficiencies in Cyclone Separators, by taking into account the effects of flow, particle and geometrical parameters, and acceleration assuming that the mixture of fluid and particles is homogenous, and acceleration diminishes depending on the friction and geometry. Collection efficiency curves and cut-off size values predicted by the proposed model showed a good agreement with experiments over a wide range of inlet velocities for different types of Cyclones. Comparison of the obtained results with semi empirical models available in literature also indicated that the present model may be used successfully for determination of the performance of a tangential inlet Cyclone. Analyses of the effects of various parameters reveals that, in addition to flow and geometrical parameters, surface friction, vortex length and flow regimes play an important role on Cyclone performance especially in small Cyclones.
Bingtao Zhao - One of the best experts on this subject based on the ideXlab platform.
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artificial neural network based modeling of pressure drop coefficient for Cyclone Separators
Chemical Engineering Research & Design, 2010Co-Authors: Bingtao Zhao, Yaxin SuAbstract:In order to build the complex relationships between Cyclone pressure drop coefficient (PDC) and geometrical dimensions, representative artificial neural networks (ANNs), including back propagation neural network (BPNN), radial basic functions neural network (RBFNN) and generalized regression neural network (GRNN), are developed and employed to model PDC for Cyclone Separators. The optimal parameters for ANNs are configured by a dynamically optimized search technique with cross-validation. According to predicted accuracy of PDC, performance of configured ANN models is compared and evaluated. It is found that, all ANN models can successfully produce the approximate results for training sample. Further, the RBFNN provides the higher generalization performance than the BPNN and GRNN as well as the conventional PDC models, with the mean squared error of 5.84 × 10−4 and CPU time of 120.15 s. The result also demonstrates that ANN can offer an alternative technique to model Cyclone pressure drop.
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Modeling pressure drop coefficient for Cyclone Separators: A support vector machine approach
Chemical Engineering Science, 2009Co-Authors: Bingtao ZhaoAbstract:Abstract As one of performance critics for Cyclone Separators, pressure drop is an important parameter to evaluate and design Cyclone Separators. In order to accurately predict the complexly nonlinear relationships between pressure drop coefficient (PDC) and geometrical dimensions, a support vector machine (SVM) model is developed and employed to model PDC for Cyclone Separators. Based on the normalization method and the random sampling technique for the experimental sample dataset, a dynamically optimized search technique with cross validation is introduced to determine optimal algorithm parameters in the model. Then the optimized SVM model is trained and tested by the simulation results. According to the predicted accuracy of PDC for Cyclone Separators, the SVM model performance is compared and evaluated. It is found that the SVM model provides the higher generalization performance than the conventional models including the theoretical and statistical models as well as the artificial neural network model, with the mean squared error of 3.64×10−4 and the correlation coefficient of 0.9974. The result also demonstrates that SVM can offer an alternative and powerful approach to model Cyclone pressure drop.
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particle collection theory for Cyclone Separators summary and comparison
Particle & Particle Systems Characterization, 2006Co-Authors: Bingtao Zhao, Yaxin SuAbstract:The current status of the development of the particle collection theory for Cyclone Separators, including the theories of equilibrium-orbit, time-of-flight, hybrid and CFD (Computational Fluid Dynamics), is summarized in this paper. In order to evaluate their predictive availability, several gas-particle separation models representing the different approaches for calculation of the collection in a Cyclone, are compared with the grade efficiency curves generated from experimental measurements. The results show that both the Mothes and Loffler and Iozia and Leith theories can perform better in the semi-empirical theory, and also demonstrate that the CFD theory is a more fundamental and basic method, which is capable of modeling the particle collection in Cyclone Separators.
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Experimental Investigation of Flow Patterns in Cyclones with Conventional and Symmetrical Inlet Geometries
Chemical Engineering & Technology, 2005Co-Authors: Bingtao ZhaoAbstract:The gas flow patterns in two different Cyclone Separators with conventional and symmetrical inlet geometries are analyzed and compared. Based on the results of experimental investigations of tangential velocity, axial velocity and static pressure distribution in these Separators, the similarities and differences between the flow patterns are discussed. Furthermore, the influence of the inlet geometry on the flow patterns as well as the mechanism of gas-particle separation and pressure drop are evaluated.
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A Theoretical Approach to Pressure Drop across Cyclone Separators
Chemical Engineering & Technology, 2004Co-Authors: Bingtao ZhaoAbstract:Based on investigation of the flow pattern in Cyclone Separators, a new theoretical model was developed for the prediction of pressure drop across Cyclone Separators. This model includes the effect of the geometrical dimensions and flow parameters, and assumes that the total pressure drop consists of four main partial pressure drops due to gas expansion at the separator entrance, wall friction within the separator, swirling motion of the gas, and gas flow through the outlet pipe. The availability of the method is verified by the comparison of calculated values with experimental data and with other models for different dimensions of Cyclones.
Irfan Karagoz - One of the best experts on this subject based on the ideXlab platform.
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performance analysis of axial and reverse flow Cyclone Separators
Chemical Engineering and Processing, 2019Co-Authors: Ali Sakin, Irfan Karagoz, Atakan AvciAbstract:Abstract Performance characteristics of a novel Cyclone with tangential inlet were presented in axial and reverse flow operation modes. 3-D and unsteady governing equations were used for the numerical solution of the two-phase turbulent flow in the Cyclone separator. The Eulerian approach was used to solve the flow field, and the Reynolds Stress Model (RSM) with the scalable wall function was employed for the numerical study. The Lagrangian approach with the Discrete Phase Model was used to calculate the discrete phase by releasing particles from the inlet surface. CFD calculations were run for different geometric configurations to analyze the performance of the Cyclones regarding pressure drop, cut-off diameter, and fractional efficiency. Axial and tangential velocity profiles are presented at the defined sections. The computational results of pressure drop, velocity field, and separation efficiency were also compared for the axial and reverse flow Cyclones at the same flow rate. The results show that pressure drop and collection efficiency in reverse flow mode are higher than that of the axial flow operation. However, axial flow Cyclones seem to be more efficient for small particles comparing to reverse flow Cyclones.
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effects of surface roughness on the performance of tangential inlet Cyclone Separators
Aerosol Science and Technology, 2011Co-Authors: Fuat Kaya, Irfan Karagoz, Atakan AvciAbstract:This study is carried out to investigate the effects of surface roughness on the flow field and Cyclone performance. The flow inside the Cyclone separator is modeled as a three-dimensional turbulent continuous gas flow with solid particles as a discrete phase. The continuous gas flow is predicted by solving the governing equations by using the Reynolds Stress turbulence model, and the modeling of the particle motions is based on a Lagrangian approach. The results of the numerical simulations are compared with experimental data as well as with the results of mathematical models. Analysis of computed results shows that increase of relative roughness due to corrosion, wear, or accumulation of particles on the inner walls considerably influences the tangential velocity, Cyclone separation efficiency, and Cyclone pressure drop especially for high inlet velocities. Decreases in Cyclone collection efficiency and pressure drop with the increase in surface roughness are found to be more pronounced for high values ...
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usability of Cyclone Separators as air filters in vehicles
International Journal of Vehicle Design, 2010Co-Authors: Irfan Karagoz, Fuat Kaya, Atakan AvciAbstract:This study deals with the use of Cyclone Separators as air filters in light or heavy duty vehicles. Cyclone Separators were compared with the conventional air filters, which provide low particle collection efficiency with high pressure drop, and these characteristics are made worse by contamination. By taking into account the related studies in the literature, tangential inlet Cyclones were considered in this comparison. The pressure drop and particle collection efficiency in the proposed tangential inlet Cyclone were computed by using the mathematical models given in the literature. Comparison of the computed results of the Cyclone with the conventional air filters demonstrated that the tangential inlet Cyclones are advantageous because of low pressure drop and high particle collection efficiency and can be used as main or pre-filters in vehicles.
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modelling of the pressure drop in tangential inlet Cyclone Separators
Aerosol Science and Technology, 2005Co-Authors: Irfan Karagoz, Atakan AvciAbstract:This article introduces a new mathematical model that predicts the pressure drop in a tangential inlet Cyclone. The model calculates the pressure drop from the frictional losses in the Cyclone body, using a wall friction coefficient based on the surface roughness and Reynolds number. The entrance and exit losses are also included in the model by defining new geometrical parameters. The pressure drop coefficient is obtained as a function of Cyclone dimensions and operating conditions. The model is validated by studying 12 different Cyclones presented in the literature. Comparison of the model results with predictions and measurements published in the literature show that the new model predicts the experimental results quite well for a wide range of operating conditions covering a flow rate of 0.3–220 l/s and a temperature range of 293–1200°K, in different Cyclones. The pressure drop coefficient is also examined in view of the outlet pipe diameter, friction coefficient, surface roughness, and Reynolds number.
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effects of flow and geometrical parameters on the collection efficiency in Cyclone Separators
Journal of Aerosol Science, 2003Co-Authors: Atakan Avci, Irfan KaragozAbstract:A mathematical model has been developed for calculation of cut-off size and fractional efficiencies in Cyclone Separators, by taking into account the effects of flow, particle and geometrical parameters, and acceleration assuming that the mixture of fluid and particles is homogenous, and acceleration diminishes depending on the friction and geometry. Collection efficiency curves and cut-off size values predicted by the proposed model showed a good agreement with experiments over a wide range of inlet velocities for different types of Cyclones. Comparison of the obtained results with semi empirical models available in literature also indicated that the present model may be used successfully for determination of the performance of a tangential inlet Cyclone. Analyses of the effects of various parameters reveals that, in addition to flow and geometrical parameters, surface friction, vortex length and flow regimes play an important role on Cyclone performance especially in small Cyclones.
Hamed Safikhani - One of the best experts on this subject based on the ideXlab platform.
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numerical study of flow field in new design Cyclone Separators with one two and three tangential inlets
Advanced Powder Technology, 2017Co-Authors: Hamed Safikhani, Javid Zamani, Mohammadreza MusaAbstract:Abstract Numerical study of the fluid flow and particle dynamics is presented by numerical techniques to characterize the performance of new design Cyclone Separators with one, two and three tangential inlets. The design of this Cyclone is based on the idea of improving Cyclone performance by increasing the vortex length. This Cyclone differs from a conventional Cyclone with the separation space. Instead of conical part, the separation space of this Cyclone consists of an outer cylinder and a vortex limiter. The Reynolds averaged Navier–Stokes equations with Reynolds stress turbulence model (RSM) are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the computational domain. The Eulerian-Lagrangian computational procedure is used to predict particles tracking in the Cyclones. The velocity fluctuations are simulated using the Discrete Random Walk (DRW). In the results the effects of number of inlets on the different important parameters such as pressure drop, collection efficiency, axial velocity and turbulence are investigated and deeply discussed. Contours of velocity, pressure and turbulent kinetic energy within these Cyclones with different number of inlets are shown. The results show that the Cyclone with three inlets has more collection efficiency, less pressure drop and less turbulence distribution with respect to Cyclones with one and two inlets which is good in Cyclones performance. Generally it is recommended to use the new Cyclone designs with higher number of inlets.
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modeling and multi objective pareto optimization of new Cyclone Separators using cfd anns and nsga ii algorithm
Advanced Powder Technology, 2016Co-Authors: Hamed SafikhaniAbstract:Abstract In this article, Multi-Objective Optimization (MOO) of new Cyclone Separators namely Karagoz Cyclones is performed using Computational Fluid Dynamics (CFD), Artificial Neural Networks (ANN) and Non-dominated Sorting Genetic Algorithms (NSGA II). The design of this Cyclone is based on the idea of improving Cyclone performance by increasing the vortex length. This Cyclone differs from a conventional Cyclone with the separation space. Instead of conical part, the separation space of this Cyclone consists of an outer cylinder and a vortex limiter. For multi-objective optimization process at first, the flow field is solved numerically in various Karagoz Cyclones using CFD techniques and collection efficiency ( η ) and pressure drop ( Δ P ) in Cyclones are calculated. In this step the Reynolds averaged Navier–Stokes equations with Reynolds stress turbulence model (RSM) are solved. The Eulerian-Lagrangian computational procedure is used to predict particles tracking in the Cyclones and the velocity fluctuations are simulated using the Discrete Random Walk (DRW). In the next step, numerical data of the previous step will be applied for modeling η and Δ P using Grouped Method of Data Handling (GMDH) type ANNs. Finally, the modeling achieved by GMDH will be used for Pareto based multi-objective optimization of geometrical parameters in new Cyclones using NSGA II algorithm. It is shown that the achieved Pareto solution includes important design information on new Cyclones.
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numerical study of flow field in new Cyclone Separators
Advanced Powder Technology, 2016Co-Authors: Hamed Safikhani, Pegah MehrabianAbstract:Abstract Numerical study of the fluid flow and particle dynamics is presented by numerical techniques to characterize the performance of new Cyclone Separators. The design of this Cyclone is based on the idea of improving Cyclone performance by increasing the vortex length. This Cyclone differs from a conventional Cyclone with the separation space. Instead of conical part, the separation space of this Cyclone consists of an outer cylinder and a vortex limiter. The Reynolds averaged Navier–Stokes equations with Reynolds stress turbulence model (RSM) are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the computational domain. The Eulerian–Lagrangian computational procedure is used to predict particles tracking in the Cyclones. The velocity fluctuations are simulated using the Discrete Random Walk (DRW). In the results the dependency of collection efficiency and pressure drop on different geometrical parameters is investigated. Contours of velocity, pressure and turbulent kinetic energy within these Cyclones are shown. Tangential velocity profiles and velocity vectors in different sections are investigated.
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modeling and multi objective optimization of Cyclone Separators using cfd and genetic algorithms
Computers & Chemical Engineering, 2011Co-Authors: Hamed Safikhani, Amir Hajiloo, M A RanjbarAbstract:Abstract In the present study, multi-objective optimization of Cyclone Separators is performed at three steps. At the first step, pressure drop (Δ p ) and the cut-point ( D 50 ) in a set of Cyclone Separators are numerically investigated using CFD techniques. Two meta-models based on the evolved group method of data handling (GMDH) type neural networks are obtained, at the second step, for modeling of Δ p and D 50 with respect to geometrical design variables. Finally, using obtained polynomial neural networks, multi-objective genetic algorithms are used for Pareto based optimization of Cyclone Separators considering two conflicting objectives, Δ p and D 50 . It is shown that some interesting and important relationships as useful optimal design principles involved in the performance of Cyclones can be discovered by Pareto based multi-objective optimization of the obtained polynomial meta-models.
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effects of using ribs on flow pattern and performance of Cyclone Separators
Engineering Applications of Computational Fluid Mechanics, 2011Co-Authors: S Noode M Farahani, Hamed Safikhani, V Tahmasbi, Abbas AbbassiAbstract:Abstract:In this paper, the effects of using ribs on the flow pattern and performance of Cyclone Separators are investigated using CFD techniques. The Reynolds averaged Navier-Stokes equations with Reynolds Stress Turbulence Model (RSTM) are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the computational domain. The Eulerian-Lagrangian computational procedure is used to predict particles tracks in Cyclones with different rib pitch to Cyclone diameter (P/D) ratios. The velocity fluctuations are simulated using Discrete Random Walk (DRW). The results show that using ribs in Cyclones leads to higher collection efficiency but higher pressure drop and the Cyclone with P/D equal to 1 has the maximum collection efficiency among the ribbed Cyclones and the Cyclone without ribs has the least pressure drop.
Diego De Moro Martins - One of the best experts on this subject based on the ideXlab platform.
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simulation of the performance of small Cyclone Separators through the use of post Cyclones poc and annular overflow ducts
Separation and Purification Technology, 2015Co-Authors: Francisco Jose De Souza, Ricardo De Vasconcelos Salvo, Diego De Moro MartinsAbstract:Abstract The cut-off diameter of a Cyclone separator is directly related to its design, which in turn is based on the expected operational conditions. Consequently, if operational conditions change or if the priori conditions remain unchanged but the cut-off diameter must be decreased, the separator will probably display unsatisfactory performance, and a new design may be necessary. This work focus on two different approaches for increasing collection efficiency in small Cyclone Separators without any modifications in the Cyclone body, namely the use of a PoC – Post Cyclone and the use of an annular tube on the overflow duct. Both approaches take advantage of the remaining swirl in the overflow duct. The results are obtained through CFD computations based on LES of the fluid flow inside the separator and a Lagrangian description of the dispersed phase. Results show that the PoC may be successfully applied to small size Cyclone Separators, increasing the collection efficiency even for particle diameters smaller than two micrometers. On the other hand, the annular outlet duct did not perform as expected and for the tested conditions, the increase in separation was directly related to the bleed flow rate.
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effects of the gas outlet duct length and shape on the performance of Cyclone Separators
Separation and Purification Technology, 2015Co-Authors: Francisco Jose De Souza, Ricardo De Vasconcelos Salvo, Diego De Moro MartinsAbstract:Abstract In most published studies regarding the numerical simulation of Cyclone Separators, the gas outlet duct is usually treated as a short straight duct, differing considerably from the experimental apparatus, in which a relatively long duct followed by a curve, or vice versa, is generally used. This work focuses on the influence of length and shape of the outlet duct on the grade efficiency and pressure drop inside a small Cyclone separator. The results are obtained through Large Eddy Simulation of the fluid flow inside the separator, coupled with a concomitant Lagrangian description-based on Newton’s second law-of the dispersed phase. More than thirty different outlet duct configurations, including different lengths, curves, curves positions and curvature radii were simulated. The results show that the Cyclone gas outlet duct may affect the Cyclone performance: the pressure drop initially decreases with duct length until a minimum is reached, and from this point on it monotonically increases with duct length. As for the cut off diameter, the relation showed itself much more complex.
