Performance Characteristics of Electrocyclone With Various Inlet Shapes

2005 ◽  
Author(s):  
J.-I. Hong ◽  
Youn J. Kim ◽  
J.-G. Han ◽  
J.-K. Oh
Keyword(s):  
Particle Size ◽  
Pressure Drop ◽  
Collection Efficiency ◽  
Performance Characteristics ◽  
The Other ◽  
Pressure Drops ◽  
Median Diameter ◽  
Vortex Finder ◽  
Velocity Changes ◽  
Mass Median Diameter

In this study, the performance characteristics of electro-cyclone with different inlet shapes, such as helical, tangential and involute, were experimentally investigated. The range of particle size has 0.3 to 6 μm and the inlet velocities are 10, 15, 20, and 25 m/s. Particles used in this experiment are JIS Class 11 test powder which have the density of 1.9~2.1 g/cm3 and the mass median diameter of 2.3 μm. An electrocyclone has discharge wire which was inserted in the middle of vortex-finder. The length, diameter and material of discharge wire have 20 mm, 0.6 mm and SUS304, respectively. The discharge wire was applied with a voltage of 10 kV. The collection efficiency is calculated by the particle size distribution of the upstream and downstream using a laser optical particle counter. Pressure drops were measured between two pressure taps which were located at the inlet and outlet ducts of electrocyclone using a micromanometer. For the case of the involute type, due to a minimum turbulence, the retention time of particles becomes long in electrocyclone and particles have more chances to be charged. However, the experimental results show that a helical shape has a better collection effect than the other shapes. And the pressure drop of the involute shape for a given inlet velocity is smaller than the other shapes. The collection efficiency and the pressure drop with various inlet shapes and velocity changes in electrocyclone are graphically depicted.

scholarly journals Grid convergence study of a cyclone separator using different mesh structures

2017 ◽  
Vol 23 (3) ◽  
pp. 311-320 ◽  
Author(s):  
R.A.F. Oliveira ◽  
G.H. Justi ◽  
G.C. Lopes
Keyword(s):  
Pressure Drop ◽  
Collection Efficiency ◽  
Fluid Dynamic ◽  
Two Phase ◽  
Mesh Structure ◽  
Pressure Drops ◽  
Regular Elements ◽  
Grid Convergence ◽  
Grid Convergence Index ◽  
Mesh Structures

In a cyclone design, pressure drop and collection efficiency are two important performance parameters to estimate its implementation viability. The optimum design provides higher efficiencies and lower pressure drops. In this paper, a grid independence study was performed to determine the most appropriate mesh to simulate the two-phase flow in a Stairmand cyclone. Computational fluid dynamic (CFD) tools were used to simulate the flow in an Eulerian-Lagrangian approach. Two different mesh structure, one with wall-refinement and the other with regular elements, and several mesh sizes were tested. The grid convergence index (GCI) method was applied to evaluate the result independence. The CFD model results were compared with empirical correlations from bibliography, showing good agreement. The wall-refined mesh with 287 thousand elements obtained errors of 9.8% for collection efficiency and 14.2% for pressure drop, while the same mesh, with regular elements, obtained errors of 8.7% for collection efficiency and 0.01% for pressure drop.

scholarly journals Case Studies of Air Filtration at Microscales: Micro- and Nanofiber Media

2008 ◽  
Vol 3 (2) ◽  
pp. 155892500800300 ◽  
Author(s):  
Benoît Mazé ◽  
Hooman V. Tafreshi ◽  
Behnam Pourdeyhimi
Keyword(s):  
Pressure Drop ◽  
Fiber Diameter ◽  
Collection Efficiency ◽  
Particle Diameter ◽  
Molecular Flow ◽  
Air Filtration ◽  
Gas Temperature ◽  
Pressure Drops ◽  
Continuum Flow ◽  
The Media

In this work, 3–D fibrous geometries are developed to resemble the microstructure of spun-bonded and electrospun filters media and used here to simulate their filtration efficiency and pressure drop. For the sake of simplicity, a continuum flow theory was considered to prevail for the case of spun-bonded media (microfiber media) whereas our electrospun media (nanofiber media) were assumed to be in a free molecular flow regime. Our simulations results are in good general agreement with the experimental data. Especially, in predicting media's pressure drop, our results show better predictions when compared to some of the existing models. We also quantitatively demonstrated that by decreasing the fiber diameter, the minimum collection efficiency of the media having identical pressure drops increases. This effect is accompanied by a decrease in the particle diameter associated with these minimum efficiencies – the most penetrating particle diameter. Studying the influence of the gas temperature, we showed that filter's efficiency increases as the gas temperature increases. Conversely, the filter's pressure drop decreases by increasing the gas temperature.

scholarly journals Effects of Pressure Drops on the Performance Characteristics of Air Standard Otto Cycle

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Mahmoud Huleihil
Keyword(s):  
Pressure Drop ◽  
Constant Pressure ◽  
Performance Characteristics ◽  
Maximum Efficiency ◽  
Maximum Pressure ◽  
Otto Cycle ◽  
Pressure Drops ◽  
Internal Irreversibility ◽  
Expansion Model ◽  
Engine Size

The effects of pressure drops on the performance characteristics of the air standard Otto cycle are reported. The pressure drops are assumed as constant values independent of the engine size. It has been shown that the pressure drops to about 60% of the maximum pressure in the ideal cycle (Curto-Risso et al., 2008). Three different models are studied: constant pressure model, reversible adiabatic expansion model and polytropic expansion model. The findings of this study show that, at this level of pressure drop, the maximum efficiency of the Otto cycle is reduced by 15% approximately based on the constant pressure model. The combined effect of pressure drop with other modes of irreversibility, for example, internal irreversibility and heat leaks, could reduce the maximum efficiency into very low values (approximately 30%). The reversible adiabatic model predicts reduction of 13% in efficiency at 40% pressure drop levels but at the price of zero power production. On the other hand, the polytropic expansion model predicts 40% reduction in efficiency for the same level of pressure drop (40%). All three models show that the power output is very sensitive to pressure drop.

scholarly journals Effects of convergent–divergent vortex finders on the performance of cyclone separators using computational fluid dynamics simulations

SIMULATION ◽  
2019 ◽  
Vol 96 (1) ◽  
pp. 31-42
Author(s):  
Vikash Kumar ◽  
Kailash Jha
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Pressure Drop ◽  
Collection Efficiency ◽  
Flow Simulation ◽  
Reynolds Stress Model ◽  
Continuity Equations ◽  
Vortex Finder ◽  
Uniform Diameter

This study investigates the effect of convergent–divergent vortex finders on the performance of cyclone separators, which is measured in terms of pressure drop and collection efficiency. Six cyclone models (two with uniform diameter and four with convergent–divergent vortex finders) were numerically simulated. The numerical simulations have been carried out using the commercial computational fluid dynamics code (CFD) Fluent v15. The simulation procedure has been validated using experimental data from the published literature where a good agreement between the numerical results and the experimental data is seen. A grid independence test has been carried out by using two levels of grids for correctness of our simulation. The Reynolds averaged Navier–Stokes (RANS) and continuity equations have been solved for the flow simulation. The Reynolds stress model is used for modeling the stress tensor and closing the RANS equations. The results show that a convergent–divergent vortex finder is capable of producing better performance (pressure drop and collection efficiency) than the uniform diameter cyclones. Only one performance parameter can be improved in uniform diameter cyclones. In comparison to the standard uniform vortex finder cyclones, the convergent–divergent vortex finder improves the pressure drop by 6% and also reduces the cut-size to 1.4 from 1.6 µm. It is further seen that decreasing the throat area or increasing only the lower diameter of the vortex finder causes the performance to degrade. This study proves that convergent–divergent instead of uniform diameter vortex finders can be used in gas cyclones for obtaining a better performance with the same geometry.

Experimental Investigation on Atomization Properties of Coal-Water Paste Fired Into Pressurized Fluidized Bed Combustor

2003 ◽  
Author(s):  
Ping Lu ◽  
Mingyao Zhang
Keyword(s):  
Particle Size ◽  
Mass Ratio ◽  
Piv Measurement ◽  
Median Diameter ◽  
Processing Software ◽  
Image Processing Software ◽  
Fluidized Bed Combustor ◽  
Mass Median ◽  
Mass Median Diameter

According to the properties of coal-water paste (CWP), a series of experimental devices were constructed to study the atomizing characteristics of the CWP nozzle deeply. The particle size and its distribution of several types of atomizing nozzle of CWP in the spray are measured by PIV measurement and newly developed image processing software. The influences of every factor on the atomizing properties are analyzed. The atomizing experimental results show that atomizing quality of CWP was found to correlate with the characteristics of CWP, air to CWP mass ratio, atomizing air motion, coal particle size distribution and the structure of atomizer etc. mass median diameter (MMD) of atomizing particle decrease with the increase of gas to CWP mass ratio, and the proper type of nozzle and proper parameters for engineering are suggested.

Comparative Analysis of Various CFBC Cyclone Separator REPDS Profiles

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
N. Prasanna ◽  
R.S. Prakash ◽  
M. Vijayakumar
Keyword(s):  
Pressure Drop ◽  
Circulating Fluidized Bed ◽  
Collection Efficiency ◽  
Cyclone Separator ◽  
Fluidized Bed Combustion ◽  
Reduced Pressure ◽  
Denudation Rate ◽  
Computational Fluid Dynamics Analysis ◽  
Vortex Finder ◽  
Circulating Fluidized Bed Combustion

In the last decade research on CFBC (Circulating Fluidized Bed Combustion Boiler) has been increased but research on cyclone separator has not been paid well attention. All the existing designs of cyclone separator were mainly concentrating on a single parameter that is collection efficiency. But this work mainly concentrates on other parameters like pressure drop and denudation rate. Previous works related to cyclone separator having REPDS (Reduced Pressure Drop Stick) suggest that 50% REPDS in the vortex finder gives the optimum results for all the existing cyclone models. Existing REPDS profile is only circular; we attempted to change the REPDS profile to polygon shapes like square, hexagonal. All the cyclone separators with different REPDS profile have been designed for flow rate of 500m3/hr with operating velocity of 15m/s. CFD (Computational Fluid Dynamics) analysis has been done with operating velocity ranging from 15m/s to 30m/s, using K-€ turbulence model. The results obtained in CFD analysis reveal that there is no much variation in pressure drop, but there is a drastic change in the denudation rate while operating CFBC cyclone separator twice the designed velocity. Thus REPDS can be included in vortex finder of cyclone separator with any polygon profiles as mentioned above.

scholarly journals Optimized graded screen array configuration for particle size distribution of radon progeny in standard chamber

2019 ◽  
Vol 34 (3) ◽  
pp. 272-277
Author(s):  
Rui Chen ◽  
Shu-Min Zhou
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Collection Efficiency ◽  
Theoretical Calculations ◽  
Radon Progeny ◽  
Array Configuration ◽  
Comparison Research ◽  
Median Diameter ◽  
Array Measurement

Particle size distribution of radon progeny is one of the most important parameters and it needs to be measured accurately. Graded screen array measurement is the most frequently used method for analyzing the characteristics of radon progeny but it needs optimization due to its complex configuration. In this paper, collection efficiency of a single screen and the number of screen array were applied for optimization and simplification of the graded screen array configuration by a series of experimental measurements, theoretical calculations, and standard comparison research methods. When optimized in this way, an experiment was designed for radon progeny particle size distribution in a customized radon chamber. The experiment results indicated that the activity median diameter in unattached mode was 0.81 nm and 287.32 nm in attached mode, which were similar to the results obtained by other researchers. The results prove that the method can satisfy the requirements of graded screen array measurement.

scholarly journals Configuration of a newly optimized multi-cyclones unit as a fine particulate emission separator in air pollution control

2020 ◽  
Vol 16 (1) ◽  
pp. 90-95
Author(s):  
Norelyza Hussein ◽  
Mohd Rashid Mohd Yusof ◽  
Nur Hasyimah Hashim ◽  
Eeydzah Aminudin ◽  
Che Hafizah Che Hassan
Keyword(s):  
Pressure Drop ◽  
Collection Efficiency ◽  
Small Diameter ◽  
Theoretical Background ◽  
Air Pollution Control ◽  
Particulate Emission ◽  
Final Design ◽  
Vortex Finder ◽  
Actual Size ◽  
Selection Of

Multi-cyclones separator, which consists of many miniature cyclones, works in the same principle as single cyclone in separation of particulate matter from flue gas. However, multi-cyclone is able to attain higher collection efficiency and concurrently avoid rapid increasing of pressure drop due to the usage of small diameter cyclone. The studies on multi-cyclones are very limited and lacking especially on its design configurations due to its confidentiality and commercial reason. Thus, a configuration of a newly optimized multi-cyclone unit named as MR-deDuster is discussed and assessed in this study. Six dimensions considered in the study include diameter of cyclone (D), diameter of vortex finder (De), length of cyclone body (Lb), length of cyclone cone (Lc), length of vortex finder (S), and diameter of dust outlet (Dd). The theoretical background of the unit was developed based on the modifications of established design equations available in literatures. The selection of the new dimension and the actual size of the unit were based on two main criteria (the performance of the unit based on its cut-diameter and the ratio of axial dimensions). The predicted cut-diameter and pressure drop of the selected dimension was 1.7 µm and 86 mm of water, respectively. Meanwhile, the optimum axial ratios of the final design were Lb/D = 1.6, S/D = 1, and Lb-S/D = 0.7, with respect to the diameter of the cyclone.

scholarly journals Computational Study of Operating Parameters on Performance of Compound Hydrocyclone

2021 ◽  
Vol 9 (VII) ◽  
pp. 2517-2524
Author(s):  
R. Giridhar
Keyword(s):  
Pressure Drop ◽  
Separation Efficiency ◽  
Collection Efficiency ◽  
Computational Study ◽  
Saddle Points ◽  
Turbulence Models ◽  
Pressure Drops ◽  
Eddy Simulation ◽  
Discrete Phase ◽  
Rsm Model

The dynamics of hydro cyclones is complex, because it is a multiphase flow problem that involves interaction between a discrete phase and multiple continuum phases. The performance of hydro cyclones is evaluated by using Computational Fluid Dynamics (CFD), and it is characterized by the pressure drop, split water ratio, and particle collection efficiency. In this paper, a computational model to improve and evaluate hydro cyclone performance is proposed. Computational turbulence models (renormalization group (RNG) k-ε, Reynolds’s stress model (RSM), and large-eddy simulation (LES)) are implemented, and the accuracy of each for predicting the hydro cyclone behavior is assessed. Four hydro cyclone configurations were analyzed using the RSM model. By analyzing the streamlines resulting from those simulations, it was found that the formation of some vortices and saddle points affect the separation efficiency. Furthermore, the effects of inlet width, cone length, and vortex finder diameter were found to be significant. The cut-size diameter was decreased compared to the Hsieh experimental hydro cyclone. An increase in the pressure drops leads to high values of cut-size and classification sharpness. If the pressure drop increases to twice its original value, the cut-size and the sharpness of classification are reduced to their initial values, respectively.

scholarly journals Numerical prediction of short-cut flows in gas-solid reverse flow cyclone separators

2017 ◽  
Vol 23 (4) ◽  
pp. 483-493 ◽  
Author(s):  
Ali Sakin ◽  
Irfan Karagoz
Keyword(s):  
Collection Efficiency ◽  
Reverse Flow ◽  
Reynolds Stress Model ◽  
Solid Particles ◽  
Phase Method ◽  
Geometrical Parameters ◽  
Pressure Drops ◽  
Discrete Phase Method ◽  
Discrete Phase ◽  
Vortex Finder

The effect of operational and geometrical parameters on the short-cut flow in cyclone separators has been investigated computationally using the Reynolds stress model (RSM). The motion of solid particles in the flow field was simulated using the Eulerian-Lagrangian approach with one way discrete phase method (DPM). Eleven cyclones with different cone tip diameters, vortex finder lengths and diameters were studied and the simulation results were analyzed in terms of velocity fields, pressure drops, cut-off diameters and short-cut flows. The numerical simulation was verified with the published experimental results. The results obtained demonstrate that all three parameters, particularly, vortex finder diameter, have significant effects on the cut-off diameter (collection efficiency), the short-cut flow and the pressure drop.

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