CFD STUDY OF CYCLONE PERFORMANCE: EFFECT OF INLET SECTION ANGLE AND PARTICLE SIZE DISTRIBUTION

2016 ◽  
Vol 78 (6-4) ◽  
Author(s):  
Ratchanon Piemjaiswang ◽  
Kongpob Ratanathammapan ◽  
Prapan Kunchonthara ◽  
Pornpote Piumsomboon ◽  
Benjapon Chalermsinsuwan
Keyword(s):  
Pressure Drop ◽  
Gas Flow ◽  
Collection Efficiency ◽  
Solid Particles ◽  
Inlet Section ◽  
Two Phase ◽  
Performance Effect ◽  
Computational Fluid Dynamics Cfd ◽  
Inlet Angle ◽  
Numerical Simulation Technique

A numerical simulation technique was employed to model the two phase flow in cyclones using computational fluid dynamics (CFD). Three different inlet angles of cyclone, including 45, 0 and -45 degrees were compared to describe the efficiency of the conventional cyclone with the modified inlet angle ones. The results showed that the interaction between solid particles in dilute system could be neglected. The pressure drop was decreased when the inlet angle of the cyclone increased. The cyclone with 45 degrees inlet angle tended to have the lowest pressure drop. The collection efficiency was improved with 45 degrees inlet angle due to high swirling motion of gas flow. 

Effects of Inlet Geometry on the Pressure Drop and Collection Efficiency of Tangential Inlet Cyclones

2010 ◽  
Author(s):  
Mehmet Teke ◽  
I˙rfan Karago¨z
Keyword(s):  
Pressure Drop ◽  
Gas Flow ◽  
Stokes Equations ◽  
Collection Efficiency ◽  
Flow Behavior ◽  
Dynamics Simulation ◽  
Second Phase ◽  
Inlet Section ◽  
Inlet Geometry ◽  
Tangential Inlet

This work presents a computational fluid dynamics simulation to investigate the effects of inlet geometry on the pressure drop and particle collection efficiency of a tangential inlet cyclone. Three-dimensional, steady governing equations for the incompressible, turbulent flow inside a tangential inlet cyclone are solved numerically under certain boundary conditions. The continuous gas flow is predicted by solving Navier-Stokes equations using the differential RSM turbulence model. The second phase is modeled based on a Lagrangian approach. The commercial CFD code Fluent was used for numerical analysis. Computational results compared experimental data available in the literature for validation. Various cyclones, each has different geometrical ratio of inlet section, studied in this paper. Detail analyses of the effects of inlet geometry on the flow behavior, pressure drop and collection efficiency were given.

A CFD Study of Gas-Solid Flow in Cyclones With a Tangential Single Inlet and a Direct Asymmetrical Spiral Inlet

2009 ◽  
Author(s):  
Bin Xiong ◽  
R. S. Amano ◽  
Xiaofeng Lu ◽  
Yingfeng Ji
Keyword(s):  
Pressure Drop ◽  
Velocity Distribution ◽  
Gas Flow ◽  
Collection Efficiency ◽  
Tangential Velocity ◽  
Reynolds Stress Model ◽  
Lagrangian Model ◽  
Solid Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Paths

This work presents a computational fluid dynamics (CFD) calculation of gas-solid flow in cyclones with a conventional tangential single inlet (CTSI) and a direct symmetrical spiral inlet (DSSI) which was developed by Zhao et al [1]. The Reynolds stress model (RSM) has been employed to predict the gas flow field and particle paths are calculated with the stochastic Lagrangian model. The calculated grade collection efficiency and pressure drop have reasonable agreement with the experimental data. All results indicate that the DSSI has effect on significantly increasing collection efficiency with insignificantly increasing pressure drop. Compared with the CTSI cyclone, the DSSI cyclone has higher collection efficiency due to larger tangential velocity distribution, less short re-circuiting flow and shorter distance for particles to move to the wall. But the larger tangential velocity distribution lead to a little higher pressure drop of the cyclone with DSSI.

Two-Phase Flows in Mini-/Micro-Gas Flow Channels of PEM Fuel Cells

2013 ◽  
Author(s):  
Sung Chan Cho ◽  
Yun Wang
Keyword(s):  
Pressure Drop ◽  
Gas Flow ◽  
Fluid Model ◽  
Pem Fuel Cells ◽  
Two Phase ◽  
Micro Gas Flow ◽  
Two Fluid Model ◽  
The Impact ◽  
Two Fluid ◽  
Phase Pressure

In this paper, two-phase flow dynamics in a micro channel with various wall conditions are both experimentally and theoretically investigated. Annulus, wavy and slug flow patterns are observed and location of liquid phase on different wall condition is visualized. The impact of flow structure on two-phase pressure drop is explained. Two-phase pressure drop is compared to a two-fluid model with relative permeability correlation. Optimization of correlation is conducted for each experimental case and theoretical solution for the flows in a circular channel is developed for annulus flow pattern showing a good match with experimental data in homogeneous channel case.

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.

Analysis of Pressure Drop and Water Flooding of Two-Phase Flow Along Channels for a PEM Fuel Cell System

2009 ◽  
Author(s):  
Jinglin He ◽  
Song-Yul Choe ◽  
Chang-Ouk Hong
Keyword(s):  
Fuel Cell ◽  
Pressure Drop ◽  
Relative Humidity ◽  
Liquid Water ◽  
Water Distribution ◽  
Gas Flow ◽  
Pem Fuel Cell ◽  
Cell System ◽  
Water Flooding ◽  
Two Phase

The flow in gas flow channels of an operating polymer electrolyte membrane (PEM) fuel cell has a two-phase characteristic that includes air, water vapor and liquid water and significantly affects the water flooding, pressure distribution along the channels, and subsequently the performance of the cell and system. Presence of liquid water in channels prevents transport of the reactants to the catalysts and increases the pressure difference between the inlet and outlet of channels, which leads to high parasitic power of pumps used in air and fuel supply systems. We propose a model that enables prediction of pressure drop and liquid water distribution along channels and analysis of water flooding in an operating fuel cell. The model was developed based on a gas-liquid two-phase separated flow that considers the variations of gas pressure, mass flow rate, relative humidity, viscosity, void fraction, and density along the channels on both sides. Effects of operating parameters that include stoichoimetric ratio, relative humidity, and inlet pressure on the pressure drop and water flooding along the channels were analyzed.

Numerical Simulation of Bubble Formation in Co-Flowing Mercury

2008 ◽  
Author(s):  
Ashraf Ibrahim ◽  
Mark Wendel ◽  
David Felde ◽  
Bernard Riemer
Keyword(s):  
Acoustic Waves ◽  
Bubble Growth ◽  
Gas Flow ◽  
Bubble Formation ◽  
Science Center ◽  
Proton Radiography ◽  
Two Phase ◽  
Vof Model ◽  
Computational Fluid Dynamics Cfd ◽  
Bubble Sizes

In this work, we present computational fluid dynamics (CFD) simulations of helium bubble formation and detachment at a submerged needle in stagnant and co-flowing mercury. Since mercury is opaque, visualization of internal gas bubbles was done with proton radiography (pRad) at the Los Alamos Neutron Science Center (LANSCE2). The acoustic waves emitted at the time of detachment and during subsequent oscillations of the bubble were recorded with a microphone. The Volume of Fluid (VOF) model was used to simulate the unsteady two-phase flow of gas injection in mercury. The VOF model is validated by comparing detailed bubble sizes and shapes at various stages of the bubble growth and detachment, with the experimental measurements at 1.66 mg/min helium gas flow rate and different mercury velocities. The experimental and computational results show a two-stage bubble formation in stagnant mercury. The first stage involves growing bubble around the needle, and the second follows as the buoyancy overcomes wall adhesion. The comparison of predicted and measured bubble sizes and shapes at various stages of the bubble growth and detachment is in good agreement.

EQUILIBRIUM VELOCITY DISTRIBUTION FUNCTIONS FOR A KINETIC MODEL OF TWO-PHASE FLOWS

1995 ◽  
Vol 05 (02) ◽  
pp. 191-211 ◽  
Author(s):  
LIONEL SAINSAULIEU
Keyword(s):  
Velocity Distribution ◽  
Gas Flow ◽  
Stokes Equations ◽  
Volume Fraction ◽  
Velocity Distribution Function ◽  
Distribution Functions ◽  
Solid Particles ◽  
Navier Stokes ◽  
Two Phase ◽  
Entropy Balance

We consider a cloud of solid particles in a gas flow. The cloud is described by a probability density function which satisfies a kinetic equation. The gas flow is modeled by Navier-Stokes equations. The two phases exchange momentum and energy. We obtain the entropy balance of the gas flow and deduce some bounds for the volume fraction of the gas phase. Writing the entropy balance for the dispersed phase enables one to determine the particles equilibrium velocity distribution function when the gas flow is known.

scholarly journals Performance of a cyclone scrubber on removal of fine particulate matter

2020 ◽  
Vol 26 (1) ◽  
pp. 31-40
Author(s):  
Ana Achiles ◽  
Vádila Guerra
Keyword(s):  
Pressure Drop ◽  
Sugar Cane ◽  
Gas Flow ◽  
High Efficiency ◽  
Fine Particles ◽  
Collection Efficiency ◽  
Sugar Cane Bagasse ◽  
Flow Ratio ◽  
Liquid Injection ◽  
Gas Flow Ratio

Cyclones are not classified as effective devices for removing fine particles, while high efficiency wet scrubbers usually have high operational costs. In order to achieve better performance, the aim of this study is to evaluate, for the first time, a cyclone scrubber design based on the dimensions of a Stairmand cyclone separator with the inclusion of liquid injection nozzles located in different positions to improve the separation of fine particles. Given the lack of studies considering the effect of liquid injection and other operational conditions in the removal performance of a cyclone scrubber with Stairmand dimensions, the present paper provides a complete evaluation of these effects for the separation of sugar cane bagasse ash from air. The parameters investigated were inlet gas velocity, liquid injection position, liquid-to-gas flow ratio and droplet size distribution. The cyclone scrubber performance was evaluated considering collection efficiency and pressure drop. Overall efficiency of almost 99% and low-pressure drop was achieved by employing a liquid-to-gas flow ratio of 0.43 L/m? for the collection of ash from the combustion of sugar cane bagasse. Grade efficiencies revealed that injecting droplets into cyclones significantly improved the removal of fine particles with an aerodynamic diameter less than 2.5 ?m.

CFD Simulation of Solid Suspension in a Stirred Reactor Driven by a Dual Punched Rigid-Flexible Impeller

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
Deyin Gu ◽  
Zuohua Liu ◽  
Facheng Qiu ◽  
Jun Li ◽  
Changyuan Tao ◽  
...  
Keyword(s):  
Reference Frames ◽  
Cfd Simulation ◽  
Energy Dissipation Rate ◽  
Solid Particles ◽  
Stirred Tank ◽  
Two Phase ◽  
Stirred Reactor ◽  
Solid Suspension ◽  
Computational Fluid Dynamics Cfd ◽  
Solid Liquid

Abstract Solid suspension characteristics were predicted by computational fluid dynamics (CFD) simulation in a stirred tank driven by a dual rigid-flexible impeller and a dual punched rigid-flexible impeller. An Eulerian-Eulerian approach, standard k-ε turbulence model, and multiple reference frames (MRF) technique were employed to simulate the solid-liquid two-phase flow, turbulent flow, and impeller rotation in the stirred tank, respectively. The CFD results showed that dual punched rigid-flexible impeller could increase the axial velocity and turbulent kinetic energy dissipation rate, and decrease the quantity of sediment solid particles compared with dual rigid-flexible impeller. Less impeller power was consumed by dual punched rigid-flexible impeller compared with dual rigid-flexible impeller at the same impeller speed. It was found that punched rigid-flexible impeller was more efficient in terms of solid suspension quality than dual rigid-flexible impeller at the same Pw. The simulated results for the axial solid concentration were in good agreement with the experimental data.

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