Four-Phase Eulerian-Eulerian Model for Prediction of Multiphase Flow in Cyclones

Abstract

The purpose of this work is to present a new code, the CYCLO-EE 3 , which is based on computational fluid dynamics (CFD) techniques. The model used is based on the Eulerian-Eulerian approach and it is composed of several time differential equations in a 3-D-space domain with a 3-D symmetric cyclone inlet. The solid phase is treated like a hypothetical fluid and drag forces between phases are responsible for the gas-solid interaction. The CYCLO-EE 3 code makes possible the use of up to three solid phases, each one with size of particle, density and specific volumetric fraction. The mathematical model is completed using a hybrid turbulence model composed of the combination of the (k-ε) standard model and Prandtl's longitudinal mixing model to represent the turbulence of the gas phase. The model is solved using the finite volume method with staggered grids in the cylindrical coordinate system. The numerical results allowed prediction of the pressure drop and the collection efficiency as well as the complete fluid dynamic behavior of the gas-solid flow for the cyclone. The collection efficiency and pressure drop from an experimental study reported by literature were used to validate the model. A comparison between the experimental data and the numerical results shows that the CYCLO-EE 3 code predicts the results well.

CFD Modeling of Gas–Solid Cyclone Separators at Ambient and Elevated Temperatures

“…E-E studies of gas-solid cyclone separators are very scarce, with the early investigations being allotted to the prediction of the change of cyclone hydrodynamics with the addition of particles [67,123]. In most of the existing E-E studies of gas-solid cyclones, the comparison with experimental data is carried out for cyclones operating with very low particle mass loadings [124][125][126], i.e., below 0.01 kg s /kg g , while the true advantage of using the E-E approach is for the high loading of particles. Costa et al [126] implemented an E-E simulation of gas-solid flow in a cyclone with four-way coupling.…”

Numerical Investigation of Cyclone Separators: Physical Mechanisms and Theoretical Algorithms

“…Despite their apparent simplicity, the internal flow behavior of cyclones is exceedingly complex, especially in the case of gas-particle flow, due to the three-dimensional nature of the flow, vortex breakdown, flow reversal, strong anisotropy, and interactions between flow phases. Despite several decades of research, the high turbulence intensity makes it challenging to -----understand the flow behavior [6,[11][12][13]. Cyclones can provide high separation efficiency, up to 99 % for particles larger than 5 mm, which is influenced by several factors, including the inlet flow velocity and particle mass loading ratio [14,15].…”

Modeling and Performance Analysis of Different Gas–Bioparticle Cyclone Separators: CFD–DEM Simulations

“…For instance, it is ineffective in eliminating very fine particles less than 10 μm, and its capacity to handle high volumes of gas or air streams can be limited, causing it to become less effective when overwhelmed. 5 The industrial cyclone separator is designed with a reverse flow, consisting of a cylindrical and conical body made of metal and an inlet and outlet for the gas or air stream, as shown in Figure 1. The gas or air stream enters the separator tangentially at the top of the body, creating a swirling motion inside the cylinder.…”

“…It boasts high efficiency, with up to 99% removal rates for particles as small as 10 μm, making it an environmentally friendly option that eliminates the need for chemicals or consumables. − Nonetheless, the device has certain limitations. For instance, it is ineffective in eliminating very fine particles less than 10 μm, and its capacity to handle high volumes of gas or air streams can be limited, causing it to become less effective when overwhelmed . The industrial cyclone separator is designed with a reverse flow, consisting of a cylindrical and conical body made of metal and an inlet and outlet for the gas or air stream, as shown in Figure .…”

“…For instance, it is ineffective in eliminating very fine particles less than 10 μm, and its capacity to handle high volumes of gas or air streams can be limited, causing it to become less effective when overwhelmed. 5 The industrial cyclone separator is designed with a reverse flow, consisting of a cylindrical and conical body made of metal and an inlet and outlet for the gas or air stream, as shown in Figure 1 centrifugal forces, the heavier solid or liquid particles are thrown toward the cylinder walls, where they collect and are removed, while the light particles with the air stream escape from the tube at the top surface of the cyclone. 2,6,7 Most of the cyclone dimensions are typically expressed as ratios to the cyclone diameter (D), allowing for the straightforward development of such standard designs, including 1D3D, 8 2D2D, 9 and 1D2D, 10 where each number before (D) refers to the length of the cylindrical and conical sections.…”