Comparative study of the continuous phase flow in a cyclone separator using different turbulence models

2005 ◽  
Vol 48 (11) ◽  
pp. 1175-1197 ◽  
Author(s):  
H. Shalaby ◽  
K. Pachler ◽  
K. Wozniak ◽  
G. Wozniak
Keyword(s):  
Comparative Study ◽  
Turbulence Models ◽  
Continuous Phase ◽  
Phase Flow ◽  
Cyclone Separator

CFD Prediction of Gas-Liquid Separation Efficiency of Geothermal Steam-Water Cyclone Separator Using a Verified Turbulence Model

2017 ◽  
Author(s):  
Xidong Hu ◽  
Shaoxiang Qian ◽  
Kaori Yamauchi ◽  
Haruo Okochi
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Separation Efficiency ◽  
Turbulence Models ◽  
Phase Flow ◽  
Cyclone Separator ◽  
Steam Quality ◽  
Rsm Model

The present paper aims to predict the separation efficiency and pressure drop of a vertical geothermal cyclone type separator using CFD (Computational Fluid Dynamics) simulations, for optimizing the design of such separator. A benchmark study was firstly performed for a single phase flow in a Stairmand design cyclone using four different turbulence models, in order to verify the prediction accuracy of flow velocity distribution by comparison with experimental data in literature. The investigated turbulence models include (1) Renormalization Group (RNG) k-ε, (2) Realizable k-ε, (3) Reynolds stress turbulence model (RSM) and (4) Large eddy simulation (LES). Results show that RNG k-ε and Realizable k-ε models are not capable of reproducing the experimental data while the RSM and LES models reproduce the flow velocity distribution very well. Then, CFD simulations of two-phase flow in a steam-water cyclone separator were carried out for different stream inlet velocities applying the RSM model. This is based on the consideration that steady state analysis can be done for the RSM model, and however, transient analysis is needed for the LES model, and hence, more expensive and time-consuming for engineering applications. The CFD results for outlet steam quality and pressure drop were obtained under different stream inlet velocities. The separation efficiency and outlet steam quality decreases a little when the inlet velocity increases from 34.5m/s to 72m/s. However, the outlet steam quality predicted in the present CFD analysis is close to that of Lazalde-Crabtree.

scholarly journals Particulate Matter Dispersion Modeling in Agricultural Applications: Investigation of a Transient Open Source Solver

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2246
Author(s):  
David Janke ◽  
Senthilathiban Swaminathan ◽  
Sabrina Hempel ◽  
Robert Kasper ◽  
Thomas Amon
Keyword(s):  
Particulate Matter ◽  
Open Source ◽  
Turbulence Models ◽  
Continuous Phase ◽  
Experimental Chamber ◽  
Dispersion Modeling ◽  
Reynolds Stresses ◽  
Agricultural Applications ◽  
Inflow Turbulence ◽  
Turbulence Generator

Agriculture is a major emitter of particulate matter (PM), which causes health problems and can act as a carrier of the pathogen material that spreads diseases. The aim of this study was to investigate an open-source solver that simulates the transport and dispersion of PM for typical agricultural applications. We investigated a coupled Eulerian–Lagrangian solver within the open source software package OpenFOAM. The continuous phase was solved using transient large eddy simulations, where four different subgrid-scale turbulence models and an inflow turbulence generator were tested. The discrete phase was simulated using two different Lagrangian solvers. For the validation case of a turbulent flow of a street canyon, the flowfield could be recaptured very well, with errors of around 5% for the non-equilibrium turbulence models (WALE and dynamicKeq) in the main regions. The inflow turbulence generator could create a stable and accurate boundary layer for the mean vertical velocity and vertical profile of the turbulent Reynolds stresses R11. The validation of the Lagrangian solver showed mixed results, with partly good agreements (simulation results within the measurement uncertainty), and partly high deviations of up to 80% for the concentration of particles. The higher deviations were attributed to an insufficient turbulence regime of the used validation case, which was an experimental chamber. For the simulation case of PM dispersion from manure application on a field, the solver could capture the influence of features such as size and density on the dispersion. The investigated solver is especially useful for further investigations into time-dependent processes in the near-source area of PM sources.

scholarly journals Prediction Models of Droplet Characteristics Based on the Locally Convergent Configurations in PMMA Microchips

2021 ◽  
Vol 2097 (1) ◽  
pp. 012027
Author(s):  
Zhongxin Liu ◽  
Zhiliang Wang ◽  
Chao Wang ◽  
Jinsong Zhang
Keyword(s):  
Flow Rate ◽  
Relative Position ◽  
Prediction Models ◽  
Continuous Phase ◽  
Lubricating Oil ◽  
Flow Rate Ratio ◽  
Phase Flow ◽  
Exponential Relationship ◽  
Two Phase ◽  
Relationship Of

Abstract This paper novel designed the local convergence configuration in the coaxial channels to study the two-phase flow (lubricating oil (continuous phase, flow rate Q c)/deionized water (dispersed phase, flow rate Q d)). Two geometric control variables, the relative position (x) and tapering characteristics (α), had the different effects on the droplet formation. The increase of relative position x caused the higher frequency and finer droplets, and the increase of convergence angle α, took the opposite effects. The results indicated that the equivalent dimensionless droplet length Ld/Wout and the flow rate ratio Qd/Qc had an exponential relationship of about 1/2. Similarly, it was found that the dispersed droplets generating frequency and the two-phase capillary number, CaTP = uTPμc/σ, had an exponential relationship. The advantage of the convergent configurations in micro-channel was the size and efficiency of droplet generation was very favorable to be controlled by α and x.

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