scholarly journals An experimental and numerical study of the particle dispersion in a ventilated room

2006 ◽  
Author(s):  
M. Gustiuc ◽  
T. Denes ◽  
S. El Hamdani ◽  
K. Limam ◽  
I. Colda
Keyword(s):  
Numerical Study ◽  
Particle Dispersion

scholarly journals Effect of Air Exchange Rate on Particle Decay in a Cleanroom: A Numerical Study

2019 ◽  
Vol 111 ◽  
pp. 01037
Author(s):  
Yunus Emre Cetin ◽  
Mete Avci ◽  
Orhan Aydin
Keyword(s):  
Exchange Rate ◽  
Turbulence Model ◽  
Recovery Time ◽  
Numerical Study ◽  
Particle Dispersion ◽  
Discrete Phase Model ◽  
Governing Equations ◽  
Air Exchange Rate ◽  
Particle Decay ◽  
Discrete Phase

In this study, particle decay in a cleanroom is investigated numerically. A commercial CFD package, FLUENT, is used in the analysis. The governing equations are solved by using the k-å turbulence model. For particle dispersion, the discrete phase model (DPM) is applied. Four different air change rates (3-10-25-43 ACH) with three particle diameters (0,5-5-10 ìm) are considered. It is shown that 10 ACH satisfies the needs in terms of recovery time.

scholarly journals On the Numerical Study of Indoor Particle Dispersion and Spatial Distribution

2012 ◽  
Vol 5 ◽  
pp. ASWR.S8113 ◽  
Author(s):  
Jianbo Jiang ◽  
Xinlei Wang
Keyword(s):  
Spatial Distribution ◽  
Particle Concentration ◽  
Numerical Study ◽  
Turbulence Models ◽  
Passive Scalar ◽  
Particle Dispersion ◽  
Phase Model ◽  
Particle Phase ◽  
Discrete Particle ◽  
Flow Models

In this paper, particle dispersion and spatial distribution in a full scale (5.5 m x 2.4 m x 3.7 m) forced ventilated room are investigated using four different multiphase flow models, including passive scalar model, discrete particle phase model, mixture model and Eulerian model. The main differences between these four models lie in how the particles are modeled. A two layer k-∊ turbulence model is used to calculate airflows. Simulated airflow characteristics and particle concentration are compared with corresponding experimental data. The results show that only discrete particle phase model could predict particle concentration distribution close to experimental values and satisfy the published validation criteria (ASTM D5157-97). The reasons for the failure and success of these models in the present case are discussed. Furthermore, the effects of turbulence models of airflows and treatment of boundary conditions on the particle concentration are also investigated.

A Numerical Study on Airflow and Particle Dispersion within an Urban Street Canyon with Different Wedge-Shaped Roofs

2013 ◽  
Vol 869-870 ◽  
pp. 213-217
Author(s):  
Yakup Parida ◽  
Wen Rong He ◽  
Zhong Hua Zhou ◽  
Deng Feng Fu
Keyword(s):  
Street Canyon ◽  
Stokes Equations ◽  
Numerical Study ◽  
Distribution Patterns ◽  
Particle Dispersion ◽  
Atmospheric Environment ◽  
Navier Stokes ◽  
Urban Street Canyon ◽  
Urban Street ◽  
Pollution Levels

This work presents a numerical study on airflow and particle dispersion within an urban street canyon with different wedge-shaped roof. A two-dimensional computational fluid dynamics (CFD) model for evaluating the airflow and particles dispersion within a street canyon was built up, which was based on the incompressible Reynolds Averaged Navier-Stokes equations, turbulence model and the particles transportation equation. It is revealed that: (1) particles dispersion inside an urban street canyon is mostly dominated by the in-canyon wind flow; (2) different wedge-shaped roof configurations causes a variety of particles distribution patterns; (3) air pollution levels are much higher in the step-down canyons relative to the step-up canyons; (4) the simulated result of FLUENT is reasonable, and the prospect of applying FLUENT to study atmospheric environment is very well. Key words: CFD; street canyon; particle dispersion; numerical simulation

scholarly journals Particle behavior in a turbulent flow within an axially corrugated geometry

2021 ◽  
Vol 13 (8) ◽  
pp. 168781402110360
Author(s):  
Ghulam Mustafa Majal ◽  
Lisa Prahl Wittberg ◽  
Mihai Mihaescu
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Stokes Number ◽  
Particle Dispersion ◽  
Particle Behavior ◽  
Eddy Simulation ◽  
Recirculation Zones ◽  
Pipe Geometry ◽  
Turbulent Gas Flow ◽  
Inflow Conditions

In this numerical study particle behavior inside a sinusoidal pipe geometry is analyzed. The 3D geometry consists of three identical modules, with a periodic boundary condition applied to the flow in the stream wise direction. The incompressible, turbulent gas flow is modeled using a Large Eddy Simulation (LES) approach. Furthermore, the particle dynamics are simulated using a Lagrangian point force approach incorporating the Stokes drag and slip correction factor. Four different sizes of particles, corresponding to a Stokes number less than unity, are considered along with two different inflow conditions: continuous and pulsatile. The pulsatile inflow has an associated flow frequency of 80 Hz. The fluid flow through the sinusoidal pipe is characterized by weak flow separation in the expansion zones of the sinusoidal pipe geometry, where induced shear layers and weak recirculation zones are identified. Particle behavior under the two inflow conditions is quantified using particle dispersion, particle residence time, and average radial position of the particle. No discernible difference in the particle behavior is observed between the two inflow conditions. As the observed recirculation zones are weak, the particles are not retained within the cavities for a long duration of time, thereby reducing their likelihood of agglomerating.

scholarly journals Numerical Simulation of Particulate Two-Phase Flows in Curved Pipeline Geometries

1996 ◽  
Author(s):  
S. Naik
Keyword(s):  
Numerical Study ◽  
Particle Dispersion ◽  
Phase Flow ◽  
Fluidised Bed ◽  
Phase Slip ◽  
Gas Turbine Combustor ◽  
Two Phase ◽  
Solid Mixture ◽  
Solid Fuel Combustion ◽  
Particle Momentum

The flow of particulate two-phase flow mixtures occur in several components of solid fuel combustion systems, such as the Pressurised Fluidised Bed Combustors (PFBC) and suspension fired coal bailers. A detailed understanding of the mixture characteristics in the conveying component can aid in refining and optimising its design. In this study, the flow of an isothermal, dilute two-phase particulate mixture has been examined in a high curvature duct, which can be representative of that transporting the gas-solid mixture from the hot clean-up section to the gas turbine combustor in a PFBC plant. The numerical study has been approached by utilising the Eulerian-Lagrangian methodology for describing the characteristics of the fluid and particulate phases. By assuming that the mixture is dilute, the governing particle momentum equations have been solved with appropriately prescribed boundary conditions. The influence of the turbulence on the particle dispersion was represented by a stochastic model. For the turbulent flow condition examined, it was observed that mixtures with small particle diameters had low inter-phase slip velocities and low impaction probability with the pipe walls. Increasing the particle diameters (> 50 um) resulted in higher inter-phase slip velocities and as expected their impaction probability with the pipe walls was significantly increased. The particle dispersion is significant for the smaller sizes whereas the larger particles are relatively insensitive to turbulence. The main particle impaction region, and location most prone to erosion damage, is estimated to be within an outer duct length of 2 to 5 times the duct diameter.

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