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Gaseous And Particulate Dispersion In Street Canyons Kambiz Nazridoust Department of Mechanical and Aeronautical Engineering Clarkson University, Potsdam,

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Presentation on theme: "Gaseous And Particulate Dispersion In Street Canyons Kambiz Nazridoust Department of Mechanical and Aeronautical Engineering Clarkson University, Potsdam,"— Presentation transcript:

1 Gaseous And Particulate Dispersion In Street Canyons Kambiz Nazridoust Department of Mechanical and Aeronautical Engineering Clarkson University, Potsdam, NY

2 1.Develop A Numerical Model in FLUENT™ Code Coupled with Different Turbulence Models to Simulate the Fluid Flow, Pollutant Dispersion and Particle Deposition inside the Street Canyons 2.Examine the Accuracy of Major Turbulence Models with Experimental Data for Street Canyon Modeling 3.Examine Gaseous Air Pollution from Vehicular Exhaust and Industries inside the Street Canyons 4.Examine Particulate Transport and Deposition in Street Canyons for Different Particle Sizees and Flow Conditions Objectives

3 Model Schematic b (m)h (m)w (m)L (m)H (m) 2D, Exact (Wind Tunnel Model) D, Symmetric D, Asymmetric 2010, 15, D,Variable Street Width 20, 40, 6010, 15,

4 Computational Grid

5 Boundary Conditions Plane of Symmetry Outflow1/7 th power inlet velocity Vehicular Emission Line Source Q=4 lit/h All walls: -No slip velocity boundary condition -Zero Diffusive Flux -Stick upon impact Leeward Windward

6 Governing Equations Continuity: Momentum: Reynolds Stress Transport Model:

7 CO 2 Concentration –Asymmetric Canyon Configuration Flow Field Results

8 Stream Functions(m 2 /s 2 ) inside the Canyons for Different Wind Velocities Flow Field Results

9 Velocity Vector Field inside the Canyons for Different Wind Velocities Flow Field Results

10 CO 2 Concentration inside the Canyons for Different Wind Velocities Flow Field Results

11 Turbulence Intensity(%) inside the Canyons for Different Wind Velocities Flow Field Results

12 Wind Tunnel Experiment Computational Grid of the Exact Dimensions of the Wind Tunnel Experiment Measurement Points of Wind Tunnel Experiment by Meroney et al. (1996)

13 (a) Leeward (b) Windward Comparison with Wind Tunnel Experiment

14 (a) 1 st Roof (b) 2 nd Roof Comparison with Wind Tunnel Experiment

15 Particulate Emissions Particulate Injector: Spherical Carbon Particles m/s (for 4 lit/h volumetric flux) -3nm to 10micron All walls: -No slip velocity boundary condition -Stick upon impact LeewardWindward

16 Particulate Emissions Particle Relaxation time Stokes-Cunningham Slip Correction Factor Stokes Number Capture Efficiency Motion of Spherical Particle

17 Particle Capture Efficiency vs. Particle Diameter for Different Surfaces Particulate Deposition Patterns (a) Windward Wall; (b) Leeward Wall; (c) Roofs; (d) Road

18 Particle Capture Efficiency vs. Stokes Number for Different Wind Velocities Particulate Deposition Patterns

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21 Future Work

22 Computational Model

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24 Flow Field Results

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29 1. The present simulation has reasonable agreement with the experimental data from wind tunnel experiment performed by Meroney et al (1996). 2. Among the turbulence models used in this study, Reynolds Stress Transport model (RSTM) shows better agreement with experiment in most of the cases. 3.For higher wind speeds less gaseous emission will happen on the walls of the buildings. 4.Particle transport and deposition on the surfaces depend on the wind speed and size of the particles. 5.Particle deposition is controlled by Brownian motion for low velocities and Gravity for large particles. Conclusions


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