COMPUTATIONAL MODELING OF PARTICLE TRANSPORT IN TURBULENT AIRFLOW Goodarz Ahmadi ahmadi@clarkson.edu Department of Mechanical and Aeronautical Engineering Clarkson University, Potsdam, NY 13699-5725

Air Pollution and Human Health Flow Around Buildings Outline Air Pollution and Human Health Flow Around Buildings Airflow in Street Canyons Pollution near Peace Bridge Lung and Nose Deposition Particle Resuspension (DNS) Conclusions

Gas-to-Particle Conversion (Sulfate, Nitrate, …) Atmospheric Aerosols Sources of Particles Natural (480-2,200106 Tons/yr) Soil Dust Forest Fire Volcanic Activities Sea Salts Gas-to-Particle Conversion (Sulfate, Nitrate, …)

Industrial Activities Agriculture Atmospheric Aerosols Sources of Particles Man-Made (185-420106 Tons/yr) Vehicle Exhaust Energy Production Industrial Activities Agriculture Motor Vehicles

Respiratory Problems (Asthma) Heart Disease Cancer Health Effects Respiratory Problems (Asthma) Heart Disease Cancer Increase in Mortality Disease Transmission Bio-aerosols

Turbulent Boundary Layer Turbulent Flows Turbulent Boundary Layer Turbulent Jet Flows

Turbulent Flow Simulation Direct Numerical Simulation Large Eddy Simulation Stress Transport model k- Model (Two-Equation) One-Equation Model Mixing Length Models

Instantaneous Fluctuation Velocity Simulation Direct Numerical Simulation Subgrid Scale Simulation Gaussian Models Pdf – Based Model

Instantaneous Fluctuation Velocity Simulation Instantaneous Velocity Thompson (1987) Lagrangian Time Macro-Scale

Particle Equation of Motion Assumptions: Dilute Flows, One-Way Interaction, Neglect Particle Collisions

CRCD Web-Based Course Module Brownian Dispersion CRCD Web-Based Course Module

Particle Deposition in a Duct g He and Ahmadi (1999)

Airflow Velocity Vector Field Near a Building

Simulated Helium Concentration Comparison of experimental helium concentration data of Mirzai et al. (1994) with the model prediction.

Airflow and Pollutant Transport in a Building Velocity magnitude contours. Pollutant concentration contours.

Airflow and Pollutant Transport in a Building

Airflow and Pollutant Transport in a Building Room Floor Room Vent Room Walls

Street Canyons

Triangular Grids for Symmetric & Asymmetric Street Canyons

Symmetric Street Canyon CO2 Concentration - Symmetric Street Canyon U∞ = 3 m/s U∞ = 5 m/s U∞ = 7 m/s U∞ = 20 m/s

Particle Dispersion Patterns - Symmetric Street Canyon

Symmetric Street Canyon CO2 Concentration - Symmetric Street Canyon U∞ = 3 m/s U∞ = 5 m/s U∞ = 20 m/s U∞ = 7 m/s

Wind Tunnel Experiment - Symmetric Street Canyon Meroney et al. (1996)

Particle Dispersion Patterns - Asymmetric Street Canyon

Peace Bridge Buffalo Canada Lwebuga-Mukasa (2001)

Schematics of Peace Bridge Buffalo

Geometric Features of Computational Domain Canada Buffalo Geometric features of the computational domain and the grid.

Airflow Velocity Contours Near Peace Bridge

Particle Trajectories of Emission from Peace Bridge.

Peace Bridge PARTICLE DEPOSTION 0.1 µm Particles

Lwebuga-Mukasa (2004)

Computational Grids

Computational Grids

Boundary Conditions

Emissions Dispersion

Respiratory Deposition particle and fiber deposition in human lung and nose

Schematic of the triple Lung Deposition Particle and fiber deposition in human lung U=3m/s 45o 2cm 7.2cm 2.78cm 30o 1.46cm 3.01cm 1.5cm 0.95cm Grid schematic Schematic of the triple bifurcation airway

Lung Deposition Velocity vector plot Particle Deposition

Mean Velocity Contours Velocity Magnitude Contours

Variations of the capture efficiency with particle Stokes number Lung Deposition Mazaheri and Ahmadi (%) Comparison of total deposition with the experimental data of Hinds (1982) Variations of the capture efficiency with particle Stokes number

Particle Dapture Efficiency-Comparison with Data

NASAL CAVITY CORONAL SECTIONS 1 mm 7 mm 13 mm 19 mm 25 mm 31 mm 37 mm 43 mm 49 mm 55 mm 61 mm 67 mm 73 mm 79 mm

NASAL MODEL

Axial Velocity Contours 4 L/min Vestibule Nasal valve Main airway 14 L/min Vestibule Nasal valve Main airway

Airflow Path Lines Zamankhan and Ahmadi and Co-Workers 2006

Nose Friction Coefficient

Comparison of Captrue Efficiency with Experimental Data Ultra fine Particles 10 L/min 4 L/min

Nosal Captrue Efficiency Versus Peclet Number Ultra fine Particles

Nosal Captrue Efficiency Versus Stokes Number Course Particles

Direct Numerical Simulations

Flow Between Two Parallel Plates Upper Wall Center Line Mean Flow Lower Wall

Intantaneous Velocity Field

Particle Removal Pattern

Fiber Transport and Deposition Comparison with Experimental Data Sample Deposited Glass Fibers Sample Trajectories Fan and Ahmadi (1996) Soltani and Ahmadi (1999)

Flexible Fibers

Flexible Fibers

Computer model could be used to test various scenarios. Conclusions Computer simulation provides insight into air pollution transport and deposition in indoor and outdoor environments. Computer model could be used to test various scenarios. Computer simulation is useful for studying the transport processes in human lung.

Thank You! Questions?