Computer Modeling of Air Flow and Contaminant Transport in Environments and Electrophotographic Machines (Goodarz Ahmadi and Fa-Gung Fan)

CAMPClarkson UniversityCAMPCAMP

Clarkson UniversityClarkson University



• Environmental Applications- Respiratory Deposition- Aerodynamic Lenses- Airflow near and in Buildings- Airflow and pollutant near Bridges

• EHD in Corona Devices- Electrostatic Separator- Corotron Devices

•• Environmental ApplicationsEnvironmental Applications-- Respiratory DepositionRespiratory Deposition-- Aerodynamic LensesAerodynamic Lenses-- Airflow near and in BuildingsAirflow near and in Buildings-- Airflow and pollutant near BridgesAirflow and pollutant near Bridges

•• EHD in Corona DevicesEHD in Corona Devices-- Electrostatic SeparatorElectrostatic Separator-- CorotronCorotron DevicesDevices



• particle and fiber depositionin human lung and nose

•• particle and fiber depositionparticle and fiber depositionin human lung and nosein human lung and nose Hopke-NIOSHHopkeHopke--NIOSHNIOSH



U=3m/s45o

2cm

7.2cm

2.78cm 30o

45o

1.46cm

3.01cm

1.5cm

0.95cm

Grid schematic Grid schematic

• Particle and fiber deposition in human lung•• Particle and fiber deposition in human lungParticle and fiber deposition in human lung

Schematic of the triple Schematic of the triple bifurcation airway bifurcation airway

FLUENTFLUENTFLUENT



Velocity vector plotVelocity vector plot Particle DepositionParticle Deposition



10-2 10-1 1000

10

20

30

40

50

st

Second Bifurcation

Third Bifurcation

First Bifurcation

Variations of the capture efficiency Variations of the capture efficiency with particle Stokes number with particle Stokes number

100 10110

20

30

40

50

60

70

80

Particle Diameter

Numerical Simulation

Experimental Data

(µm)

(%)

Comparison of total deposition with Comparison of total deposition with the experimental data of Hinds (1982) the experimental data of Hinds (1982)



η(%

)

Velocity magnitude Velocity magnitude contourscontours

Li and Ahmadi (1996) Li and Ahmadi (1996)



Velocity magnitude contours in Velocity magnitude contours in the nose.the nose.



Pressure contours in Pressure contours in the nose.the nose.



Diameter in Micron

Dep

ositi

onin

Per

cent

age

0 2 4 6 8 100

10

20

30

40

50

60

70

80

90

100 3.75 L/min7.5 L/min15 L/min

τ*

Dep

ositi

onin

Per

cent

age

0.1 0.2 0.3 0.410

20

30

40

50

60

70

80

90

100



Sample Deposited Sample Deposited Glass FibersGlass Fibers

Sample Sample TrajectoriesTrajectories

Comparison with Comparison with Experimental Experimental

DataData

Fan and Ahmadi (1996)Fan and Ahmadi (1996)SoltaniSoltani and Ahmadi (1999)and Ahmadi (1999)



Skimmer

Intermediate Chamber

Nozzle (d=3 mm)

Vacuum Pump

50 mm

Aerodynamic Lenses (d=5, 4.5, 4, 3.75, 3.5 mm)

Velocity Contours

Computational grid

••To evaluate the performance To evaluate the performance of aerodynamic lenses for of aerodynamic lenses for generating focused beams of generating focused beams of nanonano--particlesparticles



Particle Trajectories

d =100 nm

Pressure Contours

0.00 0.05 0.10 0.15 0.20 0.25Particles Diameter (micrometer)

0

4

8

12

16

20

Par

ticle

Bea

m D

iam

eter

(mm

)Experimental Data (Liu et al. 1995b)

Conningham (varying pressure)

Conningham (constant coefficient)

Bea

m D

iam

eter

(mm

)

Particle Diameter (µm)



Experimental helium Experimental helium concentration data concentration data

measured by measured by MirzaiMirzai et et al. (1994)al. (1994)

Computer Simulation of Computer Simulation of concentration behind the buildingconcentration behind the building



Velocity magnitude contours.Velocity magnitude contours.

Pollutant concentration contours.Pollutant concentration contours.



LwebugaLwebuga--MukasaMukasa (2001)(2001)

BuffaloBuffalo

CanadaCanada



BuffaloBuffalo

CanadaCanadaPeace BridgePeace Bridge

LwebugaLwebuga--MukasaMukasa (2001)(2001)



30%50 µm

8%20 µm

6%0.1 µm

Deposition Rate

Particle Size

Velocity magnitude contoursVelocity magnitude contours



PoF

lF

tF

tM

O

a

d

••Cryogenic Surface CleaningCryogenic Surface Cleaning((ToscanoToscano and Ahmadi (2002)and Ahmadi (2002)

••Particle Removal in TurbulentParticle Removal in TurbulentFlows Flows ((SoltaniSoltani, Fan and Ahmadi (1995), Fan and Ahmadi (1995)

••Removal by Vibration Removal by Vibration



Fully Coupled ElectroFully Coupled Electro--hydrodynamic hydrodynamic System of Equations are solvedSystem of Equations are solved



GasGasFlowFlow Corona WireCorona Wire

PlatePlate

PlatePlate



ElectrodeElectrode

+ WireWire

Ionized SheathIonized Sheath

Positive IonPositive IonNegative Ion/Negative Ion/ElectronElectron



GasGasFlowFlow Corona WireCorona Wire

PlatePlate

PlatePlate

Single Wire PrecipitatorSingle Wire Precipitator

Kaptsov’sKaptsov’s Assumption and Assumption and PeekPeek’’s Formula were useds Formula were used





No Cross FlowNo Cross Flow









0 0.25 0.5 0.75 1Y (dimensionless)

0

5

10

15

20

25

Vol

tage

(dim

ensi

onle

ss) Computational result

Penny and Matick


0

3

6

9

12

Vol

tage

(dim

ensi

onle

ss)



No cross-flow Inlet velocity 0.2 m/s

Intel velocity 3 m/s Inlet velocity 6 m/s




0

2

4

6

8

10

12

14

Vol

tage

(dim

ensi

onle

ss)

InletOutlet


0

2

4

6

8

10

12

14

Vol

tage

(dim

ensi

onle

ss)

InletOutlet


0

2

4

6

8

10

12

14

Vol

tage

(dim

ensi

onle

ss)

InletOutlet

No cross-flow


0

2

4

6

8

10

12

14

Vol

tage

(dim

ensi

onle

ss)

InletOutlet

Inlet velocity 0.2 m/s












Inlet Inlet VelocityVelocity

Plate Plate CurrentCurrent

No cross flow 5.84 e-5 A/m2

0.2 m/s 5.83 e-5 A/m2

3 m/s 5.70 e-5 A/m2

6 m/s 5.53 e-5 A/m2

Current received by Current received by each Plate each Plate

ypy bqEJ ∫=

Current FluxCurrent Flux

)( qDbqEquJ ∇−+=



Inlet VelocityInlet Velocity Wire Wire Charge Charge DensityDensity

No cross flow 5.64 e-5 C/m3

0.2 m/s 5.66 e-5 C/m3

3 m/s 5.73 e-5 C/m3

6 m/s 5.90 e-5 C/m3





Electric Potential and Charge Density ContoursElectric Potential and Charge Density Contours

Electric PotentialElectric PotentialContoursContours

Charge DensityCharge DensityContoursContours



0 100 200 300

Φ0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

0.0009

0.001

C/m

3

0 5 10 15 20Length (mm)

0

100

200

300

400

Vol

tage

(Vol

t)

Voltage Profile on the Voltage Profile on the SubstrateSubstrate

Charge Density Charge Density Profile on the wireProfile on the wire



•• Develop a sequence of interactive webDevelop a sequence of interactive web--based based courses on particle transport, deposition and courses on particle transport, deposition and removalremoval

•• Provide computational modeling experienceProvide computational modeling experience•• Provide handsProvide hands--on laboratory experienceon laboratory experience

http://www.clarkson.edu/fluidflow/courses/me437/syllabus.htm





•• Computer modeling provide an Computer modeling provide an important tool for studying important tool for studying environmental flowsenvironmental flows

•• Numerical simulation is a useful tool Numerical simulation is a useful tool for design of corona devices for design of corona devices

Goodarz Ahmadi Goodarz Ahmadi Clarkson University Clarkson University (315) 268(315) 268--2322 2322 [email protected]@clarkson.edu

FaFa--Gung Fan Gung Fan Xerox CorporationXerox [email protected]@crt.xerox.com

Technology

Computer Modeling of Air Flow and Contaminant Transport in Environments and Electrophotographic Machines (Goodarz Ahmadi and Fa-Gung Fan)