Encyclopedia of Environmental Science and Engineering, Volume I and II

0.001

10 –8

10 –7

10 –6

10 –5

10 –4

10 –3

10 –2

10 –1

100

0.01 0.1 1 10

Dp (mm)

Kelvin

effect,

(water

droplet)

Relaxation time

C

c at 10mm Hg

Diffusion coeff., D

(n

p =1

)

Pulse height(example)

Slip coeff., C

c

τg

at 10mm H

g

τg

1°C/cm

Vth

Average absolute value of Brownian

displacement in 1s,

∆X in air

20°C in air

1atm

10 mm Hg

Settling velocity, V

t

In air (

p=1g cm

–3)

1

10

10 –2

10 –1

100

101

102

100

1000

1

2

3

4

5

6

7

8

Slip coefficient, C

c

Pulse height (light scattering)

Increase in vapor pressure by Kelvin effect, p

/d

p

Settling velocity v

(cm/s), Diffusion coefficient D (cmt

2 /s),

Relaxation time

τg

(s), Electrical mobility B

(cme

2 V

–1

s

–1

),

Average absolute value of Brownian displacement in 1s

∆x

=

4D/

p

(cm),

Thermophoretic velocity v

th

(cm/s)

Vt =

( p – (^) f)gDpCc
18 m
18 m
(3.1)
(3.4)
(3.6)
(3.8)
Cc = 1 + 2.514 (^) Dλ
p
λ Dp
Dp λ

• 0.80 exp (–0.55 ) (3.2)
  (3.3)
  (3.5)
  (3.7)
  Cc=1+(2 / pDp) [6.32 + 2.01 exp (–0.1095pDp)] p in cm Hg, Dp in^ mm
  ∆x = 4Dt D = kTCc
  τg =
  pDpCc
  Be =
  np e Cc
  Pd / P 8 = exp ( 4Mσ
  RT lDp
  )
  =1g cmp
  –3
  Electrical mobility, B
  e
  3 pmDp
  3 pmDp
  ρ
  ρ
  ρ
  ρ^2
  2
  ρ
  ρ
  8
  p
  FIGURE 3 Fundamental mechanical and dynamic properties of aerosol particles suspended in a gas.
  AEROSOLS 19
  C001_002_r03.indd 19C001_002_r03.indd 19 11/18/2005 10:09:10 AM11/18/2005 10:09:10 AM