Page 134 - Air Pollution Control Engineering
P. 134
03_chap_wang.qxd 05/05/2004 12:48 pm Page 113
Cyclones 113
Fig. 5. Collection efficiency as a function of particle diameter, for three entry velocities:
curves obtained from the Leith and Licht model (9) and experimental points from Dirgo and
Leith (17).
)(
(
9 1.8 10 kg ms 0.0906m s) 0.5
×
−
5
3
D =
50 860kg m )( )( 2
( π 1.057 m 15.8m s)
3
µ
−
6
D = 4.5 × 10 m = 4.5 m
50
The exponent β is a function of the cut diameter (in centimeters) and of the cyclone
dimensions [Eq. (30)]. It is therefore implicitly dependent on the gas entry velocity:
( 0.151 )(0.060 )
ln β= 0.62 − 0.87 ln(4.5 × 10 −4 ) + 5.21 ln 2
(0.302 )
( 0.151 )(0.060 ) 2
+ 1.05 ln 2
(0.302 )
β= 2.44
Therefore, the grade efficiency [Eq. (23)] at 10.0 m/s can be written as
η = 1 , with D in micrometers.
i [ 1+ (4.5 D i ) 2.44 ] i
For v = 15 m/s, the vortex diameter and length, d and Z , do not depend on the entry
i c c
velocity. Thus, the calculated values hold:
