M E 433
Professor John M. Cimbala
Today, we will:
•
Discuss air cleaners in series and parallel
Lecture 30
Example: Lapple Cyclones in Series and Parallel
Given: Dusty air is cleaned by one large
Lapple cyclone in series with four smaller
Lapple cyclones in parallel. Details:
In
Cleaner 1
•
particle density ρp = 1500 kg/m3
E1
•
bulk flow rate of air Q = 0.111 m3/s
•
air at STP: ρ = 1.184 kg/m3,
µ = 1.849 × 10-5 kg/(m s)
•
Dp,cut, 1 = 10 microns; Dp,cut, 2 = 2.5 microns
Cleaner 2, E2
Cleaner 2, E2
Out
Cleaner 2, E2
Cleaner 2, E2
To do: Calculate the overall removal efficiency of 2.0-µm particles. Give your answer in
percentage to 3 significant digits. Some equations are provided here for convenience.
Parallel:
Series:
m
m
Qj


E ( Dp )
1 − ∑ f j 1 − E ( Dp ) , f j =
1 − ∏ 1 − E ( D p ) 
=
E ( Dp )
=
overall
j
overall
j


Qtotal
j =1
j =1
Lapple: E ( D p ) =
Solution:
1
 D
1+  p
D
 p ,cut



−2