$(8$pts$)$ A cyclone separator has an inlet width of $0\mathrm{.}75m,Vc=20\frac{m}{s}$ and $N=10$

$($a$)$ Estimate the cut diameter for this cyclone separator for the block flow model

$($b$)$ Estimate the collection effficiency of this cyclone separator for particles with diameter of

$2\mathrm{.}5$ um under the block flow model