Calculate $u_{mf}$ for a bed of irregular particules $($take $d_p=d_{scr}*{}_s)$ fluidized by air at about $20$

$C$ and $1$atm.

Data

Solids: $d_{scr}=100m,{}_s=0\mathrm{.}63,{}_s=5,000k\frac{g}{m^3}$

Bed voidage: ${}_m={}_{mf}=0\mathrm{.}6($estimated$)$