A settling chamber is used for the removal of discrete particulate matter from air with following conditions. Horizontal velocity of air =0.2 m/s; Temperature of air stream =77°C: Specific gravity of particle to be removed =2.65; Chamber length =12m Chamber height =2 m; Viscosity of air at 77°C=2.1×10^-5 kg/m.s Acceleration due to gravity (g)=9.81 m/s² Density of air at 77°C=1.0 kg/m³ Assume the density of water as 1000 kg/m³ and Laminar condition exists in the chamber.
The minimum size of particle that will be removed with 100% efficiency in the settling chamber (in μm) is ______ (round off to one decimal place).