11. The collection efficiency by interception increases with the
A. increasing particle diameter
B. increasing airflow velocity
C. both (a) and (b)
D. increasing particle size
12. For indirect heating, the plate and frame heat exchanger is generally more effective than the shell and tube heat transfer due to its
A. larger heat transfer area
B. smaller heat transfer area
C. lesser cost
D. more number of plates
13. The mechanism of air filtration in the fibrous filter is
A. electrostatic attraction
B. impaction
C. interception
D. all of these
14. If the packing density (α) is defined as the volume of the fiber unit volume of the filter bed, the velocity within the filter void space is equal to (where V is the velocity in fluid void space and V0 is undisturbed fluid velocity)
A. V = V0/(1-α)
B. V–V0= 1 – α
C. V = V0(1 – α)
D. V = V0/(1 + α)
15. For the turbulent flow, the dispersion coefficient is correlated as a function of
A. Reynolds number
B. Sherwood number
C. Schmidt number
D. Grashof number