Question 1 Air is being used as a fluidizing medium in a bed of silica gel having particle fractions in the following range: Fraction (mm) -2+1.5 -1.5 +1.0-1.0+0.5 -0.5+0.25 Content (% mass) (45) (25) (18) (12) The (-) sign denotes oversize particles. The temperature of air is 413 K. Determine: (a) Critical velocity of the air; (b) Working velocity of the air (c) Actual velocity of the air Given: SILICA GEL FLUIDIZATION NUMBER = 1.62 Bulk density of silica gel = 650 kg/m Particle density = 1100 kg/m Air Dynamic viscosity = -23.7x 10 kg/m.s Air Density 0.854 kg/m 3