A. (Dp/6) (ε/1- ε)
B. (Dp/6) (1- ε/ε)
C. ⅔Dp (1- ε/ε)
D. ⅔Dp (ε/1- ε)
Related Mcqs:
- A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun’s equation for the above fluid-particle system (in SI units) is given below: Δ P/L = 375 × 103 VOM + 10.94 × 106 V2 OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?
A. 0.2
B. 0.5
C. 0.7
D. 0.8 - A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun’s equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 × 103 VOM + 10.94 × 106 V2 OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is_________________?
A. 12 mm/s
B. 16 mm/s
C. 24 mm/s
D. 28 mm/s - Bed pressure drop in an air fluidised bed of catalyst particles (ρp = 200 kg/m3, Dp = 0.05 cm) of 60 cm bed depth and bed porosity of 0.5 expressed in cm of water (manometer) is________________?
A. 90
B. 60
C. 45
D. 30 - A bed consists of particles of density 2000 kg/m3. If the height of the bed is 1.5 metres and its porosity 0.6, the pressure drop required to fluidise the bed by air is_________________?
A. 25.61 kPa
B. 11.77 kPa
C. 14.86 kPa
D. 21.13 kPa - For liquid flow through a packed bed, the superficial velocity as compared to average velocity through the channel in the bed is________________?
A. More
B. Less
C. Equal
D. Independent of porosity - A gas (density = 1.5 kg/m3, viscosity = 2 × 10‒5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5 kg/m3and viscosity of 3 × 10‒5kg/m.s flowing at 3 m/s will be________________?
A. 8400 Pa/m
B. 12600 Pa/m
C. 18900 Pa/m
D. 16800 Pa/m - A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is________________?
A. 4.4 KPa
B. 2.94 KPa
C. 3.7 KPa
D. None of these - For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as_________________?
A. d
B. d2
C. d4
D. d̅ 2 - The ratio of the hydraulic radius to the diameter of the channel, for maximum mean velocity of flow in a circular channel, in open channel flow is_________________?
A. 0.3
B. 0.9
C. 0.03
D. 0.66 - For Laminar flow through a packed bed, the pressure drop is proportional to (Vs is the superficial liquid velocity and Dp is the particle diameter) ?
A. Vs/Dp2
B. Vs2/Dp2
C. Vs2/Dp3
D. Vs/Dp3
