Fluidization Engineering

Minimum Fluidizing Velocity

Question 1
Marks : +2 | -2
Pass Ratio : 50%
On comparison with Fluidized bed and Packed bed, which has the highest voidage?
Fluidized bed
Packed bed
Pressure drop
All of the mentioned
Explanation:
Fluidized bed has little larger voids compared to packed bed.
Question 2
Marks : +2 | -2
Pass Ratio : 50%
What is the range of Reynolds number(Re) for small particles in the fluidization bed?
Re < 20
Re > 20
Re > 1000
20 > Re < 1000
Explanation:
Since larger particles require large velocity of gas to lift the particles, hence the Re is large.
Question 3
Marks : +2 | -2
Pass Ratio : 50%
What is the sphericity of round sand particles?
0.67
0.86
0.63
0.58
Explanation:
Based on the data from the Voidage table at Minimum fluidizing conditions.
Question 4
Marks : +2 | -2
Pass Ratio : 50%
What is the sphericity of Fisher-catalyst particles?
0.67
0.86
0.63
0.58
Explanation:
Based on the data from the Voidage table at Minimum fluidizing conditions.
Question 5
Marks : +2 | -2
Pass Ratio : 50%
Fluidization expression is compared with which equation from fluid mechanics?
Euler’s equation
Bernoulli’s equation
Buoyancy equation
Navier–Stokes equation
Explanation:
Because the Euler’s equation is analogous to Fluidization equation.
Question 6
Marks : +2 | -2
Pass Ratio : 50%
Minimum Fluidizing equation can be expressed in terms of which physical quantity?
Pressure drop
Temperature
Velocity
Volume
Explanation:
Since pressure drop is required to find the exact velocity of gas required to keep the particles floating.
Question 7
Marks : +2 | -2
Pass Ratio : 50%
Fluidization occurs when: Drag force by the upward moving gas ________
Weight of the particle
Weight of the fluid
Volume of the bed
Pressure drop across bed
Explanation:
Drag force by the upward moving gas = Weight of the particle.
Question 8
Marks : +2 | -2
Pass Ratio : 50%
What is the sphericity of anthracite coal particles?
0.67
0.86
0.63
0.58
Explanation:
Based on the data from the Voidage table at Minimum fluidizing conditions.
Question 9
Marks : +2 | -2
Pass Ratio : 50%
What is the sphericity of sharp sand particles?
0.67
0.86
0.63
0.58
Explanation:
Based on the data from the Voidage table at Minimum fluidizing conditions.
Question 10
Marks : +2 | -2
Pass Ratio : 50%
What is the range of Reynolds number(Re) for small particles in the fluidization bed?
Re < 20
Re > 20
20 < Re > 1000
20 > Re < 1000
Explanation:
Since smaller particles require less velocity of gas to lift the particles, hence the Re is low.