solve it---Q1.
Air is moving upward in a bed packed with spherical glass particles of diameter 240 micron in a glass column (open to atmosphere) whose inner diameter is 4.4 cm and length is 0.38 m. The depth of the packed bed is 0.1 m. The mass of the particles in the column is 0.232 kg.
The density of the glass particles is 2500 kg/m³.
Density of air = 1.2 kg/m³.
Viscosity of air = 1.8×10⁻⁵ Pa·s.
At minimum fluidisation, the voidage of the particle bed is 10% higher than that of the packed bed.
Answer the following questions:
a) What is the depth of the bed at minimum fluidisation?
b) Find the minimum superficial velocity of air (U_mf) for fluidisation.
c) Find the maximum superficial velocity of air for fluidisation while keeping ALL the particles within the column.
d) What is the minimum velocity of air at which the particles will be elutriated from the column?
What will be the pressure drop at or above this velocity?
e) Plot (on one chart) the pressure loss and bed depth versus superficial velocity of air (ranging from 0 to 1 m/s). As a rough guide, plot 10 data points that are evenly spaced along each curve. Compare the above chart with what you observed in Lab Prac 2 and use one or two sentences to describe your finding.
f) Estimate the diameter of the bubbles in the fluidised bed when the superficial velocity of air is 0.5 m/s.