FLOW THROUGH FLUIDIZED BED

Aim of the experiment:

To conduct an experiment on the flow of water through fluidized bed and to obtain the effect of

superficial velocity on bed porosity and pressure drop. Determine the minimum fluidization

velocity from the experimental data.

Apparatus Required:- CCl4 Manometer, Hg Manometer, bucket, Stop watch.

Procedure :-

1. Keep the bypass valve open and the main valve closed. Switch on the pump.

2. Connect CCl4 manometer across the bed

3. Allow the fluid through flow through the bed by opening the main valve.

4. Ensure for steady flow condition note down the flow rate using the rotameter .

5. The corresponding height of the bed and the difference in levels in the manometer limbs

to be noted down.

6. The procedure is to be repeated for different flowrates, both for static and fluidized bed

conditions.

7. Use Hg manometer for higher flow rates

8. Collect the the fluid present in the static bed after closing the main valve, to calculate the

void volume.

Data:-

Column Diameter = D = cm

Height of static bed = Lmf =

Viscosity of fluid = µ = cp

Density of fluid = Kg/m3

Density of CCl4 = Kg/m3

Density of Hg = Kg/m3

Packing type =

Density of packing material= ρp = Kg/m3

Φs = Sphericity =

Specific surface area of packing = S = umeUnitbedvol

aSurfaceare

m

m

3

2

Observations:-

Volume of voids = m3

Sl.

No.

Manometer

Reading

ΔHm =

Height

of bed

(L)

cm

Rotameterreading Volumetric

flow rate

m3/s

Calculations :-

Minimum bed porosity = εmf = dVolumeofBe

Voidvolume

Volume of Bed = mfLxD

4

2

Superficial velocity = A

QVo m/s.

Cross sectional area of the tube, A = 4

2D

HmxHw m

= m H2O

ρm = density of manometric fluid

ΔP = ∆Hw.ρ.g = N/m2

Bed Porosity = ε = mf

mf

L

L 11

Sl.

No.

Bed Height

L, cm

Volumetric

flow rate

Q, m3/s

Superficial

Velocity

0v , m/s

∆Hw

m . H2O

Porosity

ε

Pressure

Drop

ΔP

Plot ΔP vs 0v on a log-log graph

Plot ε vs 0v on a log-log graph.

Determine minimum fluidization velocity (Vmf) from both the plots.

ε

vo

Vmf

ΔP

vo

Vmf

Theoretical value of minimum fluidization velocity:-

Determine pressure drop per unit bed height under minimum fluidization condition

mfp

mf

B gL

P

1 = N/m

2/m

Ergun’s equation:

75.1

.

1150

1..

3

2

DpVV

D

L

P

mf

mf

mf

mf

mf

p

mf

B (1)

Solve equation 1 and determine Vmf.

Results :- Report the values of minimum fluidization velocity obtained from plots and from

Ergun’s equation. Comment on effect of superficial velocity on ΔP and ε.