Week 8 - Simulating Cyclone separator with Discrete Phase Modelling

Aim

To perform analysis on cyclone separator and calculate the separation efficiency and pressure drop.

Objective:-

1. To write a few words about any four empirical models used to calculate the cyclone separator efficiency.
2. To perform an analysis on a given cyclone separator model by varying the particle diameter from 1 μm to 5 μm and calculate the separation efficiency in each case. Discuss the results. [Use both the velocity's as 3m/sec.]
3. To perform an analysis on a given cyclone separator model by varying the particle velocity from 1 m/sec to 5 m/sec and calculate the separation efficiency and pressure drop in each case. Discuss the results. [Use particle diameter size as 5 μm for all cases & keep flow velocity same as particle velocity]

Theory

Cyclone separators work much like a centrifuge, but with a continuous feed of dirty air. In a cyclone separator, dirty flue gas is fed into a chamber. The inside of the chamber creates a spiral vortex, similar to a tornado. This spiral formation and the separation is shown in Figure 2. The lighter components of this gas have less inertia, so it is easier for them to be influenced by the vortex and travel up it. Contrarily, larger components of particulate matter have more inertia and are not as easily influenced by the vortex.

Pre-processing and solver setting

Gemotery

mesh

traget length = 6.0 mm

Name selection

Boundary Conditions:-

Inlet and wall:- Reflect

Outlet(Top):- Escape

Outlet(Bottom/dustbin) - Trap

Fluent Setup:

Solver: Steady State solver

Type: Pressure based

Model: k-epsilon RNG, Swril dominated flow, Standard wall function

Injections:

Type - Surface injection

Material type - Antracite

X-velocity - 3m/s

Diameter - varying from 1e-6 to 5e-6

Flow rate - 1e-20 kg/s

case -1

partical diameter = 1e-6

contour plot

velocity contour

pressure contour

partical diameter = 2e-6

partical diameter = 3e-6

contour plot

partical diameter = 4e-6

partical diameter = 5e-6

pessure contour

velocity contour

seperation efficiency = number of patical trapped / number of partical tracked

No	particla diameter	partical velocity	flow velocity	number of particla tracked	number of partical escaped	number of the partical trapped	separtion of effeciency
1	1e-6	3 m/s	3 m/s	378	33	271	71
2	2e-6	3 m/s	3 m/s	378	27	305	80
3	3e-6	3 m/s	3 m/s	378	72	306	79
4	4e-6	3 m/s	3 m/s	378	87	291	75
5	5e-6	3 m/s	3 m/s	387	25	247	63

case -2

partical velocity 1m/s to 5m/s

partical velocity = 1 m/s

residual

pressure contour

velocity contour

partical velocity =2

residual

pressure contour

velocity contour

partical velocity =3

residual

pressure contour

velocity contour

particla velocity =4

residual

pressure contour

velocity contour

No	particla diameter	partical velocity	flow velocity	number of particla tracked	number of partical escaped	number of the partical trapped	separtion of effeciency
1	5e-6	1 m/s	1 m/s	136	12	124	91
2	5e-6	2 m/s	2 m/s	136	21	114	83
3	5e-6	3 m/s	3 m/s	136	41	95	69
4	5e-6	4 m/s	4 m/s	378	127	251	66
5	5e-6	5 m/s	5 m/s	387	74	281	72

Result

When the diameter of the particle varies from 1 μm to 5μm by keeping the flow velocity constant of 3m/s the separation efficiency increases .As the velocity of the particle varies from 1m/s to 5m/s by keeping the particle diameter constant of 5μm the separation efficiency increases. Increasing the velocity of particle causes high pressure drop.