Week 8 - Simulating Cyclone separator with Discrete Phase Modelling

A cyclone separator is also called as cyclonic dust collector, is an air pollution control device that cleanses flue gases of particulate matter before such gases exit into the atmosphere.

As the gas enters the separator it undergoes spiral motion. But heavier particles can't change their direction as quickly as gas. These heavier particles collides with the surface and comes down through the reject hole at the bottom.

Discrete phase model (DPM) is used when to study the behavior of the particles from a Lagrangian view. Lagrangian view is examined on the basis of a particle tracking of a particle of fluid flow. Lagrangian approach takes into consideration individual particles and calculates the trajectory of each particle separately, whereas the Eulerian approach deals with concentration of particles and calculates the overall diffusion and convection of a number of particles.

EVALUATION ON EMPIRICAL MODELS FOR THE PREDICTION OF CYCLONE EFFICIENCY

http://dspace.unimap.edu.my/xmlui/bitstream/handle/123456789/13571/054-058_empirical%20models.pdf?sequence=1#:~:text=An%20inaccuracy%20in%20cyclone%20efficiency,inefficient%20design%20of%20cyclone%20separators.&text=This%20study%20reviews%20the%20prediction,Iozia%20and%20Leith%20%5B4%5D.

• IOZIA AND LEITH MODEL
• LI AND WANG MODEL
• KOCH AND LICHT MODEL
• LAPPLE MODEL

Solver settings:

Viscous model: RNG

RNG gives improved predictions for swirl flows.

Enable swirl dominated flow

Enable 'interation with continous phase'

particle size: 5 micrometer

We dont want particles to escape through velocity inlet. So enable reflect

Animation: https://youtu.be/NiBDZ_zc2qU

Particle size: 4 micrometer

Animation: https://youtu.be/LWOKMjjbwrY

= 331/378

= 0.87

Particle size: 3 micrometer

Animation: https://youtu.be/EpdkAUaSzGo

= 299/378

= 0.79

Area Average of Pressure on inlet = 19.5388 [Pa]

Area Average of Pressure on outlet_1 = 0.0147318 [Pa]

Pressure drop: 19.5 Pa

Particle size: 2 micrometer

Anthracite particle time contour shows - time with repect to particle injection.

= 191/378

= 0.505

Animation: https://youtu.be/d5EQEIASyGs

Velocity: 4m/sec

Particle size: 5 micrometer

= 346/378

= 0.91

Area Average of Pressure on inlet = 35.7414 [Pa]

Pressure drop: 35.74 Pa

Animation: https://youtu.be/CwXdUhkZ8LI

Velocity: 5m/sec

Particle size: 5 micrometer

Pressure drop = Outlet - inlet

= 58 Pa

Animation: https://youtu.be/5dEGly2Uw_k

Conclusion:

Increasing the particle size makes the cyclone separator to capture more particles. This increases the efficiency of the separator.

When velocity increases pressure drop increases and efficiency increases.