Cyclone Separator Challenge

Objective:-

We have to perform an analysis on the cyclone seperator model for different number of inectioned particles.

1. The four imperical models used for cuclone seperator efficiency:-

CYCLONE SEPERATOR:-

Cyclone seperators provides a method of removing the particulate matter from air or other gas streams at low costs and low maintenance. Cyclone are somewhat more complicated in design than simple gravity settling systems, and their removal efficiency is much better than that of the settling chamber. Cyclones are centrifugal seperators, consists of an upper cylinderical part reffered to as the barrel,and a lower conical part known as cone.

They simply transform the inertia force of gas particle flows to a centrifugal force using a vortex generated in the cyclone body. The particle-laden air streams enters tangential at the top of the barrel and travels downwards into the cone forming an outer vortex. The increasing air velocity in the outer vortex results in a centrifugal force on the particles seperating them from the air stream. When the air reaches the bottom of the cone it begins to flow radially inwards and out the top as clean air or gas while the particulates fall into the dust collection chamber attached to the bottom of the cyclone.

The four imperical models used for cuclone seperator efficiency-

1. Lapple model

2. Koch and Licht model

3. Li and Wang model

4. Lozia and leith model

1. Lapple model:-

The Lapple model was developed based on the balance of the force without taking into account the flow resistance. Lapple believed that a particle entering the cyclone is spread through the opening of the inlet. The particles moving from the half width inlet to the cyclone walls are collected with an efficiency of 50 percent.

The Efficiency of collection of any size of particle is given by:-

`eta_i=1/(1+(d_\"pc\"/bard_\"pi\")^2)`

2. KochandLicht model:-

Koch and Licht model collection theory reconized the inherently turbulent nature of the cyclone and the distribution of gas residence times within the cyclone.

Koch and Licht described the particles motion in the entry and collection regions by the following assumption-

The tangential velocity of a particle is equal to the tangential velocity of the gas flow, i.e there is no slip in the tangential direction between the particle and the gas.

The tangential velocity is related to the radius of cyclone by u Rn= constant.

A force balance and an equation on the particles collection yields the grade Efficiency

`eta_i=1-exp{-2[(G*tau_i*Q)/D^3]^(0.5/(n+1))}`

3. Li and Wang model :-

The Li and Wang model involve particle bounce or retraining and turbulent diffusion on the wall of cyclone. A two Dimentional description of the distribution of particles in the cyclone is obtained.

The result expression of the collection efficiency for a particle of any size is given as-

`eta_i=1-exp{-lambda*theta_1}`

4. Lozia and leith model :-

Lozia and leith\'s logistic model is based on force balance. The model assumes that a particle carried by the vortex endures the influence of two forces, Centrifugal force and flow resistance force.

The collections Efficiency `eta_i`of particle diameter `d_\"pi\"` can be calculated from

`eta_i=1/(1+(d_\"pc\"/d_\"pi\")^beta)`

Beta is an expression for slope parameter derived based on the statistical of experimental data of a cyclone.

2. Perform an analysis on the given cyclone seperator model and apply four diffferent boundary condition types at the inlet i.e. reflect, trap, escape, wall jet and submit images on your findings on the different conditions.

Escape:-

1. Meshing :-

The base mesh size is 10mm and there are about 364 cells at the inlet which means the same number of particles will be simulated.

2. Scaled residuals:-

The simulation residuals plot is seen to be constant.

3. Velocity contours anthracite particle time:-

The contours of the particle that are in the vortex region inside the cyclone seperator.

4. The contours of vortex:-

The contours of vortex that is created due to the particle velocity and the design of the cyclone seperator.

5. DPM iteration results:-

This is the main data that reveals how many particles are tracked, escaped and incomplete. Escaped particles either escaped the bottom or top outlet.

Reflect:-

1. Meshing :-

The base mesh size is 10mm and there are about 364 cells at the inlet which means the same number of particles will be simulated.

2. Scaled residuals:-

The simulation residuals plot is seen to be constant.

3. Velocity contours anthracite particle time:-

The contours of the particle that are in the vortex region inside the cyclone seperator.

4. The contours of vortex:-

The contours of vortex that is created due to the particle velocity and the design of the cyclone seperator.

5. DPM iteration results:-

This is the main data that reveals how many particles are tracked, escaped and incomplete. Escaped particles either escaped the bottom or top outlet.

Trap:-

1. Meshing :-

The base mesh size is 10mm and there are about 364 cells at the inlet which means the same number of particles will be simulated.

2. Scaled residuals:-

The simulation residuals plot is seen to be constant.

3. Velocity contours anthracite particle time:-

The contours of the particle that are in the vortex region inside the cyclone seperator.

4. The contours of vortex:-

The contours of vortex that is created due to the particle velocity and the design of the cyclone seperator.

5. DPM iteration results:-

This is the main data that reveals how many particles are tracked, escaped and incomplete. Escaped particles either escaped the bottom or top outlet.

Wall-jet:-

1. Meshing :-

The base mesh size is 10mm and there are about 364 cells at the inlet which means the same number of particles will be simulated.

2. Scaled residuals:-

The simulation residuals plot is seen to be constant.

3. Velocity contours anthracite particle time:-

The contours of the particle that are in the vortex region inside the cyclone seperator.

4. The contours of vortex:-

The contours of vortex that is created due to the particle velocity and the design of the cyclone seperator.

5. DPM iteration results:-

This is the main data that reveals how many particles are tracked, escaped and incomplete. Escaped particles either escaped the bottom or top outlet.

Applying four different boundary condition types at the inlet i.e. Reflect, Trap, Escape, Wall-jet but the DPM iterations are same in all the cases.

DPM Iteration	Reflect	Trap	Escape	Wall-jet
Number Tracked	364	364	364	364
Escaped	246	246	246	246
Aborted	0	0	0	0
Trapped	0	0	0	0
Evaporated	0	0	0	0
Incomplete	118	118	118	118
Incomplete-parallel	0	0	0	0

3. Vary the nuber of particle through the inlet and simulate the three cases. Report the number of particles that pass through or remain in the cyclone seperator. For this question use the reflect option as the boundary condition for the discrete phase.

CASE1:-

1. Meshing :-

The base mesh size is 10mm and there are about 364 cells at the inlet which means the same number of particles will be simulated.

2. Scaled residuals:-

The simulation residuals plot is seen to be constant.

3. Velocity contours anthracite particle time:-

The contours of the particle that are in the vortex region inside the cyclone seperator.

4. The contours of vortex:-

The contours of vortex that is created due to the particle velocity and the design of the cyclone seperator.

5. DPM iteration results:-

This is the main data that reveals how many particles are tracked, escaped and incomplete. Escaped particles either escaped the bottom or top outlet.

Animation:-

CASE2:-

1. Meshing with 8mm element size:-

The base mesh size is 8mm and there are about 498 cells at the inlet which means the same number of particles will be simulated.

2. Scaled residuals:-

The simulation residuals plot is seen to be constant.

3. Velocity contours anthracite particle time:-

The contours of the particle that are in the vortex region inside the cyclone seperator.

4. The contours of vortex:-

The contours of vortex that is created due to the particle velocity and the design of the cyclone seperator.

5. DPM iteration results:-

This is the main data that reveals how many particles are tracked, escaped and incomplete. Escaped particles either escaped the bottom or top outlet.

Animation:-

CASE3:-

1. Meshing :-

The base mesh size is 5mm and there are about 1298 cells at the inlet which means the same number of particles will be simulated.

2. Scaled residuals:-

The simulation residuals plot is seen to be constant.

3. Velocity contours anthracite particle time:-

The contours of the particle that are in the vortex region inside the cyclone seperator.

4. The contours of vortex:-

The contours of vortex that is created due to the particle velocity and the design of the cyclone seperator.

5. DPM iteration results:-

This is the main data that reveals how many particles are tracked, escaped and incomplete. Escaped particles either escaped the bottom or top outlet.

Conclusion:-

1. The discrete phase boundary condition type has an effect on the tracing of the particle.

2. Mesh size has a prominent effect on the scaled residuals as well as the tracing of the particles.

3. Due to poor mesh or coarse mesh many particles in the vortex were untraced and declared as incomplete.

4. A small number of partcles escaped from the top outlet.

5. Gravity has a huge impact on the particles since most of the particles escaped from the bottom outlet.

The following table shows that as we refine the mesh size the number of input particles increased and the number of tracked also increases.

Mesh element size	10 mm	8 mm	5mm
Number tracked	364	498	1298
Escaped	246	442	616
Aborted	0	0	0
Trapped	0	0	0
Evaporated	0	0	0
Incomplete	118	56	682
Incomplete-parallel	0	0	0