Cyclone Separator Challenge

AIM :- To perform an analysis of the cyclone seperator and calculate the seperation efficiency and pressure drop.

OBJECTIVES :- To finding seperation efficiency at different velocities and partical size in given range.

Given Boundary conditions are :-

For Inlet and Walls -> Reflect

For Outlet_dustbin (i.e. at bottom side) -> Trap

For Outlet (i.e. at top side) -> Escape

NOTE :- It\'s not seperate boundary conditions, it is use at a time for each cases at given boundary.

QUE.1) Write a few words about any four empirical models used for cyclone seperator efficiency.

ANS.:- Cyclone Seperator :-

Cyclone seperator provides a method of removing particulate matter from air or other gas streams at low cost and low maintainance. Cyclones are somewhat more complicated in design than simple gravity settling systems, and their removal efficiency in much better than that of the setting chamber. Cyclones are centrifugal seperator, consists of an uppar cylindrical part reffered to as the barrel and a lower conical part reffered to as cone.

The simply transform the Inertia force of gas particle flows to a centrifugal force using a vertex generated in the cyclone body. The particle ladden air stream enters tangentially at the top of the barrel and travel downword into the cone forming an outer vortex. The increasing air velocity in the outer vortex results in a centrifugal force on the particle seperating them from the air stream. When air reaches the bottom of the cone, it beging to flow radially inward and out the top as clean air/gas while the particulates fall into the dust collection chamber atteched to the bottom of the cyclone.

There are different empirical models used for cyclone seperator efficiency, from which I discuss here four important and applicable empirical models are follows-

1. Lapple model :-

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

The efficiency of collection of any size of the particle is given by-

2. Koch and Licht model :-

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

Koch and Licht describe particle motion in the entry and collection regions by the following-

# Assumptions :-

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

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

3. Li and Wang model :-

The Li and Wang model involve particle bounce or retraining and turbulent diffusion on the wall of the cyclone. A 2-dimensional descriptional of the distribution of particle in the cyclones is obtained.

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

4. Iozia and Leith model :-

Iozia and Leith\'s model is based on forced balance. The model assumes that a particle carried by the vertex endures the influence of two forces centrifugal forces and the flow resistance.

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

QUE.2) Perform an analysis of the given cyclone seperator model by varying the particle diameter from 1 micrometer to 10 micrometer and calculate the seperation efficiency in each case. Discuss the results . [Use both the velocity as 3 m/s]

ANS.:- I consider here total three cases within the range of 1 - 10 micrometer by taking constant velocity at each case which is 3 m/s.

CASE-1 :-

Mesh Element size = 10mm

Total number of element = 111352

Total number of nodes = 22716

Particle diameter = 1e-6 meter

velocity = 3 m/s

BC are-

Inlet & walls -> Reflect

Top outlet -> Escape

Outlet_dustbin -> trap

1. Space claim geometry :-

This is the basis geometry which we get after volume extracting in space claim-> prepare menu. Before volume extracting one things always keep in mind here that, in basic geometry it have thickness and due to thickness it have two layers i.e. inner layer and outer layer, but for the meshing we require to select inner layer and it volume extracted and then save in basic geometry. Also other than geometry suppress for physics and only topology share.

2. Meshing :-

This is the meshing of given geometry. We can choose here any element size but for better result we always provided lower element size. Also one things keep in mind that this is academic license and it have limitation to the number of element so that always provided propar i.e. average element size. If I provided here 5mm element size then it exceed to the academic licence and not will allow further process.

3. DPM at inlet BC :-

This is the DPM boundary conditions, which is already given and we have to select. There have three DPM boundary conditions given and it is among them. It is one of the type of DPM by which particle varried.

4. Momentum at inlet BC :-

This is the momentum boundary conditions, where guage pressure is zero pascal and velocity magnitude is 3 m/s. Also Turbulent viscosity Ratio is 10. The velocity method must be normal to the boundary.

5. DPM at top outlet BC :-

Here shown boundary condition type of DPM is escape at top outlet, because there particles must be escaped in to the atmosphere.

6. DPM at outlet_dustbin BC :-

Here shown Discrete phase BC type at outlet_dustbin is trap.

7. Momentum at top outlet BC :-

This is the pressure outlet zone where guage pressure is zero pascal.

8. Domain Extents :-

This is the domain extent where checking everythings like share topology, meshing, coordinates, volume, area, bounday name and initialize values...etc.

9. Converged Solution with DPM iterations :-

It is the final calculation of solution where converged solution is given, Dpm iterations also given where number of tracked particle, escaped particle, traped particle and incomplete particles are given. Here,

Inlet pressure = 13.727 Pa and Outlet pressure = 8.798 Pa

10. Discrete phase model (i.e. DPM) :-

This is the discrete phase model where choose by default Maximum number of steps, Step length factor and DPM iteration intervals are given by default.

11. General model :-

This is the general model where solver type is Pressure based and velocity formulation is Absolute in steady time condition. Here gravitational acceleration through negative Y-direction because particle moves downword from inlet.

12. Injection proparties :-

This is the injection proparties, where injection type is surface at inlet boundary conditions Also velocity is 3 m/s, particle diameter is 1e-6 and total flow rate is 1e-20, also particle type is Inert.

13. Mass flow at Inlet :-

It is the function calculation of mass flow at inlet boundary conditions. It is the positive value it means mass flow at inside the direction of the cyclone seperator.

14. Mass flow at outlet_dustbin :-

This is the function calculation value of Mass flow on outlet_dustbin boundary conditions. It is the negative value it means mass flow at outside the direction of the cyclone seperator.

15. Mass flow at top_outlet :-

This is the value for mass flow at top outlet of cyclone seperator. It is negative it means mass flow at outside direction of the cyclone seperator.

16. Mass flow at walls :-

At walls there have no value for mass flow.

17. Pressure contours :-

It is the static pressure contour which is minimum value is -5.08 and maximum value is 15.4 pascals.

18. Velocity contours :-

It is the velocity magnitude contours, where minimum velocity = 0 m/s and maximum velocity = 10 m/s.

19. Viscous model :-

It is the viscous model from which k-epsilon model is used in which RNG type and in that Swirl dominated flow near to the standerd wall functions used. Because it is cyclone seperator which is used for pure and impure particle seperations.

20. Solution control :-

It is the solution controls in which select all defaults value.

21. Solution Initialization :-

It is solution initialization where, Standard initialization method is used which compute from Inlet at which relative to cell Zone refference Frame is used. and use all default values.

22. Solution Method :-

It is the solution methods, in pressure velocity coupling Coupled scheme are used in which Turbulent kinetic energy is Second order upwind and Turbulent dissipation rate is Second order upwind used and remainings are default settings are used.

23. Pressure drop at Inlet :-

It is the plot of area weighted average of pressure, calculated for each iterations, where Inlet pressure = 13.727 Pascals.

24. Pressure drop at outlet_dustbin :-

It is the pressure drop value for outlet_dustbin which is zero i.e. constant everywhere.

25. Pressure drop at wall :-

It is the area weighted average of pressure plot, where shown some pressure on the wall.

26. Animation Settings :-

The animation created for fluent at anthrasite particle time, save in specific location in MPEG4 format which repeats only once. The animation quality set as HD 710P in Highest mode where Frame rate is 24. and click on play buttons, video must be essaved.

27. Fluent at anthrasite particle time :-

It is the Fluent at Anthrasite particle time plot. In which minimum value is zero and maximum value is 7.17 seconds. Here shown minimum particle Escape and maximum particle are traping. I enter 124 particle which is maximum number of particle according to mesh size.

28. Fluent at walls :-

a)

b)

Here we can see that fluent at walls, which can be swirl inside the cyclone.

29. Pressure drop at top outlet :-

It is the Area weighted average of pressure drop in top outlet direction which is equal to 8.7864 pascals.

30. Pressure stream :-

This is the pressure streamline for which maximum pressure at inlet. Streamline pressure within the range of -4.306 to 24.92 pascals.

31. Velocity stream :-

Here, velocity streamline within the range of 0 to 5.153 m/s.

32. Vortex core region :-

a)

b)

It is the vortex region in the given range at maximum and minimum limit.

33. Report file :-

It is the report file in which we can see that Total number of nodes, total number of elements and various boundaries which I mentioned.

34. Animation file :-

It is the final animation file, in which we can see that motion of particle from inlet to outlet and we can clearly see that here how much particles are trped, tracked, escaped, evaporated and incomplete.

In this way I Calculated three cases within the particle range of 1e-6 meter to 1e-5 meter. In that cases I calculated and showing differ data and which data are similer to first case I excluded that one. Remaining two cases are given below-

CASE-2 :-

Mesh Element size = 10mm

Total number of elements = 111352

Total number of nodes = 22716

Particle diameter = 5e-6 meter

velocity = 3 m/s

BC are-

Inlet & wall -> Reflect

Top_outlet -> Escape

Outlet_dustbin -> Trap

1. Meshing :-

2. Converged solution with DPM iterations :-

3. Injection Proparties :-

4. Scaled residuals :-

5. Pressure drop at inlet :-

6. Pressure drop at outlet_dustbin :-

7. Pressure drop at top outlet :-

8. Pressure drop at wall :-

9. Mass flow at inlet :-

10. Mass flow at outlet_dustbin :-

11. Mass flow at top outlet :-

12. Report file :-

13. Animation file :-

CASE-3 :-

Mesh Element size = 10mm

Total number of elements = 111352

Total number of nodes = 22716

Particle diameter = 10e-6

Velocity = 3 m/s

BC are-

Inlet & wall -> Reflet

Top_outlet -> Escape

Outlet_dustbin -> Trap

1. Meshing :-

2. Converged solution with DPM iterations :-

3. Injection proparties :-

4. Scaled residuals :-

5. Pressure drop at inlet :-

6. Pressure drop at outlet_dustbin :-

7. Pressure drop at top outlet :-

8. Pressure drop at wall :-

9. Fluent Anthrasite Particle time :-

10.Mass flow at inlet :-

11. Mass flow at outlet dustbin :-

12. Mass flow at top outlet :-

13. Mass flow at wall :-

14. Report file :-

15. Animation file :-

RESULTS :-

Constant velocity = 3 m/s.

As above three cases I changed only particle diameter from 1 micrometer to 10 micrometer and then I concluded following data are-

1. For particle size = 1e-6 meter, Total Number tracked = 124, Escaped = 31, Traped = 41, Incomplete = 52, Number of iterations required to Converged solution = 450, Efficiency range = 40% to 50%.
2. For particle size = 5e-6 meter, Total number tracked = 124, Escaped = 3, Traped = 115, Incomplete = 6, Number of iterations required to Converged solution = 450, Efficiency range = 60% to 70%.
3. For particle size = 10e-6 meter, Total number tracked = 124, Escaped = 00, Traped = 110, Incomplete = 14, Number of iterations required to Converged solution = 450, Efficiency range = 50% to 60%.

For calculating Pressure drop-

Pressure drop = Inlet pressure - Outlet pressure

1. For particle size = 1e-6 meter, Inlet pressure = 13.742 Pa, Outlet pressure = 8.7984 Pa, Pressure drop = 4.6216 Pa.
2. For particle size = 5e-6 meter, Inlet pressure = 13.742 Pa, Outlet pressure = 8.7984 Pa, Pressure drop = 4.6216 Pa.
3. For particle size = 10e-6 meter, Inlet pressure = 13.742 Pa, Outlet pressure = 8.7984 Pa, Pressure drop = 4.6216 Pa

From above we can say that selection of particle diameter gives better results to give traping particles.

QUE.3) Calculate the seperation efficiency and pressure drop by varrying the inlet velocity of both the fluid and particles from 5 m/s to 10 m/s and discuss the results. ( Use the particle diameter size as 5 micrometer). ANS.:- I describe here total three different cases by changing the velocity in the given range and by taking all remaining data are constant. Also I describe here inlet and outlet preesure for calculating pressure drop.

CASE-1 :-

Mesh element size = 10mm

Total number of elements = 111352

Total number of nodes = 22716

Particle diameter = 5e-6 meter

Velocity = 5 m/s

BC are-

Inlet & wall -> reflect

Outlet_dustbin -> Trap

Top_outlet -> Escape

1. Meshing :-

2. Converged solution :-

Here, Inlet pressure = 39.394 Pa and Outlet pressure = 25.524 Pa.

3. DPM Iterations :-

4. Velocity at inlet :-

5. Injection proparties :-

6. Velocity at inlet :-

7. Scaled Residuals :-

8. Pressure drop at inlet :-

9. Pressure drop at outlet_dustbin :-

10. Pressure drop at top_outlet :-

11. Fluent anthrasite particle time :-

12. Mass flow at inlet :-

13. Mass flow at outlet_dustbin :-

14. Mass flow at top_outlet :-

15. Mass flow at wall :-

16. Vortex Region :-

a)

b)

17. Report file :-

18. Animation file :-

CASE-2 :-

Mesh element size =10mm

Total number of elements = 111352

Total number of nodes = 22716

BC are

Inlet & walls -> Reflect

Top_Outlet -> Escape

Outlet Dustbin -> Trap

Diameter of particle = 5e-6 meter

Velocity = 7 m/s

1. Meshing :-

2. Converged solution with DPM iterations :-

Here, Inlet pressure = 78.203 Pa and Outlet pressure = 50.999 Pa.

3. Injection Proparties :-

4. Scaled Residuals :-

5. Pressure drop at inlet :-

6. Pressur drop at outlet_dustbin :-

7. Pressure drop at top_outlet :-

8. Pressure drop at wall :-

9. Mass flow at inlet :-

10. Mass flow at outlet_dustbin :-

11. Mass flow at top_outlet :-

12. Mass flow at wall :-

13. Fluent Anthrasite particle time :-

14. Report file :-

15. Animation file :-

CASE-3 :-

Mesh element size = 10mm

Total Number of elements = 111352

Total number of nodes = 22716

BC are-

Inle & Walls -> Reflect

Top outlet -> Escape

Outlet dustbin -> Trap

Particle diameter = 5e-6 meter

Velocity = 10 m/s

1. Meshing :-

2. Injection Proparties :-

3. Converged solution :-

Here, Inlet pressure = 162.64 Pa and Outlet pressure = 106.77 Pa.

4. Scaled residuals :-

5. Pressure drop at inlet :-

6. Pressure drop at outlet_dustbin :-

7. Pressure drop top_outlet :-

8. Pressure drop at wall :-

9. Fluent anthrasite particle time :-

10. Mass flow at inlet :-

11. Mass flow at outlet dustbin :-

12. Mass flow at top_outlet :-

13. Mass flow at walls :-

14. Report file :-

15. Animation File :-

RESULTS :-

Particle size are constant i.e. 5e-6 meter.

a) From above different three cases I concluded the following assumptions are-

1. For velocity = 5 m/s, Total number tracked = 124, Traped = 106, Incomplete = 18, Number of iterations required to converged solution = 457, Efficiency range = 40% to 50%.
2. For velocity = 7 m/s, Total number tracked = 124, Traped = 122, Incomplete = 02, Number of iterations required to converged solution = 451, Efficiency range = 50% to 60%.
3. For velocity = 10 m/s, Total number tracked = 124, Traped = 124, Incomplete = 00, Number of iterations required to converged solution = 455, Efficiency range = 60% to 70%.

b) To find the pressure drop I use simple formula i.e

Pressure drop = Inlet pressure - Outlet pressure

1. For velocity = 5 m/s, Inlet pressure = 39.394 Pa, Outlet pressure = 25.524 Pa, Pressure drop = 13.87 Pa
2. For velocity = 7 m/s , Inlet pressure = 78.203 Pa, Outlet pressure = 51 Pa, Pressure drop = 27.203 Pa
3. For velocity = 10 m/s, Inlet pressure = 162.64 Pa, Outlet pressure = 106.77 Pa, Pressure drop = 55.87 Pa

CONCLUSIONS :-

From above different cases by changing particle diameter and velocity I concluded following data-

1. For getting propar result for cyclone, meshing size must be correct.
2. For getting propar results for cyclone, particle diameter must be accurate.
3. For getting propar results for cyclone, velocity must be accurate.
4. Injection proparties are must be propar and select well injection type.
5. Solution method must be propar i.e. second order upwind and simple method is used.

Likewise, if we consider propar data then we get more effciency for cyclone seperator.

Also,

1. Pressure at inlet is more than at outlets.
2. Velocity at inlet is less than at outlets.
3. Axial velocity at inlet and bottom outlet is less than top outlet.

Above three cases I discuss with pictorically as follows-

In this way I completed this project by calculating and finding required and important quantities and discuss in results in very broad manner. I calculated everythings by considering different cases in given range and find out which quantity is best for the better results. In this way I successfully completed this projectby plotting, calculating and other pictorical way.