CYCLONE SEPERATOR SIMULATION
Cyclone seperator simulation
1.four empirical model used for cyclone seperator efficiency:
1)LAPPLE MODEL
2)KOCH AND LICHT MODEL
3)LI AND WANG MODEL
4)IOZIA AND LEITH MODEL
1)LAPPLE MODEL:
Lapple (1951) model was developed based on force balance without considering the flow resistance. Lapple assumed that a particle entering the cyclone is evenly distributed across the inlet opening. The particle that travels from inlet half-width to the wall in the cyclone is collected with 50% efficiency.
2)KOCH AND LICHT MODEL:
Koch and Licht (1977) collection theory recognized the inherently turbulent nature of cyclones and the distribution of gas residence times within the cyclone. Koch and Licht
describe particle motion in the entry and collection regions with the additional following assumptions:
- 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 uR^n`= constant.
3)LI AND WANG MODEL:
The Li and Wang (1989) model include particle bounce or re-entrainment and turbulent diffusion at the cyclone wall. A two-dimensional analytical expression of particle distribution
in the cyclone is obtained.
4)IOZIA AND LEITH MODEL:
Iozia and Leith (1990) logistic model is a modified version of Barth (1956) model which is developed based on force balance. The model assumes that a particle carried by the vortex endures the influence of two forces: a centrifugal force and a flow resistance.
2.Cyclone seperator simulation:
In this project,CFD simulation of cyclone seperator is carried out using ANSYS Workbench.
Geometry of cyclone seperator is imported in spaceclaim as shown in figure 1.and then after editing model is meshed in Ansys mesher as shown in figure 2 with element size 10 mm.
figure:1 figure 2
after meshing,simulation is done for four boundary condition using Ansys Fluent.
Case 1:
Viscous model:RNG K-Epsilon
Discrete Phase model is used and Anthracite particle is injected.
Boundary condition:
Inlet velocity= 3 m/s
Discrete phase BC type:Reflect
steady state simulation is done,after 600 iteration result is obtained given below.
figure 3
figure 4
figure 5
Case 2:
Discrete phase BC type:trap
Viscous model:RNG K-Epsilon
Discrete Phase model is used and Anthracite particle is injected.
Boundary condition:
Inlet velocity= 3 m/s
steady state simulation is done,after 600 iteration result is obtained given below.
figure 6
figure 7
figure 8
Case 3:
Discrete phase BC type:Escap
Viscous model:RNG K-Epsilon
Discrete Phase model is used and Anthracite particle is injected.
Boundary condition:
Inlet velocity= 3 m/s
steady state simulation is done,after 500 iteration result is obtained given below.
figure 9
figure 10
figure 11
Case 4:
Discrete phase BC type:Wall jet
Viscous model:RNG K-Epsilon
Discrete Phase model is used and Anthracite particle is injected.
Boundary condition:
Inlet velocity= 3 m/s
steady state simulation is done,after 600 iteration result is obtained given below.
figure 12
figure 13
figure 14
3.Simulation for 3 cases:
CASE:1
dia:3e-06
DPM Iteration ....
number tracked = 364
escaped = 306
aborted = 0
trapped = 0
evaporated = 0
incomplete = 58
CASE 2:
dia:2e-06
DPM Iteration ....
number tracked = 364
escaped = 317
aborted = 0,
trapped = 0,
evaporated = 0
incomplete = 47
CASE 3:
dia:0.5e-06
DPM Iteration ....
number tracked = 364
escaped = 303
aborted = 0
trapped = 0
evaporated = 0
incomplete = 61