Cylindrical Cyclon Separator-6

Cylindrical Cyclone Separator Tanaka Lab.

Analysis Condition Cf.article

(Akiyama) Analysis Condition

Analysis Program FrontFlow/blue Fluent 15.0 Xflow2014

Time Unsteady Steady/ Unsteady Unsteady

Analysis Model LES

SST k-, LES Standard k- Standard k-

WMLES

Element Number 17,000,000

820,000/ 7,900,000 4,000,000

Element Structure Hexa

Tetra, Hexa Octant tree

Inlet 9.47 [m/s] Re = 4.38104

Outlet 0 [Pa]

Tanaka Kazuhiro Lab 2

Z=0

Tangential Velocity

0.0

1.0

2.0

-0.5 0.0 0.5

u / U

IN

x/D

z/D=-2.43 z/D=-3.57 2.0

0.0

1.0

-0.5

u / U

IN

0.0 0.5

x/D

Exp LES Akiyama SST k- k- k- XFLOW LES(FLUENT)

Comparisons of computed and measured tangential velocity in Z/D=-2.43, -3.57

An analysis result of XFLOW is the closest to experimental value in each model.

SST k-, k-, k- model computed steady-state analysis.

LES (FLUENT) approximately 50% are overestimated in comparison with experimental value.


Axial Velocity

-0.5 w

/ U

IN

0.0

0.5

1.0

-0.5 0.0 0.5

x/D

z/D=-3.57

w /

UIN

-0.5

0.0

0.5

1.0

-0.5 0.0 0.5

x/D

z/D=-2.43

In five models, a tendency of XFLOW make advances in comparison with an experimental data in z/d=-2.43 , z/d=-3.57.

Exp LES Akiyama SST k- k- k- XFLOW LES(FLUENT)

Comparisons of computed and measured axial velocity in Z/D=-2.43, -3.57


Comparison of Tangential Velocity (Steady) u /UIN

0 2.5 x

y

x y

z

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

Flow

A tendency seems similar and can catch a whirlpool core clearly qualitatively.

Cf.article x

y

x

z u /UIN

0 2.5

z/D = -2.43

z/D = -3.57

z/D = -0.335

Computed

LES(FLUENT)


Comparison of Axial Velocity (Steady)

Flow

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

w/UIN

-0.5 1.5 x

y

x

y

x

z

z/D = -2.43

z/D = -3.57

z/D = -0.335

w/UIN

-0.5 1.5

x y

z

A tendency comes closer qualitatively.

Cf.article

LES(FLUENT)

Computed



0 2.5 x

y

x y

z

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

Flow

x

y

x

z u /UIN

0 2.5

z/D = -2.43

z/D = -3.57

z/D = -0.335

The circumferential high-speed flow around the central axis of the spiral whirl core could not be confirmed.

Cf.article Computed

SST k-



Flow

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

w/UIN

-0.5 1.5 x

y

x y

z

x

y

x

z

-0.5 1.5

w/UIN

z/D = -2.43

z/D = -3.57

z/D = -0.335

The flow suddenly damps below at z/D=-2.43, and the high-speed upswing around the central axis could not be confirmed.

Cf.article Computed

SST k-



0 2.5 x

y

x y

z

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

Flow

x

y

x

z u /UIN

0 2.5

The high-speed circumferential flow around the central axis of the spiral whirlpool could not be confirmed.

z/D = -2.43

z/D = -3.57

z/D = -0.335

Standard k-

Computed Cf.article



Flow

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

w/UIN

-0.5 1.5 x

y

x y

z

x

y

x

z

-0.5 1.5

w/UIN


z/D = -2.43

z/D = -3.57

z/D = -0.335

Standard k-

Computed Cf.article



0 2.5 x

y

x y

z

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

Flow

x

y

x

z u /UIN

0 2.5

I cannot confirm the high-speed turning speed of the central axis circumference of the spiral whirlpool.

z/D = -2.43

z/D = -3.57

z/D = -0.335

Standard k-

Computed Cf.article



Flow

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

w/UIN

-0.5 1.5 x

y

x y

z

x

y

x

z

-0.5 1.5

w/UIN


z/D = -2.43

z/D = -3.57

z/D = -0.335

Standard k-

Computed Cf.article


Comparison of Tangential Velocity at t=3.0[s]

The influence through difference of the calculation lattice can be seen, but the circumferential velocity distributions comes closer qualitatively.

LES(XFLOW)

x

y

x y

z

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

Flow

Cf.article u /UIN 0 2.5 x

y

x

z

Computed

z/D = -2.43

z/D = -3.57

z/D = -0.335

0 2.5

u/UIN


Comparison of Axial Velocity at t=3.0[s]

The flow comes closer qualitatively. Because the width of contour cannot be controlled, the comparison is difficult.

x y

z

LES(XFLOW)

Flow

z/D = -2.43

Vortex Table

z/D = -3.57

z/D = -0.335

w/UIN

-0.5 1.5 x

y

x y

z

x

y

x

z

z/D = -2.43

z/D = -3.57

z/D = -0.335

Computed Cf.article -0.5 1.5

w/UIN


Comparison between XFLOW and FLUENT

x

y

x

z

u /UIN

0 2.5

z/D = -2.43

z/D = -3.57

z/D = -0.335

7,900,000element

0 2.5

u/UIN

XFLOW FLUENT 3,900,000 element

Because line-formed distributions are seen in XFLOW, so XFLOW realizes higher precision than FLUENT.


Conclusion

Using each model of the numerical analysis, the comparison between the experimental values, used for the article of Akiyama and the calculated values through XFLOW and FLUENT.

The vortex core of the spiral whirlpool could not arrive at to a vortex table in SST k-, Standard k-, Standard k- model, even the phenomena could be seen in the experiment of Akiyama.

In all calculation models, XFLOW gives the closest results with the experimental value quantitatively.


conclusions

Stairmand Cyclone Separator Tanaka Lab.

Cf. Article

Derksen, J.J., Separation Performance Predictions of a Stairmand High-Efficiency Cyclone, AIChE Journal, Vol. 49, No. 6 (2003), pp. 1359-1371.

0.2D

0.36D 0.51D

0.62D

D = 0.29 [m]

0.14D 1.5D

D 0.5D 0.84D 0.52D

2.5D 2D 4D 1.5D

0.37D D D 0.5D

Inlet Outlet

Swirl Stop

Feed Chamber Vortex Finder Dust Collection Box x

z y

x

z y


Analysis Condition

3.25D

Measurement Location

x

z

y

Cf. article (Derksen) Analysis Condition

Analysis Program - Fluent 15.0 Xflow2014

Time Unsteady Steady/ Unsteady Unsteady

Analysis Model LES

SST k-, LES Standard k- Standard k-

WMLES

Element Number 7,700,000

380,000/ 8,800,000

100,000/ 9,300,000

Element Structure Hexa Hexa Octant tree

Inlet 16.1 [m/s] Re 2.8105

Outlet

= 0 0 [Pa] Tanaka Kazuhiro Lab 19

Tangential Velocity and Axial Velocity

-2

-1

0

1

2

-1 0 1

Location x/R

Velo

city

u/U

in

-0.5

0

0.5

1

-1 0 1

Location x/R Ve

loci

ty u

z/Uin

Steady Viscosity model 3,800,000element(FLUENT)

LES Darksen Exp Hoekstra

SST k-

Realizable k-e

RNG k-e

RSM

Standard k-

LES Darksen Exp Hoekstra

SST k-

Realizable k-e

RNG k-e

RSM

Standard k-

-2

-1

0

1

2

-1 0 1-0.5

0

0.5

1

-1 0 1


The evaluation of tangential velocity near the wall is not appropriate. The distribution of axial velocity is much different at the center of pipe, compared with experimental result.

Tangential Velocity and Axial Velocity Unsteadyt = 0.735 [s] LES 8,800,000 element(FLUENT)

Location x/R

Velo

city

u/U

in

Location x/R

Velo

city

uz/U

in

-2

-1

0

1

2

-1 0 1

LES Darksen Exp Darksen

LES(FLUENT)


LES(FLUENT) XFLOW XFLOW

-0.5

0

0.5

1

-1 0 1

100,000 element(XFLOW)


The gap of the peak values is caused by unsteady flow analysis. The results of XFLOW are instantaneous values.

The difference of axial velocity is caused by strong unsteadiness of the vortex core of the spiral whirlpool.

Tangential Velocity and Axial Velocity Average(Time) (1[s]~3[s]) WMLES 9,300,000element(XFLOW)



0 -2

0.5 -0.5

2

0

x/D

/

Xflow Xflow

0 -0.5

0.5 -0.5

1

0

x/D

w/

0.75D

Measurement location


Both of tangential velocity and axial velocity correspond to experimental result qualitatively. The peak value of tangential velocity is 25% bigger than the experimental result in our evaluation. The peak value of axial velocity is 10% bigger than the experimental result in our evaluation.

The time required in the XFLOW analysis

Analysis Element number time Simulation

time CPU(core) Analysis

Stairmand cyclone 9,300,000 Unsteady 3.0[s] 40(20) 180[h]

Stairmand cyclone 100,000 Unsteady 10.0[s] 8 6[h]

Akiyama cyclone 3,920,000 Unsteady 3[s] 16 140[h]

Stairmand cyclone 8,800,000 Unsteady 5[s] 20 168[h]

Stairmand cyclone 3,800,000 Unsteady 5[s] 20 72[h]

Akiyama cyclone 7,900,000 Unsteady 3[s] 20 168[h]

Unsteady analysis only


XFLO

W

FLUEN

T

Conclusion


The analysis through LES of XFLOW realizes unsteady motion of inside flow correctly.

The results of XFLOW LES shows that the velocity near the wall is different from the experimental results because of influence of boundary condition and calculation lattice.

Even though LES XFLOW result with 9,300,000 element still has a little gap compared with the experiments, but the LES result and peak values agree with the experiments qualitatively.

Conclusions

Cylindrical Cyclone SeparatorAnalysis ConditionTangential VelocityAxial VelocityComparison of Tangential Velocity (Steady)Comparison of Axial Velocity (Steady)Comparison of Tangential Velocity (Steady)Comparison of Axial Velocity (Steady)Comparison of Tangential Velocity (Steady)Comparison of Axial Velocity (Steady)Comparison of Tangential Velocity (Steady)Comparison of Axial Velocity (Steady)Comparison of Tangential Velocity at t=3.0[s]Comparison of Axial Velocity at t=3.0[s]Comparison between XFLOW and FLUENTConclusionStairmand Cyclone SeparatorCf. ArticleAnalysis ConditionTangential Velocity and Axial VelocityTangential Velocity and Axial VelocityTangential Velocity and Axial VelocityThe time required in the XFLOW analysisConclusion

Cylindrical Cyclon Separator-6

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