COMSOL 6.4 - Turbulent Modular Mixer — Template File

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Turbulent Modular Mixer — Template File

This model is a template MPH file used by the turbulent cases (k-ε and k-ω turbulence models) of the Modular Mixer models. The geometry is a combination of a pitched blade impeller and a dished bottom tank. The geometry subsequences to build the impeller and vessel are imported from the Part Libraries.

Mixer_Module/Tutorials/modular_mixer_turbulent_geom

Modeling Instructions

In the toolbar, click

and choose .

Global Definitions

1

In the window, under click .

2

In the window for , locate the section.

3

In the table, enter the following settings:


Name	Expression	Value	Description
H	0.5[m]	0.5 m	Vessel height
T	H	0.5 m	Vessel diameter
alpha	45[deg]	0.7854 rad	Pitch angle
N_blades	4	4	Number of blades for pitched blade impeller
B	4	4	Number of baffles
Da	1/2*T	0.25 m	Impeller diameter
blade_width	Da/5	0.05 m	Width of impeller blade
bw	T/12	0.041667 m	Baffle width
C	1/4*H	0.125 m	Clearance
shaft_diameter	1/10*Da	0.025 m	Shaft diameter

1

In the toolbar, click

.

2

In the window, under click .

3

In the window, select > > > in the tree.

4

Pitched Blade Impeller 1 (pi1)

1

In the window, under > click .

2

In the window for , locate the section.

3

In the table, enter the following settings:


Name	Expression	Value	Description
d_hu	blade_widthabs(cos(alpha))1.1	0.038891 m	Diameter of impeller hub
ap_ib	alpha	45 °	Pitch angle of the impeller blade
d_a_ib	blade_widthcos(alpha)0.95	0.033588 m	Diameter of the attachment section of the impeller blade with the hub
lr_cl_ib	0.3[1]	0.3	Position of the cutting point relative to the total blade length at the lower edge of the impeller
lr_cu_ib	0.3[1]	0.3	Position of the cutting point relative to the total blade length at the upper edge of the impeller
n_ib	N_blades	4	Number of impeller blades
rf_ib	0[m]	0 m	Fillet radius of impeller blade
w_ib	blade_width	0.05 m	Width of the impeller blade
w_a_ib	0[m]	0 m	Blade attachment width
w_o_ib	blade_width	0.05 m	Outer width of the impeller blade
w_cil_ib	blade_width*0.25	0.0125 m	Width of inner-lower cut
w_ciu_ib	blade_width*0.25	0.0125 m	Width of inner-upper cut
w_col_ib	0[m]	0 m	Width of outer-lower cut
d_im	Da	0.25 m	Impeller diameter
hp_im	-blade_width*sin(alpha)/2	-0.01768 m	Position of the lowest part of the impeller hub or impeller shaft along the z-axis
d_is	shaft_diameter	0.025 m	Diameter of impeller shaft
pa_cs_im	1	1	Add cross-section planes for flow evaluation above and below the impeller: 1 = add planes, 0 = do not add planes.
d_cs_im	Da*1.2	0.3 m	Diameter of cross-section planes above and below the impeller. The planes are used to compute power draw and flow numbers.

4

Click to expand the section. Click .

5

In the dialog, type Impeller Domains in the text field.

6

7

In the window for , locate the section.

8

9

In the dialog, type Control Domain in the text field.

10

11

In the table, enter the following settings:


Name	Contribute to
Impeller	Impeller Domains
Tank	Control Domain

12

In the window for , click to expand the section.

13

14

In the dialog, type Rotating Interior Wall in the text field.

15

16

In the window for , locate the section.

17

18

In the dialog, type Rotating Wall in the text field.

19

20

In the window for , locate the section.

21

22

In the dialog, type View Suppression in the text field.

23

24

In the window for , locate the section.

25

26

In the dialog, type Mesh in the text field.

27

28

In the table, enter the following settings:


Name	Contribute to
Impeller blades	Rotating Interior Wall
Impeller hub	Rotating Wall
Control surface upper	Mesh
Control surface lower	Mesh
Control surface side	Mesh
Surfaces to hide	View Suppression

29

In the window for , click to expand the section.

30

31

In the dialog, type Remove Edges in the text field.

32

33

In the table, enter the following settings:


Name	Contribute to
Edges to remove	Remove Edges

34

In the window for , locate the section.

35

Select the checkbox.

1

In the toolbar, click

.

2

In the window, click .

3

In the window, select > > in the tree.

4

Impeller Shaft 1 (pi2)

1

In the window, under > click .

2

In the window for , locate the section.

3

In the table, enter the following settings:


Name	Expression	Value	Description
hp_im	-blade_width*sin(alpha)/2	-0.017678 m	Position of the lowest part of the impeller hub or impeller shaft along the z-axis
d_is	shaft_diameter	0.025 m	Impeller shaft diameter
l_is	H-C	0.375 m	Impeller shaft length

4

Click to expand the section. In the table, enter the following settings:


Name	Contribute to
Impeller	Impeller Domains

5

Click to expand the section. In the table, enter the following settings:


Name	Contribute to
Exterior	None
Impeller	Rotating Wall

6

Click to expand the section. In the table, enter the following settings:


Name	Contribute to
Edges to remove	Remove Edges
Impeller	None

7

Locate the section. Select the checkbox.

1

In the toolbar, click

.

2

In the window, click .

3

In the window, select > > in the tree.

4

Dished Bottom Tank 1 (pi3)

1

In the window, under > click .

2

In the window for , locate the section.

3

In the table, enter the following settings:


Name	Expression	Value	Description
n_ba	B	4	Number of baffles
w_ba	bw	0.041667 m	Baffle width
d_im	Da	0.25 m	Impeller diameter
d_ta	T	0.5 m	Tank diameter
h_ta	H	0.5 m	Tank height
hp_ta	-C	-0.125 m	Height position, cylindrical surface
rm_b_ta	T/10	0.05 m	Minor radius of the tank bottom
bo_rd_ta	T*2	1 m	Bottom offset of rotating domain relative to the tank bottom minor radius
t_ta	0	0 m	Thickness of tank wall
t_ba	0	0 m	Thickness of tank baffles

4

Locate the section. Click .

5

In the dialog, type Interior Wall in the text field.

6

7

In the window for , locate the section.

8

9

In the dialog, type Symmetry in the text field.

10

11

In the table, enter the following settings:


Name	Contribute to
All	Control Domain

12

Click to expand the section. In the table, enter the following settings:


Name	Contribute to
Baffles	Interior Wall
Fluid surface	Symmetry
Surfaces to hide	View suppression

13

In the window for , locate the section.

14

Select the checkbox to keep all selections from the part.

Rotating Fluid Domain

1

In the toolbar, click

and choose .

2

In the window for , type Rotating Fluid Domain in the text field.

3

Locate the section. From the list, choose .

4

From the list, choose .

5

From the list, choose .

6

Locate the section. Select the checkbox.

7

From the list, choose .

8

Reduce the domain to a quarter of the original size.

1

In the toolbar, click

.

2

In the window for , locate the section.

3

In the text field, type 0.2.

4

In the text field, type -0.2.

5

In the text field, type -0.5.

6

Locate the section. In the text field, type 45.

1

Right-click and choose .

2

In the window for , locate the section.

3

In the text field, type -0.2.

Difference 2 (dif2)

1

In the toolbar, click

and choose .

2

Select the object only.

3

In the window for , locate the section.

4

Click to select the

toggle button for .

5

Select the objects and only.

Flat Pressure Point

1

In the toolbar, click

and choose .

2

In the window for , type Flat Pressure Point in the text field.

3

Locate the section. From the list, choose .

4

On the object , select Point 19 only.

5

In the window, click .

6

Locate the section. Find the subsection. Click .

7

In the dialog, type Pressure Point Constraint in the text field.

8

Form Union (fin)

1

In the window, under > click .

2

In the window for , locate the section.

3

From the list, choose .

4

Clear the checkbox.

5

From the list, choose .

Ignore Edges 1 (ige1)

1

In the toolbar, click

and choose .

2

In the window for , locate the section.

3

From the list, choose .

Mesh Control Faces 1 (mcf1)

1

In the toolbar, click

and choose .

2

In the window for , locate the section.

3

Click to select the

toggle button for .

4

From the list, choose .

5

In the toolbar, click

.

Union Selection: All Walls

1

In the toolbar, click

and choose .

2

In the window for , type Union Selection: All Walls in the text field.

3

Locate the section. From the list, choose .

4

Locate the section. Click

.

5

In the dialog, in the list, choose , , , and .

6

The model geometry is now complete.