Home / Examples / Fluid Analysis [Bernoulli] / Example 21: Static Mixer

Example 21: Static Mixer

General

• The mixing process, with a static mixer, in an aqueous solution where water and diffusing materials are dissolved is analyzed.
  

• The fluid flows in with a mole fraction of 0% from the first inlet and a mole fraction of 100% from the second inlet.
   

• The static mixer has a portion, referred to as "Element", inside its pipe. The Element promotes the mixing.
  

• The degree of mixing is compared between with and without the Element.
  

• Unless specified in the list below, the default conditions will be applied.

 

• Obtain this session's project file. (Right-click and choose 'Save link as')

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• Results will vary depending on Femtet version and the PC environment.

 

Analysis Space

Item	Settings
Analysis Space	3D
Model Unit	mm

 

Analysis Conditions

Item	Tab	Settings
Solver	Solver Selection	Fluid Analysis [Bernoulli]
Diffusion Analysis	Fluid Analysis	Select Diffusion Analysis
Diffusion Analysis Setting	Fluid Analysis	Type and Unit of Diffusion Quantity: Mole Fraction   Coefficient of Diffusion 1.0 x 10^-9 [m2/s]
Meshing Setup	Mesh	General Mesh Size: 2.0 [mm]

 

Model

Compare the model that has a portion, referred to as "Element", along the flow path in the pipe and the model that does not.

 

Body Attributes and Materials Setting

Body Number/Type	Body Attribute Name	Material Name
19/Solid	Fluid	100_Water *
23/Solid(with the Element)	Pipe_and_Element	001_Al *
22/Solid(without the Element)	Pipe	001_Al *

* Available from the material DB

Boundary Condition

Boundary Condition Name/Topology	Tab	Boundary Condition Type	Settings
Inlet_0/Face	Fluid	Inlet	Forced Inflow Flow Velocity: 1 [m/s] Diffusion Analysis Setting Select Use Ambient Value.
Inlet_0/Face	Fluid	Inlet	Forced Inflow Flow Velocity: 1 [m/s] Diffusion Analysis Setting Select [Direct Entry]. Mole Fraction: 100[%]
Outlet/Face	Fluid	Outlet/Outlet	Natural Inflow/ Natural Outflow

 

Results

The mole fraction of diffusing materials and the streamlines are displayed below.

For the model with the Element, the fluids having high mole fraction and low fraction, respectively, swirl along the Element.

 

With the Element	Without the Element

 

 

The distribution of mole fraction at the outlet is displayed.

The mole fractions are in the range of 31 to 69% without the Element and 42 to 60% with the Element. This indicates the Element enhances the mixing.

 

With the Element	Without the Element