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PhD Student: Cristopher Morales Ubal, Power&Flow Group, TU Eindhoven.

Supervisors: Prof. Dr. Jeroen Van Oijen, Power&Flow Group, TU Eindhoven.

                      Dr.Ir. Nijso Beishuizen, Bosch Thermotechnology , TU Eindhoven.

Department of Mechanical Engineering, Power & Flow Group

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Motivation

  • Motivation: Optimizing mixing devices where two goals can be achieved simultaneously: 1. Uniform mixing and 2. lower pressure drop.

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  • Requirements: Species transport equations and composition dependent properties needed.

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  • Starting point: Species transport with properties independent on species concentration (passive scalar model) already implemented in SU2.

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  • Composition-dependent fluid properties model is not fully implemented  in SU2.

 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Goals

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  • Implement composition-dependent fluid model for species mixing for incompressible ideal gases.

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  • Test the capabilities of the present model through the numerical study of a Kenics static mixer.

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  • Investigate geometry parameters. 

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Mixing models: Composition-dependent fluid properties

  • Mean molecular weight:

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  • Density: 

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  • Mole fraction:

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Mixing models: Composition dependent fluid properties

  • Viscosity:
  • Wilke’s Method: 

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  • Davidson’s Method:

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Mixing models: Composition dependent fluid properties

  • Thermal conductivity:

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  • Specific heat capacities:

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  • Diffusion coefficient based on unity Lewis number assumption:

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Performance mixing models

 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Mixture viscosity of nitrogen-methane mixture for various temperatures.

Adapted from “Implementation and verification of turbulent species transport with composition dependent fluid properties in SU2” Heimgartner, M. Master thesis report (2021).

Diffusion coefficient for various temperatures.

Adapted from “Implementation and verification of turbulent species transport with composition dependent fluid properties in SU2” Heimgartner, M. Master thesis report (2021).

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Mixing models: configuration options

  • Enable composition dependent fluid properties model:

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  • Specify fluid properties for each species:

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similar for viscosity and conductivity.

  • Specify Viscosity model:

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  • Specify diffusivity model:

 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Kenics static mixers: Geometry

 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Kenics static mixers: Numerical setup

 Mixing model in SU2: A numerical study of a Kenics static mixer.

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  • Solver: Incompressible NS and RANS with SA model.
  • CFL: From 10 – 200
  • Meshing: GMSH
  • 648164 – 2272104 elements.

 

Walls

Inlet 1: Stream 1

Inlet 2: Stream 2

Outlet

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Velocity magnitude and mass fraction methane along the Kenics mixer

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Parameter study: blade thickness(a)

 

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Results: blade thickness(a)

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Parameter study: aspect ratio(AR)

 Mixing model in SU2: A numerical study of a Kenics static mixer.

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Results: aspect ratio(AR)

Start 2nd mixer element

Inlet

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Results: aspect ratio(AR) effects normalized per blade

Mixer 2

Mixer 3

Exit

Mixer 2

Mixer 3

Exit

Mixer 1

Entrance

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 Mixing model in SU2: A numerical study of a Kenics static mixer.

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Comparison with similar works: Reynolds number influence

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Conclusions

Current status:

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    • Good results compared with literature
    • Mixing laws seem to work correctly.

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Outlook:

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    • To be done: diffusivity, heat capacity in SU2.
    • Adjoint optimization of Kenics static mixer.

 Mixing model in SU2: A numerical study of a Kenics static mixer.

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