Institute of Fluid Machinery

Fans - Design and Optimization

Development of design tools

At the Institute of Fluid Machinery specialized numerical tools are developed for the design and optimization of axial, radial and diagonal fans. They are based on classical design approaches. To get a deeper insight into the aerodynamical behaviour of the fan the tools have interfaces to CFD-methods.


Fig. 1: Profiles of a axial fan blade - meridional section of a radial fan



  • Designtools for axial, diagonal and radial fans
  • Used Software: MATLAB, Excel
  • Interface to CAD-methods (Rapid-Prototyping)
  • Interface to CFD-methods
  • Interfaces to optimization tools




  Fig. 2: GUI of the design-tool

Computational Fluid Dynamics

Methods of Computational Fluid Dynamics are used to investigate the aerodynamical behaviour of the fluid machine in detail. Spatial discretization of the fluid domain is done by blockstructured and unstructured meshes. The time-consuming calculations are executed in parallel on different clusters at the Institute of Fluid Machinery.


Spatial discretization - meshing

Netz im Schaufelkanal


  • Fully automated meshing using blockstructurred and unstructured grids
  • High resolution at the boundary layer and at geometry parts of special interest(gap, spiralcasing tonque etc.)




  Fig. 3: Blockstructured mesh inside the blade channel


Solving the flow problem

  • Use of commercial Software, Open-Source Software (OpenFOAM®, OpenFOAM®-ext) and the CFD-code of the institute SPARC
  • Calculation on clusters of the institute (approx. 200 CPUs) and of KIT (>1000 CPUs)



  • Calculation of characteristic values of the fluid machine (volume flow, pressure rise, power consumption)
  • Analysation of occuring flow phenomenas (secondary flow, separations)
  • Quantification of occuring losses


      Fig. 4: Result of a radial fan