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24.4.2014 : 20:46 : +0200

Transient analysis of a scroll compressor with ANSYS

Fluid loading on moving enclosures

Transient analysis of a scroll compressor with ANSYS


The scroll compressor consists of a stationary and a orbiting spiral, which are nested. During the movement of the orbiting spiral, the number, shape and volume of the internal chambers is constantly changing. Consequently, the pressure conditions in the chambers are changing as well.

The aim was to investigate the following aspects using FE simulation:

  • Automatic detection of the continuously changing chambers and their corresponding internal pressure using analytic approach instead of traditional FSI approach
  • Realistic compressor kinematics
  • Transient effect at operating speed of 9000 RPM


First, it was necessary to automatically detect the varying number of chambers, their shape and also their seclusion. An extended polygon-selection was also required to select the areas of pressure application.
For this purpose some APDL routines have been developed and integrated as Command Objects in ANSYS Workbench. Joints that came from the multi-body simulation and nonlinear contacts served to model the compressors complex kinematics realistically. With the help of ANSYS HPC the time to calculate the transient analysis could further be reduced.

Customer Benefit

Previously it was necessary to model the pressure generation chamber accurately in a CAD system for each rotation angle. The pressure must be “calculated by hand” and transferred manually – a tedious and error-prone process.

  • Using the automated chamber detection and pressure application, the customer can “effortless” run simulation for any given angle.
  • An insight on the inner working forces of the critical components at high speed is possible.
  • The use of ANSYS HPC reduces the overall elapsed transient simulation time.

Consulting_Flyer_Sanden_Scroll_Compressor_Transient.pdf [380kB]