Exhaust Gas Turbocharger

  Bird eye view on test rig Copyright: © IKDG  

The exhaust gas turbocharger test rig was developed to investigate blade vibrations. The open design is advantageous for this purpose. The turbine and compressor are completely decoupled from each other to prevent excitation between them.

Two different measurement methods, e.g. dynamic pressure measurements, strain gauges and blade tip timing, can be used to record the vibration modes:

  • Local strains of the blades can be measured by strain gauges.
  • In blade-tip timing, on the other hand, the blade arrival times at the respective measuring positions are recorded, from which a slow or fast arrival of the blade and thus the tangential deflection can be calculated. The vibration mode is determined from the change in deflection between the measuring positions.

The open design in combination with many control options for the air supply also makes it possible to measure the entire characteristic map of the turbomachine.

The air supply to the exhaust gas turbocharger is provided by the institute's compressor systems. Here, a 6-stage centrifugal compressor provides the mass flow for the radial turbine. The inlet temperature of 220°C is achieved with an electric heater, while a natural gas-fired heat exchanger is used for the inlet temperature of 500°C.



  • Investigation of blade vibrations in the radial turbine of an exhaust gas turbocharger.
  • Investigating the change in blade vibrations of a specially tuned radial turbine.

Measurement Technology

  • Strain gauges on the blades of the radial turbine.
  • Blade tip timing (sampling rate 100 MHz)
  • Dynamic pressure measurements in the casing of the radial turbine
  • Stationary pressure measurements in the inlet and outlet planes of the exhaust gas turbocharger, as well as in the guide vane grid and housing of the radial turbine
  • Temperature measurements (thermocouples and resistance thermometers) in the inlet and outlet planes of the exhaust gas turbocharger.
  • Speed measurement

Technical Data

Max. air mass flow [kg/s]


Max. pressure ratio [-]


Turbine inlet temperature [°C]


Max. speed [1/min]