Rotor test rigs

The Institute of Energy Systems is equipped with two test rigs for experimental investigations on sealing systems for turbomachines. The double-flow, modular setup facilitates the integration of many different sealing systems and their examination at varying operating conditions. A special feature is the swirl generator using an internal bypass and downstream compressor which allows the variation of pre-swirl velocity in a wide range, independently from leakage flow and inlet pressure.

In particular, the leakage behavior and the rotordynamic coefficients can be measured at different static and dynamic operating points. By means of corresponding measurement equipment, the evaluation of friction torque and chamber flow as well as the visual investigation of the flexible seal behavior are possible, too.

No-whirl experiment

On the no-whirl test rig the leakage mass flow and the pressure distribution in the sealing chambers (32 pressure measurement points) can be measured at varying rotor static eccentric positions, rotational speeds, pressure drops and pre-swirl velocities. By integrating the pressure distribution the stiffness coefficients of the seal configuration can be obtained.

  • Inflow pressure: 0 … 10 bar
  • Rotational speed: up to 12,000 rpm
  • Surface speed: 0 … 113 m/s
  • Pre-swirl velocity: 80 … 300 m/s
  • Rotor eccentricity ratio: 0 … 1
  • Measurement of leakage mass flow and pressure distribution

Dynamic experiment

The dynamic test rig allows the measurement of the rotordynamic stiffness coefficients, as well as the determination of the damping coefficients. This is accomplished by exciting the rotordynamic system to its stability limit with the help of a magnetic actuator and the interacting aerodynamic forces within the seal.

  • Inflow pressure 0 … 5 bar
  • Surface speed: 0 … 15 m/s
  • Pre-swirl velocity: 80 … 300 m/s
  • Electromagnetic actuator for non-contacting rotor excitation
  • Position measurement for rotor vibration monitoring
  • Direct identification of specific aerodynamic forces