Measurement and assessment of turbine rotor speed instabilities in applying the BTT method

The paper deals with the measurement and assessment of rotor speed instabilities. Mean attention is paid to measurements on turbine rotors while using the Blade Tip-Timing Method. In this case, the rotation speed instability can lead to systematic errors and significant measurement inaccuracy. The problematic was investigated on a model test turbine wheel of in the Laboratory of the Rotational Laser Vibrometry in the Institute of Thermomechanics AS CR. For the data evaluation have been used both deterministic and statistical mathematical methods and procedures. Especially statistical methods offer new perspectives on the studied phenomena.