New methods of non-contact sensing of blade vibrations and deflections in turbomachinery

The paper is focused on new methods of non-contact sensing vibrations and deflections of rotating machine parts, especially blades of steam turbines. Special attention is paid to the induction and magnetoresistive sensors developed in the Institute of Thermomechanics for non-contact measurements of characteristics of rotating blades inside steam turbines under operation. Different principles of non-contact sensors based on measuring deflections or velocity components are described and compared, including new types of magnetoresistive sensors. Hitherto unpublished principles of sensors intended for shrouded blades are described and discussed.