OPR-free single probe blade tip timing for monitoring rotating blade

Condition monitoring is crucial for a rotating blade working in harsh conditions. Blade tip timing (BTT) is a potential technique for operational blade health monitoring owing to its non-contact and efficiency, which identifies the vibration parameters characterizing the blade condition. However, severe undersampling and difficult probe/sensor installation hinder its application. Moreover, minimizing probe number, including once per revolution (OPR) sensor, to reduce modifications to turbomachinery is advocated in the field of health monitoring, especially for high-end equipment, such as aero-engines. In this paper, we proposed a single probe OPR-free BTT based parameters identification method for both synchronous and asynchronous vibrations. To avoid the use of OPR signal, rotating including angle (RIA) replaced the tip displacement as a signal to be analyzed. In addition, a sampling aliasing frequency (SAFE) map was constructed using the RIA signal, which provided the guidelines for parameter identification. Finally, the effectiveness and robustness of the proposed method were validated by a series of simulations and experiments. By reducing installation and hardware costs, the proposed method significantly improved the practicability of BTT measurement.