Method and system for monitoring rotor blades of a turbomachine using blade tip timing (BTT)

A system configured to determine vibration characteristics of moving rotor blades in a turbomachine comprising a housing and rotor including a shaft with the rotor blades attached thereto, using Blade Tip Timing (BTT), the system comprising:

• at least one proximity sensor operable to measure a Time-of-Arrival (ToA) of a proximate tip of a moving rotor blade;
• a memory module communicatively coupled to the sensor and configured to store, at least temporarily, timing data indicative of a plurality of ToA measurements of the rotor blade;
• and
• a control module communicatively coupled to the memory module and configured to:
• manipulate the stored timing data signals to determine a corresponding blade tip deflection at each measured ToA;
• express the blade tip vibration as a Bayesian statistical model consisting of intermediate model parameters representing vibration amplitude, frequency, phase, and offset, wherein model coefficients in the statistical model are probabilistic quantities;
• express the determined blade tip deflections as observed values in the statistical model;
• manipulate the intermediate model parameters in the statistical model using Bayesian linear regression or Bayesian inference thereby to estimate the intermediate model parameters and consequently vibration behaviour of the rotor blade;
• and
• assess, through an appropriate goodness-of-fit criteria or Bayesian model evidence, accuracy of the determined model coefficients.