Monitoring the Precession of Gas Turbine Engines Rotor Systems and Evaluating the State of Inter-Rotor Bearings

. Evaluation of the technical condition of gas turbine units, widely used in power engineering, oil and gas industry and aviation, is an important and complex scientific and technical problem. One of the most important elements that has a significant impact on the quality and reliability of the gas turbine unit is its rotor system. Dynamic mechanical interaction between the rotors and inter-shaft bearing caused by counterphase motion of the mass centers of the rotors or the precession axes can lead to a sudden failures causing bearing breakage in the two-loop gas turbine engines. It has been assumed in the paper that sudden failures are caused by accumulated, total fatigue of the bearing material arising because of shock cyclic bearing loads due to the precession of the rotors. It has been shown that the technical condition could be evaluated using vibration monitoring the precessional motion of the rotors and constructing its trajectory in the normalized, using the fatigue curve of the material, phase plane. Using the new intellectual technology of automated estimation of control object state with use of concepts “programming without programming” and the level intersection theory, vibration curves and phase trajectories were analyzed to determine the characteristics of load cycles. This makes it possible to estimate the residual resource value of the inter-rotor bearing assembly. The proposed approach possesses essential scientific novelty to the estimation of the effect of vibrations on individual units and mechanisms of gas turbine systems and can be used for creating compact field-level devices.