Importance of Physics-Based Prognosis for Improving Turbine Reliability: RRA 501KB Gas Turbine Blade Case Study

Prognosis and health monitoring (PHM) technology needs to be developed to meet the challenges posed by aging gas and steam turbines in power plants, transportation systems, gas pipelines, and other industries. It is necessary to use physics based residual life prediction and life extension techniques to take into account the state of damage due to prior service. This paper focuses on the requirements of the technology and the state of the development to date. In this study, Life Prediction Technologies Inc.’s (LPTi’s) prognosis tool known as XactLIFE™ was successfully used to establish the fracture critical location of RRA 501KB first stage gas turbine blades under steady state loads and to compute the average life to creep crack initiation in the blade airfoils. The analysis used typical engine operating data from the field in terms of engine speed and average turbine inlet temperature (TIT). The blade is known to suffer airfoil untwist and lengthening during service and this is obviously followed by stress rupture failure. The primary objectives of the case study are to show how prognosis can allow a user to predict fracture critical locations to avoid failures.