Abstract

In this study, an assessment of degradation and failure modes in the gas-path components
of twin-shaft industrial gas turbines (IGTs) has been carried out through a model-based analysis.
Measurements from twin-shaft IGTs operated in the field and denoting reduction in engine
performance attributed to compressor fouling conditions, hot-end blade turbine damage, and failure
in the variable stator guide vane (VSGV) mechanism of the compressor have been considered
for the analysis. The measurements were compared with simulated data from a thermodynamic
model constructed in a Simulink environment, which predicts the physical parameters (pressure and
temperature) across the different stations of the IGT. The model predicts engine health parameters,
e.g., component efficiencies and flow capacities, which are not available in the engine field data.
The results show that it is possible to simulate the change in physical parameters across the IGT during
degradation and failure in the components by varying component efficiencies and flow capacities
during IGT simulation. The results also demonstrate that the model can predict the measured field
data attributed to failure in the gas-path components of twin-shaft IGTs. The estimated health
parameters during degradation or failure in the gas-path components can assist the development of
health-index prognostic methods for operational engine performance prediction.