Gas Path Fault and Degradation Modelling in Twin-Shaft Gas Turbines

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.

Performance Calculation of a Multi-Stage Axial Compressor through a Semi-Empirical Modelling Framework

“…The parameter λ is considered to represent all the losses across the compressor barring those mentioned above. This modelling process will simplify the construction of the overall compressor map at different operating conditions and provides flexibility in the integration of the 1-D model with gas turbine models (Cruz-Manzo, et al, 2018) comprising 0-D model components.…”

“…This developed modelling architecture could provide flexibility for the integration of the 1-D compressor model within the whole gas turbine models (Cruz-Manzo, et al, 2017;Panov, 2009) commonly comprising 0-D individual component models. In a previous study (Cruz-Manzo, et al, 2018) the change in air temperature and air pressure discharged by an axial compressor during fouling conditions was simulated through a Simulink 0-D gas turbine model. The simulation results were validated against real measurements and the analysis consisted of an empirical modification of flow capacity and efficiency from the compressor.…”

“…An additional test case in which the effect of IGV position outside of its nominal schedule on stage performance was carried out. Further development of this modelling framework could provide an insight into the effect of different compressor failure \ degradation modes (Cruz-Manzo, et al, 2018) such as fouling and out of position VGV on different stages of the axial compressor.…”

“…Thereafter, the deviation angle δ is reduced to 2.25 for the rest of the stages. These values are considered to be representative of a fouled compressor after many hours of compressor operation, (Cruz-Manzo, et al, 2018). Fig.…”

“…In future the dynamic reduction of stagewise performance in the compressor under fouled conditions will be studied. In a previous study (Cruz-Manzo, et al, 2018) simulation of compressor fouling conditions, using a Simulink engine model comprising a 0-D compressor model and real-world validation data from engines operated as mechanical drivers and power generators, has been carried out. In future work, the 1-D compressor modelling architecture developed in this study will be incorporated into a Simulink engine model to predict and validate reduction in engine performance attributed to compressor fouling conditions.…”