COMPARATIVE BEHAVIOUR OF PRESSURE RATIO, THERMAL DIFFERENTIAL AND VIBRATION SIGNATURES ACROSS MULTIPLE INDUSTRIAL GAS TURBINE UNITS

Abstract

Industrial power gas turbines suffer performance loss and these effects appear in their thermodynamics and mechanical variables. In this paper, the correlation of the Pressure ratio (PR) , the temperature differential  and the vibration signatures of four industrial gas turbines (GT1, GT3, GT4 and GT5) was compared along an 8 months inspection period (1,818 hourly points recorded). A comprehensive study was performed to analyze the relationships between these indicators and the failure patterns. Pressure ratio and temperature differential were considered thermodynamic derived variables, and vibration amplitude was measured following the ISO 10816-4 recommendation for industrial gas turbine units on fluid film bearings.  Vibration amplitude had the highest correlation to the occurrence of fault among the original sensors, r = 0.497. Temperature differential higher than 330⁰C had a high correlation with thermal degradation faults and the pressure ratio had a non-linear relationship with the probability of failure. Filter differential pressure showed a strong negative correlation to the pressure ratio 24 hour rolling mean (r = 0.618), demonstrating its effect over the overall compressor performance in the long term. The research provides a base on multi-parameter health monitoring methods for industrial gas turbines and also helps build prediction maintenance systems where the thermodynamic and mechanical properties can be fused.