As part of an ongoing investigation into the effects of compressor fouling on gas turbine performance, the stage stacking technique was used in conjunction with generalized turbine characteristics to simulate the performance of two common pipeline engines, the G. E. LM2500 and the Solar Centaur. A linear fouling model was introduced that simulates the progressive buildup of contaminants in the compressor by modifying the appropriate stage flow and efficiency characteristics in a stepwise fashion. This simulation of the onset and progressive nature of compressor fouling allows quantitative analysis of performance deterioration to be performed on the basis of trends noted in monitored parameters. A preliminary study into how severely a given level of fouling will affect engines of different size indicated that stage loading may be the more critical parameter.

The Canadian Department of National Defence has identified a need for improved Engine Health Monitoring procedures for the new Canadian Patrol Frigate (CPF). The CPF propulsion system includes two General Electric LM2500 gas turbines, a high-pressure-ratio engine with multiple stages of compressor variable geometry. A general method for predicting the thermodynamic performance of variable geometry axial compressors has been developed. The new modeling technique is based on a meanline stage-stacking analysis and relies only on the limited performance data typically made available by engine manufacturers. The method has been applied to the LM2500-30 marine gas turbine and the variations in engine performance that can result from a malfunction of the variable geometry system in service have been estimated.

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Thermodynamic models suitable for use as diagnostic tools for pipeline gas turbines have been developed. A basic requirement was the prediction of the performance of gas turbines subject to in-service deterioration, including effects such as compressor fouling, foreign object damage and turbine damage. This was met by creating thermodynamic models capable of operation over the complete running range expected, with a provision for introducing arbitrarily controlled degradations. Models for a variety of types of gas turbines currently in pipeline use have been tested, demonstrating good agreement with user experience. The models are extremely flexible in use and may be used either for investigation of specific problems or to increase user understanding of operating problems.