ABSTRACT
As with any piece of mechanical equipment, the gas turbine is susceptible to a wide variety of physical problems. The objective of the gas path analysis is to detect as many problems as is sensibly and economically feasible through the observation of suitably chosen parameters. To be detectable, the problems must be of a nature and magnitude to produce an observable change. Cracks in combustors, stators, nozzles, blades, or discs are not detectable through gas path analysis. Turbine blade oxidation, corrosion and erosion is normally a longtime process with material losses occurring slowly over a period of time. Geometry changes resulting from oxidation, corrosion, erosion, or impact damage can be corrected only during overhaul by removal and replacement of the damaged parts. Furthermore, trailing edge losses are more tolerable than leading edge losses. Compressor fouling normally occurs due to foreign deposits on the airfoils.
