Status of gas turbine performance degradation

Any prime mover exhibits the effects of wear and fouling over time. The degradation affects the performance of such a machine. For a industrial gas turbine, the problem includes predicting the effects of wear and fouling on the performance of such an engine, as well as the description and determination of the mechanisms that cause wear and in particular fouling. The degradation effects can be classified in several categories, for example recoverable vs. non - recoverable degradation, alluding to the fact that cleaning the engine is possible for some types of degradation. Another differentiation is fouling, where fine particles adhere to blade surfaces as opposed to material removal from heavier particles or rubbing. The systematic attempts to determine degradation mechanisms, their impact on gas turbine performance, and mitigation methods go back several decades. More recently, simulation methods have closed the gap between observed contamination and numerical results. The deterioration of gas turbine components, such as the compressor or turbine sections result in a performance reduction that depends on the operating conditions of the engine, and is, for example dependent on the prevailing ambient conditions and the load of the gas turbine. This paper attempts to reflect the state of the art theoretical and practical results.