Electrostatic Engine Monitoring System - A Progress Paper

This paper presents the Electrostatic Engine Monitoring System (EEMS(TM)) concept of gas turbine health monitoring being developed by United Technologies Corporation for eventual incorporation in the engines of both rotary wing and fixed wing aircraft, as well as other turbine engine applications. The EEMS concept is a gas turbine health monitoring system which provides early warning of several forms of engine degradation. Engine degradation that produces particulate matter or ingestion of particulate matter provides sites for the accumulation of ionically imbalanced charges in the gas path. Various combinations of physical, aerodynamic and electrical. processes. within the engine foster the production of ionized gas "clouds" in the gas path. These "clouds" persist long enough to exit the engine before recombination and can thus be detected and analyzed. The EEMS concept monitors for the presence of and counts the occurrence of these ionically imbalanced clouds in the gas path. The occurrence and nature of these clouds have been shown to be reliable indicators of engine deterioration. This paper presents a brief overview of the EEMS concept operating principles followed by a short historical note which traces its long and successful development to date. Under development at United Technologies since 1980, present activities are reviewed together with some comments on future applicability.