Development and improvement of compressor performance prognostics for US Navy gas turbine engines

In December 2003, Naval Surface Warfare Center Gas Turbine Emerging Technologies section conducted land-based fouling testing on a Rolls Royce/Allison 501-K17 gas turbine engine. The purpose of this testing was to collect data to improve a previously developed compressor health prognostics algorithm. For the purpose of Phase I of this testing, fouling was accomplished by injecting salt into the gas turbine inlet air stream. Phase II of this testing will consist of fouling the middle and back regions of the compressor. Influence coefficients can then be developed for each of these regions indicating how a given region affects overall performance. Typically, in a marine environment, fouling of the front stages occurs due to ingested salt while fouling in middle and rear regions occurs from a combination of ingested salt and oil seal leakage. In order to monitor engine performance, it was necessary to add several sensors to the existing test cell. In addition, hardware was added to both ingest and monitor the concentration of salt in gas turbine inlet air. Preliminary results from Phase I indicate that front stage compressor fouling causes a clear increase in inlet static pressure. This is due to the mass flow restriction through the compressor. Additional results are currently being summarized and data is being utilized to improve the 501-K17 compressor performance algorithm previously noted