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Short-term performance deterioration in JT9D-7A(SP) engine 695743The level of performance deterioration that occurred during early service was studied and also the contribution of each engine module to the overall level of engine performance deterioration. To assist in the distribution of the performance losses to the module level, testing with expanded experimental instrumentation was accomplished to permit direct measurement of module performance. An analytical teardown of the engine was accomplished to permit assignment of module performance losses to individual mechanical damage mechanisms including blade and seal wear, roughness, and thermal distortion of turbine parts. The results of the testing show that the engine deteriorated 1.5 percent in thrust specific fuel consumption from its performance when new. Initial testing, which included water washing, showed that 0.2 percent in performance deterioration was due to surface contamination (dirt) and 0.1 percent was due to drift of the engine vane control system, leaving 1.2 percent in basic TSFC deterioration. This 1.2 percent TSFC loss was distributed among the engine modules with 0.6 percent caused by clearance changes, 0.4 percent loss due to thermal distortion, and 0.2 percent loss due to increased roughness of the fan and low-pressure compressor airfoils.
Document ID
19780022178
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Bouchard, R. J. (Pratt and Whitney Aircraft Group East Hartford, CT, United States)
Beyerly, W. R. (Pratt and Whitney Aircraft Group East Hartford, CT, United States)
Sallee, G. P. (Pratt and Whitney Aircraft Group East Hartford, CT, United States)
Date Acquired
September 3, 2013
Publication Date
June 30, 1978
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
NASA-CR-135431
PWA-5512-17
Accession Number
78N30121
Funding Number(s)
CONTRACT_GRANT: NAS3-20632
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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