Upgrade Evaluation of a Military Turbofan Engine

• Main Author: Andreadis, Eleftherios
• Other Authors: Pilidis, Pericles
• Language: en
• Published: Cranfield University 2011
• Online Access: http://dspace.lib.cranfield.ac.uk/handle/1826/4937

As the gas turbine technology advances, new features are incorporated to field engines. The new technologies can be implemented during upgrade programs, which improve the characteristics of the engines. It is observed that the current trend is the development of upgrade programs that increase the life of the engines and reduce the Life Cycle Cost, rather than programs that increase the performance of the engines. The main objective of the present thesis is to review the advantages and disadvantages of a real upgrade engine with increased life and of a hypothetical upgrade engine, whose increased life was converted into increased performance, using the same new technology. This thesis investigates a real life upgrade program, the Engine Enhancement Package (EEP), which was developed for the F100-PW-229 military turbofan engine and increases the life of the engine from 4300 cycles to 6000 cycles. This study highlights how the same new technology can be utilized to increase the performance of the engine instead of its life. The performance increase is achieved with the throttle push method, having as main results to increase the thrust by 1.14% and to decrease the life of the upgraded engine from 6000 cycles to 4300 cycles. This result was derived using the Larson Miller Parameter, which is used for the calculation of the creep life. This project provides a detailed assessment of the performance and the lifing of the engine before and after the upgrade in both cases (increased life and increased performance). The findings of this study provide to the military engine user useful information that can be used to determine one’s decision about accepting or not of an extended program like the upgrade presented in this thesis, given its particularly high cost. The main conclusion of this thesis is that the savings from the life increase are more valuable than the increased capabilities from the performance improvement. A similar study for a civil engine can draw significant results. In this case, the increased performance can be presented in terms of increased profit from the better fuel consumption, the increased range and the increased payload.