Engine Performance Improvement by Controlling the Low Pressure Compressor Working Line

The new algorithm provides closed-loop control of the LP compressor working line in such a way as to maintain compressor stability and to provide increased power from the engine at the same firing temperature. This method is intended for the Trent 60, an aeroderivative engine designated for power generation and mechanical drive applications. The power benefit is achieved by operating at higher LPC pressure ratio and thereby increasing the inlet air flow and overall pressure ratio of the engine. Since the algorithm controls the working line, the threats to compressor stability related to the working line level are removed (including production scatter, deterioration, and fouling) and the required surge margin can be safely reduced, providing a significant benefit in engine performance. The paper presents comparatively the structure of the current and new concepts, the main features of the controller, and stresses the improved accuracy and reliability of new algorithms. The performance benefit is then assessed; the increase in power is about 3% at ISO, sea level conditions and varies with ambient temperature.