Engine Performance Improvement by Controlling the Low Pressure Compressor Working Line

Abstract

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 aero-derivative 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.

Off-design performance improvement of twin-shaft gas turbine by variable geometry turbine and compressor besides fuel control

“…The amount of power improvement for an industrial gas turbine at ambient temperature from 25 to 45 C is reported to be about 3% in some reference. 1 However, in that reference, only IGV angle was adjusted and the compressor operating point become close to the surge line (lower surge margin). It should be noted that the engine power output in load control mode is set to be at the optimum value of power output in TIN control mode (Table 7) for comparison of the life cycle results.…”

“…Martis et al 1 proposed a new closed-loop control algorithm for IGV and bleed valve opening to increase the pressure ratio while compressor stability is also maintained. This provides power output and efficiency increase without any augmentation in turbine inlet temperature (TIT).…”