Abstract: A method is provided for evaluating stall/surge margin of a machine of interest. The method includes identifying a vital factor where each the vital factors corresponds to operation of the machine of interest. Raw data relating to the vital factor is provided. A contribution of the vital factor to the stall/surge margin is determined from at least the provided raw data. The contribution of the vital factor to the stall/surge margin is statistically analyzed. A stall/surge margin is allocated based on the statistical analysis of the contribution of the vital factor. An operating limit line is defined based on the allocation of the stall/surge margin.

Abstract: A method is disclosed for monitoring and controlling a compressor including (a) monitoring at least one compressor parameter; (b) storing data indicative of the monitored parameter in a database system; (c) processing the collected data using a stall precursor detection algorithm to determine a stall precursor; (d) comparing the stall precursor with at least one of a corresponding average compressor value, and a corresponding unit specific value to determine the level of compressor operability, and (e) if the stall precursor varies from at least one of the average compressor value and the unit specific value, performing corrective actions to vary the level of compressor operability to prevent a surge condition.

Abstract: A method is provided for evaluating stall/surge margin of a machine of interest. The method includes identifying a vital factor where each the vital factors corresponds to operation of the machine of interest. Raw data relating to the vital factor is provided. A contribution of the vital factor to the stall/surge margin is determined from at least the provided raw data. The contribution of the vital factor to the stall/surge margin is statistically analyzed. A stall/surge margin is allocated based on the statistical analysis of the contribution of the vital factor. An operating limit line is defined based on the allocation of the stall/surge margin.

Abstract: A transfer function between the inlet air-flow consumed by a Gas Turbine engine, and the engine parameters of speed, pressure ratio, and Inlet Guide Vane (IGV) angle is described. An active compressor Operating Limit Line (OLL) management strategy that leverages this improved flow measurement transfer function is also described. The improved flow measurement capability afforded by the transfer function permits a deterioration in flow rate caused by compressor fouling to be detected. Using the deterioration in flow rate as a proxy for compressor fouling, a degraded surge boundary associated with fouling can be predicted, using a transfer function between degradation of air-flow along operating line and degradation of surge line. In combination, the inventive improvements in flow measurement and operating line management afford added compressor surge protection across the operating range, while permitting the attainment of elevated pressure ratios associated with high thermodynamic efficiency and output.

Abstract: A gas turbine operational strategy is provided for the optimization of ISO-Day rated performance. The invention is realized by setting the nominal operating line equal to or slightly below the operating limit line, so that ISO full load performance is maximized. Thus, the first stage turbine nozzle throat area is sized such that, without inlet bleed heat addition, and at Base-Load pressure ratio and firing temperature, the compressor operates within its operational limits on a ISO day. As ambient conditions change, levels of inlet bleed heat and firing temperature are controlled and the inlet guide vane angle is set whereby the nominal operating line is equal to or slightly below the operating limit line.

Abstract: The surge pressure ratio of a compressor is determined by transiently reducing the inlet flow to the compressor to increase the compressor pressure ratio sufficiently to produce the surge pressure ratio. The reduction in flow of fluid is maintained for a time period insufficient to exceed the exhaust gas temperature limit for the turbine. The area of the first-stage nozzle of the turbine is reduced and the inlet flow to the compressor is reduced to a steady state to achieve pressure ratios, in close proximity to the surge line. By transiently further reducing the inlet flow to the compressor and then increasing the inlet flow back to the steady-state condition, the surge pressure ratio can be obtained without exceeding machine operational limits.