ABSTRACT
The gas turbine cycle is best depicted by the Brayton Cycle. The characteristics of the operating cycle are shown on the the pressure-temperature map, the pressure-specific volume map, and the temperature-entropy map. The efficiency of each module contributes to the overall efficiency of the gas turbine. The ability to examine the efficiency of each module or component is a necessary tool in isolating engine problems. Compressor efficiency (r/c) is directly proportional to the compressor pressure ratio and inversely proportional to the compressor discharge temperature. Tracking or trending turbine efficiency would be an excellent method to monitor the health of a unit. This is the total horsepower produced by the turbine. It includes the horsepower to drive the compressor and, for single shaft machines, the power used by the driven load. Compressor performance is generally shown as pressure ratio plotted against airflow.
