In part I, a systematic humidity correction technique that can be used for any type of engine control mode is developed to predict the variation of engine performance due to inlet humidity. Limitation of conventional method is first identified and then, a new method is proposed to take into account the humidity effects on each engine component characteristics and to find the variation of equilibrium running point through a re-match process between the components with a given engine control variable depending on the humidity of inlet. Comparisons are made between two methods for a single spool gas turbine engine, and it is found that the conventional method leads to invalid correction when a physical variable such as rotational speed is controlled for engine operation in humid environment. It is also found that the accuracy of the conventional method depends on the engine control mode and the engine configuration. The proposed method can be used for any type of engine control mode and engine configurations.
In part II, high altitude effects on the gas turbine engine performance are analyzed by a semi-empirical method. Based on the existing correlations and test data, several performance correction methods for the turbomachinery are proposed. Using those correction methods, Reynolds number effects and mechanical power extraction effects on a small turbojet engine performance, depending on the operating altitude, are quantitatively and qualitatively analyzed.
