Chemically Reactive Flow of Hot Combustion Gases in an Aircraft Turbo-Jet Engine

Abstract

Current progress in gas turbine performance is achieved mainly by increasing the turbine inlet temperature. State-of-the-art military aircraft gas turbines operate with turbine inlet temperatures exceeding 2000 K, and future development plans call for even higher temperature levels. At such high temperatures, the hot combustion gases can no longer be considered as chemically inert, and it becomes important to account for the chemically reactive nature of the expanding flow. In this paper, the authors present a one-dimensional model of the chemically reactive flow through the first turbine stage of an aircraft turbo-jet engine. The model is used to study the impact of chemical reactivity on pollutant emission characteristics and engine performance (i.e., overall efficiency and specific thrust). Three different flight conditions are considered: sea-level static operation (take-off), subsonic cruising at 10000 meters altitude, and supersonic flight at 20000 meters altitude. The results of this study show that typical flight conditions and operating parameters of turbo-jet engines produce high pollutant emission levels and decrease overall efficiency and specific thrust.