A Parametric Cycle Analysis of a Triple-Spool, Separate-Exhaust, Turbofan Engine with Inter-Stage Turbine Burners

This study investigates the parametric cycle analysis of a triple-spool, separate-exhaust turbofan engine with inter-stage turbine burner (ITB). A typical conventional triple-spool, separate-exhaust turbofan engine has been selected as the baseline engine for this study. The baseline engine cycle is modified to introduce an isobaric inter-stage turbine combustion chamber which is placed in the transition duct between the high-pressure turbine (HPT) and the intermediate pressure turbine (IPT). Engine cycle design parameters such as compressor pressure ratio, fan pressure ratio, by-pass ratio, and HPT inlet temperature are varied parametrically. The main performance parameters of the modified engine cycle (specific thrust and thrust specific fuel consumption) are estimated and compared against those of the baseline engine cycle subject to design limitations due to maximum attainable component efficiencies, and maximum allowable turbine temperatures. The results showed that the implementation of ITB has significant effects on engine performance parameters, in addition to its potential to lower NOx emissions compared to the baseline engine.