Preliminary design and analysis of supersonic business jet engines

Abstract

Currently projected supersonic business jets target selected supersonic flight missions with Mach numbers of about 1.4 and a larger number of long-range subsonic flight missions. They form a new type of aircraft that is specially tailored to these requirements. The question arises as to which engine configurations and technology levels are required to support these new applications. This is addressed firstly by exploring the design space of potential working cycles. An aircraft model is used to translate the results of the cycle study into an expected aircraft range. An optimal core engine and fan configuration result from the cycle study and the derived mission ranges. The preliminary design of the low-pressure components is investigated in the second step based on the optimal core configuration. The highest non-dimensional parameters are encountered in subsonic flight conditions. The highest dimensional parameters are encountered in supersonic high-altitude flight conditions. High-overall-efficiency configurations do not result in optimal aircraft ranges. There is an optimal number of two fan stages and a specific thrust of about 300 m/s, resulting in a maximum aircraft range that is 11% superior to that achievable with a single-stage fan. A fan hub-to-tip ratio range that is comparable to that of military fans is desirable, with an aerodynamic lower limit around 0.37. The low-pressure turbine stage count is a compromise between turbine mass and size.