Conceptual Design of a Supersonic Jet Engine

Sammanfattning: This thesis is a response to the request for proposal issued by a joint collaboration between the AIAA Foundation and ASME/IGTI as a student competition to design a new turbofan engine intended for a conceptual supersonic business jet expected to enter service in 2025. Due to the increasing competition in the aircraft industry and the more stringent environmental legislations the new engine is expected to provide a lower fuel burn than the current engine intended for the aircraft to increase the chances of commercial success. The thesis has one main and one secondary objective, the main objective is to perform a preliminary design of a jet engine, complying with the specifications stated in the request for proposal. The secondary objective is to evaluate whether the knowledge gathered from the BSc program in aeronautical engineering at Mälardalen University is sufficient to perform this kind of study and to recommend courses for future students who wish to perform a similar project. Due to time restrictions a full conceptual design has not been performed and the work has mainly been focused on the thermodynamic and aerodynamic design phases. The thermodynamic analysis and optimization has been carried out using the Numerical Propulsion System Simulation (NPSS) code, where the cycle parameters such as fan pressure ratio (FPR), overall pressure ratio (OPR), turbine inlet temperature (TIT) and bypass ratio (BPR) have been optimized for cycle overall efficiency. With the cycle selected, and the fluid properties at the different flow stations known, the component aerodynamic design, sizing and efficiency calculations were performed using MATLAB, with equations and formulas found in the open literature together with literature developed at Chalmers University of Technology in Gothenburg, Sweden. Furthermore a number of research papers have been used for various parts of the thesis. Several aspects of the turbomachinery components have been evaluated to assure satisfactory performance. The result is a two spool low bypass axial flow engine of similar dimensions as the current engine but with increased efficiencies. A weighted fuel flow comparison of the two engines at the key operating conditions shows a fuel burn improvement of 11,8% for the new engine. The conclusions drawn by the authors on the secondary objective is that even though the knowledge might be slightly insufficient to undertake this type of task, with proper guidance and determination it’s certainly not impossible.