Aerodynamic study of airframe-engine integration of a supersonic business jet

An increasing number of institutions and companies is recently showing increasing interest in supersonic and hypersonic flight with particular focus on sub-orbital flight and high-speed point-to-point transportation. In this scenario, the University of Naples “Federico II” is currently studying advanced concepts of supersonic/hypersonic aircraft and suitable high-speed propulsion system integration for efficient travel in the Mach 4-5 speed range. Within this framework, a collaboration is in progress with the SME Blue Engineering. In the present work a study is undertaken to investigate the performances along with aerodynamic design of the supersonic intake for the turboramjet engines and the engine-airframe integration for a Mach 4 supersonic business jet. Firstly, attention is focused on directional stability and trimmability enhancement acting on aircraft configuration. The following section is dedicated to the aerodynamic design of a high-efficiency intake adapted to different flight conditions. To conclude, the last section addresses the sensitive issue of airframe-engine integration. The configuration analysis has been carried out with the quick and low-cost software Missile DATCOM, well suited for aircraft preliminary design. For the supersonic intake aerodynamic design and the airframe-engine integration analysis, the commercial Navier-Stokes solver Siemens STAR CCM+ has been used. An improved configuration has been proposed, actioning on vertical tail and wing for the directional stability enhancement, while the trim conditions have been improved using a canard. As for the supersonic intake aerodynamic design, the choice fell on mixed-compression variable-geometry. In particular, a total spike forward translation of 0.65 m guarantees adaptive operations along the supersonic trajectory. In addition, the choice of mixed-compression configuration ensured high efficiency values thanks to the multiple shock waves’ reflection in the supersonic diffuser. For what concerns the engine-airframe integration, the engine location above the wing has been shown to be not suitable due to the strong aerodynamic interference that reflects in a completely off-design intake functioning. Therefore, the configuration has been upgraded integrating the engine with the wing avoiding the issues experienced in the previous case