Sustainable Supersonic Transport: a Case Study on Variable Pitot Inlets
Creators: name:  S. KAZULA 
name:   K. HOSCHLER 
Publisher: name: Proceedings of  the 9th European Conference for Aerospace Sciences. Lille, France, 27 June - 1 July, 2022
Year: 2022
Subjects: SYSTEM INTEGRATION
AERONAUTICS

description: Abstract An overview of aero-engine inlets, the design process in aviation and a safe design approach for academic studies is provided. By means of a safe design approach, a variable inlet concept is developed up to technology readiness level (TRL) 3 and described. The application of safety and reliability methods, aerodynamic and structural analyses, as well as functional demonstrators proves the feasibility of the present variable inlet concept and highlights its potential for application in future supersonic transport (SST). Keywords: Variable Pitot Inlet; Supersonic Transport; Concept Development Introduction Achieving high efficiency, reliability and safety are major goals for future aviation [1]. This affects projected applications for supersonic transport (SST) in particular. Variable pitot inlets that adjust the inlet geometries for different flight conditions can be a way to attain high efficiency by reducing the aircraft drag [2]. Furthermore, they can support the prevention of engine surge during operation at high angles of incidence or crosswind. Hence, variable inlets have been investigated in a number of subsonic studies [3], [4], [5]. As subsonic variable inlets are currently not in use, potential reasons for this absence of application are that their limitations concerning complexity, reliability and costs outweigh their provided aerodynamic benefits. Variable pitot inlets for SST applications up to Mach 1.6 offer higher aerodynamic benefits, which could compensate these limitations [6]. Furthermore, variable pitot inlets have several advantages over other supersonic inlet types in terms of flow uniformity, length and weight. The increased complexity of a variable inlet system can entail reliability and safety issues. These issues can be addressed by the application of a safe design approach. This paper presents the development of a variable inlet concept for SST by means of a safe design approach. First, an overview of aero-engine inlet design is given. The design process in aviation according to Aerospace Recommended Practices ARP 4754A [7] is described. Subsequently, the applied safe design process is introduced. Based on this process, the development of a feasible variable inlet concept is explained. The feasibility of the concept is proved by analyses and functional demonstrators, whereby TRL 3 is achieved. These results highlight the high potential of variable pitot inlets for future SST. Results and Conclusions The development of a TRL 3 concept for variable inlets for SST by means of a safe design approach has been presented. An overview of inlet design and the design process in aviation has been given. The applied safe design process has been introduced and utilised to develop a feasible variable inlet concept. Results from earlier safety, reliability, aerodynamic and structural analyses as well as the two manufactured functional demonstrators prove the feasibility of the inlet concept, see Figure 1. Thereby, TRL 3 is achieved and a potential range benefit of 20% up to 30% is determined. The concept can achieve TRL 4 by further analyses and an increased level of detail. For instance, bird strike and flow analyses should be conducted to prove the structural and aerodynamic capabilities of the final concept. Finally, tests must be performed to validate the results from these analyses. These tests can also be used to show compliance with the certification specifications. The results of this paper highlight the high potential and feasibility of variable pitot inlets for future SST. Further concept investigations potentially enable this technology for future aircraft and this way, contribute to achieve high efficiency, reliability and safety in SST.