Design of Innovative Environmental Control Systems for high-speed commercial aviation

The Environmental Control System, ECS, represents a constant power demand over the complete flight envelope, regardless of engine power settings and engine speeds. ECS objective is to create a suitable environment by controlling the environmental parameters, providing resources, and managing waste products. The Thesis is part of the H2020 STRATOFLY project that study the feasibility of a Hypersonic civil passenger transport aircraft concept, STRATOFLY MR3, that shall be able to cruise at 30 km altitude and Mach 8 flight speed with the primary goal to reduce flight time, noise and emissions. It is about an innovative way of conceiving air transport and so it is an interesting challenge for scientists and researchers since the idea is ambitious and probably will change the aerospace industry from the field of high-speed propulsion to high-temperature resistant materials. This is the challenge that awaits the years to come and it will radically change the way of conceiving the Earth and humanity itself. This thesis focuses on the definition, design, sizing and simulation of the Environmental Control System for hypersonic civil aviation. It is about an innovative to conceive this subsystem and it is never experienced before. At subsonic and supersonic speed, until Mach3, Open - Loop ECS is assumed, in order to perform immediately using key-enabling technologies that are technologically ready. This kind of solution is actually used in commercial long-range aviation. From Mach 3 to Mach4 there is a transitional phase in which Open and Closed Loop coexist: in this step an air tank is refilled in order to compensate air leakage during Closed Loop phase. At hypersonic speed full closed-loop system is the optimal solution given present data. Carbon Dioxide Removal Assembly and Trace Contaminants Control Subassembly are responsible for remove CO2 and contaminants in order to provide clean air to passengers. The target of the work is to define a proper architecture for the subsystem and verify its compliance to the mission. First of all, stating from the information of cruise speed and using the zero-dimensional steady-state analysis based upon a convective-radiative-conductive heat transfer balance it is obtained skin temperature and heat penetrating across the hot insulation layer. After computing the heat loads that the ECS shall withstand in operation, the necessary airflow to cool down the cabin into +18°C to +25°C temperature range is obtained and then it is compared to the mass flow rate required for breathing. After that architecture design is hypothesized and open to future development, for example using CO2 from CDRA to create Oxygen exploiting Sabatier reaction or exploiting electrolysis to use water condensate in Air Cold Machine in order to produce Oxygen to enrich the air in the cabin and Hydrogen that could be send to liquid hydrogen tanks for improving range autonomy.