Session: 01-14 Thermal Management and Aero-engine Oil Systems II

Paper Number: 122353

122353 - Thermodynamic Modelling of Air Management System for Commercial Aircraft Environmental Control Systems 

The Environmental Control System (ECS) maintains the aircraft cabin habitable for passengers at higher altitudes. It is one of the principal non-propulsive energy consumers on the aircraft. On average for a short-medium-range airplane at cruise, the ECS will consume 35-40% of the total power off-take of the engine. For that reason, extensive research has been dedicated to evaluating the engine efficiency improvements enabled by reducing the power required by the onboard systems; one prominent approach is changing the ECS architecture to a hybrid- and/or electric concept. The engine efficiency improvement potential of the ECS electrification correlates with system-level challenges such as added weight of the electrical systems and other impacts that can snowball into whole-aircraft performance penalties. One such challenge that has not been thoroughly addressed in the literature is the design of the Air Management System (AMS), whose function is to supply the pressure- and temperatureconditioned air to the ECS. In the conventional paradigm, the AMS is situated between the engine compressor bleed and the ECS inlet, whereas for the electrified architectures it can be configured differently.

 

This paper presents a thermodynamics-based model of the AMS dedicated to preliminary design of the system. This development aims to open the design envelope to the range of theoretically possible ways of conditioning the exterior air and/or bleed air (depending on the ECS architecture of interest). With that visibility, it should be possible to design an AMS that is different from the conventionally employed off-the-shelf solutions which might not be best fit for a given ECS application at hand. To that end, a detailed literature review of the AMS is first conducted, to understand the underlying thermodynamic process. Then, the AMS preliminary design method is elaborated as a step-by-step thermodynamic cycle design process. The logic of the cycle design method is based on two elements: 1) free manipulation of the initial state (the bleed/atmospheric air) and the final state (ECS inlet requirements), 2) repository of typical thermodynamic processes that can be assembled in an arbitrary series to connect these two states. The AMS cycle performance (e.g. work- or exergy-based figures of merit) is calculated at each step, thus enabling the user to navigate the system architecture design space by searching for energetically-efficient cycles. Furthermore, we include other energy sources and sinks typically available on the aircraft and estimate the resulting AMS energy consumption reduction potential. Finally, once such minimum energy/entropy generation cycle/system is designed, the practical feasibility of the system for the chosen short-medium range airplane application case is evaluated, and the optimum AMS is selected.

 

Based on the analysis conducted so far, an AMS employing a turbo-mixer component is expected to improve on the performance of the conventional architecture comprised of flow control valves and a pre-cooler. However, this thermodynamic analysis is still ongoing and possibility for finding improved solutions for minimum energy consuming AMS is open. In conclusion, the contribution of the present work on the blank-sheet thermodynamic design of the AMS architecture is to help the designer in exploration of the latent subsystem design envelopes for reducing the power loads of the ECS as well as the engines.

Presenting Author: Subramanya Spurthy Safran Tech

Presenting Author Biography: Subramanya Spurthy is a second year PhD student studying low level robust modelling of commercial aircraft environmental control system under the joint tutorship between Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO) and Safran Tech. Prior to that she worked on aircraft engine pre-development as a junior consultant engineer at Capgemini Engineering. Spurthy graduated from the master’s degree in Aerospace Engineering with Aerodynamics and Propulsion major at ISAE-Supaéro in 2021, following the bachelor’s degree in Aeronautical Engineering from Nitte Meenakshi Institute of Technology in 2019. Her areas of professional interest are aircraft engine design, performance analysis, and turbomachinery.

Authors:

Subramanya Spurthy Safran Tech
Aleksandar Joksimović Institut Supérieur de l'Aéronautique et de l'Espace
Xavier Carbonneau Institut Supérieur de l'Aéronautique et de l'Espace
Sarah Rebholz Safran Tech
Frederic Tong-Yette Safran Tech