Session: 01-02: Conceptual Design and Optimization I

Submission Number: 175608

On the Coupled Sizing of Next-Generation Turbofans and Aircraft Environmental Control System 

This paper explores the impact of the integration of the environmental control system (ECS) requirements on the design of the next generation of geared turbofans for short-to-medium range applications. Conventional ECS typically utilise pneumatic systems supplied by pressurised air from a high-pressure compressor interstage bleeds. However, this solution can be energy wasteful, as the ECS mission requirements and bleed source conditions can not always be closely coupled. Alternative configurations, already in service, include electrically driven compressors either supplied with ram air or from the engine’s by-pass duct that exactly matches the ECS requirements, offering 0.6% reduction on engine-specific fuel consumption.

The aim of this paper is to address how the engine sizing is affected by each ECS configuration and propose an interchangeable design that can work with either, without compromising the cycle's maximum temperature limits, shaft speeds and compressors' surge margins. To achieve that, existing models, built in Simcentre Amesim, that couple cabin cooling and ECS are utilised to provide the necessary engine bleed and power requirements for three configurations: a conventional pneumatic system, an electrically driven compressor fed from the by-pass duct and another from ram air. Then the engine sizing is carried out with an integrated framework that comprises PROOSIS simulation environment and ATLAS (a Cranfield University in-house tool), for engine performance and weight estimation, respectively. In addition, for the interchangeable design specifically, the variable geometry of the intermediate pressure compressor and the blow-off schedules are calculated to ensure that the operating limits are met across all operating points with every ECS configuration.

Initial results suggest that engines designed specifically for the electrically driven ECS allow for a slight improvement in engine SFC. In addition, when an engine is designed for a specific ECS configuration is retrofitted with another, shaft speeds and compressor surge margins are compromised. Finally, it is demonstrated that an interchangeable design can accommodate any ECS configuration, with careful modification of the variable geometry schedule.
 

Presenting Author: Pavlos Rompokos Cranfield University

Presenting Author Biography: Pavlos Rompokos is a research fellow in the power and propulsion centre of Cranfield University School of Aerospace, Transport and Manufacture. He received an integrated master’s degree in mechanical engineering from National Technical University of Athens and an MSc and PhD in aerospace propulsion from Cranfield University. His current field of research is the implementation of hydrogen on propulsion systems for civil aviation and is contributing to the tasks of EU and ATI funded projects.

Authors:

Pavlos Rompokos Cranfield University
Raj Ghelani Rolls Royce PLC
David John Rajendran Cranfield University
Christos Mourouzidis Cranfield University
Ioannis Roumeliotis Cranfield University