Long-Term Advanced Propulsion Concepts and Technologies

Background

To reduce long-distance flights, for example from Brussels to Sydney, to less than two to four hours, advanced propulsion concepts and technologies need to be identified and assessed. This requires a new flight regime with Mach numbers ranging from four to eight. At these high speeds, classical turbo-jet engines need to be replaced by advanced air-breathing engines.

Project objectives

Two major directions on a conceptual and technological level are considered: ram-compression and active compression. The latter has an upper Mach number limitation but can accelerate a vehicle up to its cruise speed. Ram-compression engines need an additional propulsion system to achieve their minimum working speed. The key objectives are the definition and evaluation of:

– different propulsion cycles and concepts for high-speed flight at Mach 4 to 8 in terms of turbine-based (TBCC: fig. 1) and rocket-based combined cycles (RBCC: fig. 2)

– critical technologies for integrated engine/aircraft performance, mass-efficient turbines and heat exchangers, high-pressure and supersonic combustion experiments and modelling.

Turbine Based Combined Cycle, Rocket Based Combined Cycle

Description of the work

A sound technological basis for the industrial introduction of innovative advanced propulsion concepts in the long term (20-25 years) will be provided, defining the most critical RTD-building blocks by developing and applying dedicated analytical, numerical and experimental tools along the following road map:

- two air-breathing engines for a commonly agreed reference vehicle(s) and trajectory point(s)

- dedicated combustion experiments on supersonic and high-pressure combustion, including potential fuels and interaction with flow-field turbulence

- modelling and validation of combustion physics on the basis of chemical kinetics and fuel spray vaporisation models and turbulence affecting the combustion

- aerodynamic experiments for major engine components (intakes, nozzles, full engines), interaction of vehicle and propulsion aerodynamics resulting in a database

- evaluation and validation of advanced turbulence models to evaluate unsteady, separated flow regimes and to develop transition models based on intermittency-related parameters

- performance prediction of contra-rotating turbines and light cryogenic fuel heat exchangers.

Expected results

The project duration of 36 months will result in:

- a definition of requirements and operational conditions on a system level for high-speed flight

- dedicated, experimental databases on supersonic and high-pressure combustion and flow phenomena specific to high-speed aerodynamics

- setting-up and validating physical models integrated into numerical simulation tools on supersonic and high-pressure combustion, turbulence and transition

- feasibility of weight performance of turbine and heat exchanger components.

Two Combined Cycle engine concepts that will be investigated for high speed cruise applications in LAPCAT.