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Long-Term Advanced Propulsion Concepts and Technologies


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