Clean Sky 2 Joint Technical Programme

This project addresses the topic “Installed UHBR Nacelle Off-Design Performance Characteristics” as part of the Large Passenger Aircraft (LPA) Innovative Aircraft Development Platform (IADP). The main goal of LPA is to demonstrate the capabilities of new technologies to accomplish the ACARE goals with respect to the environment, fulfilling future market needs as well as improving the competitiveness of Europe’s aeronautical industries. In order to tackle effectively the challenges of the next generation of large commercial transport aircraft in the context of Horizon 2020, IADP is composed of three different areas of integrated demonstrators:

  • Platform 1: “Advanced Engine and Aircraft Configuration”
  • Platform 2: “Innovative Physical Integration Cabin – System – Structure”
  • Platform 3: “Next Generation Aircraft Systems, Cockpit and Avionics”

Platform 1 is built from six work packages: Counter-Rotating Open Rotor Demo Engine FTD (WP1.1); Advanced Engine Integration Driven Fuselage (WP1.2); Validation of Scaled Flight Testing (WP1.3); Hybrid Laminar Flow Control Large Scale Demonstration (WP1.4); Applied Technologies for Enhanced Aircraft Performance (WP1.5) and Demonstration of Radical Aircraft Configurations (WP1.6). The ODIN project is linked to WP1.5 – Applied Technologies for Enhanced Aircraft Performance of Platform 1 Advanced Engine and Aircraft Configuration, which focuses on Very High Bypass ratio (VHBR), Ultra High Bypass Ratio (UHBR) and Geared TurboFan (GTF) engines. The main added-value of this WP to the present state-of-the-art is to integrate technologies in the design process for the benefit of significant aircraft performance improvements. In particular WP1.5.2 Powerplant 2025 Integration Technologies has the objective of “defining and developing technologies which enable the physical integration of large-sized power-plant systems to the wing. Particular emphasis is put on mastering the physical effects resulting from the close-coupling of the engine to the wing and PART B. I of the Partner(s) Application/Proposal for IA/RIA/CSA (Technical Section) – ODIN 6 ground such as […] aero-acoustic effects, inflow conditions to the engine and flow circulation around the engine […].” Sebastien Dubois, LPA Project Officer at Clean Sky, mentions a key challenge of “working on the integration of the UHBR engine demonstrator onto an aircraft and to ensure that we will be minimising the potential negative coupling effects throughout that integration, which means working out the impact of close-coupling effects”. ODIN addresses these issues directly by evaluating the performance of installed novel UHBR nacelle geometries at challenging flight conditions far from the design cruise point; investigating the detrimental phenomenon of nacelle external cowl separation; quantifying nozzle suppression effects caused by the proximity of the wing to the nacelle; and measuring the impact of jet-flap interaction noise on aircraft sound levels, both for passengers & on the ground.

The following technological developments are addressed within the scope of ODIN:

  • CFD assessment of a range of novel UHBR nacelle profiles under off-design conditions, including take-off, windmill and idle, requiring parametric geometric modelling & optimisation, and validated CFD analysis tools to create candidate designs
  • A highly instrumented mid-TRL nacelle section test rig to take detail measurements of the key flow physics of external cowl separation, which is currently not understood, for CFD validation
  • High order CFD calculations to predict complex external nacelle separation under off-design conditions
  • High accuracy test measurement in an industrial transonic wind tunnel of installed fan and core exhaust Cd suppression at low flows on representative separate-jet exhaust geometry under take-off and cruise conditions
  • Measurement and computational aero-acoustics (CAA) prediction of installed jet-flap interaction noise on a separate-jet nozzle test rig in an industrial transonic wind tunnel

Using appropriate CFD predictive techniques and focused component rig tests to provide high fidelity validation data, this project will develop predictive techniques to assist in interpreting UltraFan® FTD flight test results. In addition, design rules and methods will be developed to aid enhancement of off-design novel compact UHBR nacelle
design rules.