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Low speed aeroacoustic test of large aircraft
model with open rotor engines

Final Report Summary - L-CROR OTS (Low speed aeroacoustic test of large aircraftmodel with open rotor engines)

Executive Summary:
In the framework of the CleanSky project designated with the acronym L-CROR OTS (Proposal Reference Number: 326003 - Call identifier: SP1-JTI-CS-2012-02-Topic addressed: JTI-CS-2012-2-SFWA-02-028) low-speed aerodynamic and aeroacoustic tests are carried out on a large CROR (Counter Rotating Open Rotor) aircraft model. The tests are performed in the open test section of the DNW-LLF low speed wind tunnel. AIRBUS has designed and manufactured a 1:7 scale model of a future A320-like aircraft with two CROR engine simulators.
Project Context and Objectives:
In the framework of the CleanSky project designated with the acronym L-CROR OTS (Proposal Reference Number: 326003 - Call identifier: SP1-JTI-CS-2012-02-Topic addressed: JTI-CS-2012-2-SFWA-02-028) low-speed aerodynamic and aeroacoustic tests are carried out on a large CROR (Counter Rotating Open Rotor) aircraft model. The tests are performed in the open test section of the DNW-LLF low speed wind tunnel. AIRBUS has designed and manufactured a 1:7 scale model of a future A320-like aircraft with two CROR engine simulators.

The test is separated into three major test groups:
• measurement with rotor blades provided by the aircraft manufacturer Airbus and under the project lead of Airbus
• measurement with rotor blades provided by the engine manufacturer SNECMA and under the project lead of SNECMA
• measurement with rotor blades provided by the engine manufacturer Rolls-Royce and under the project lead of Airbus

The main objectives for this test are as follows:
The test is meant to deliver the following information:
• Farfield and nearfield acoustic data at scale 1/7th of Z08 model.
• Propeller blade design effect assessment.
• Noise sources breakdown (left / right engine alone, both engine interactions, airframe noise by means of farfield inflow microphone data and out-of-flow farfield and phased microphone array data).
• Rotation direction effect in presence of pylon and/or incidence, by means of a symmetrical instrumentation versus plane containing flow axis and incidence/pylon axis.
• Preliminary CFD-CAA method validation with a limited amount of sensor on the blades.
• Pylon blowing assessment
• Handling quality side study for reverse thrust

Project Results:
Scientific results
For the successful execution of the test with the current wind tunnel model, equipped with 4 highly instrumented propellers a dedicated signal transmission system was developed and made available. Traditional slip ring systems would not have been able to transfer the huge amount of unsteady signals from a rotating system to the data acquisition computers.

Technological results
Performance and handling quality assessment at full span scale in a world class wind tunnel facility of a future single aisle transport aircraft equipped with counter rotating engines.

Potential Impact:
The tests have been a substantial (and critical) intermediate step in the development of a new European single aisle transport aircraft. In that respect the test cleared grounds for the preparation of a first flight of a test aircraft. Furthermore the Topic manager now is in a position to assess the efficiency of this new engine concept based on the CROR operating conditions for the tests as carried out.
Dissemination of results has been performed by the Topic Manager to the SFWA partners as part of WP2245 to validate numerical tools.
Dissemination has focused on the transfer of final test data and related foreground IPR to the Topic Manager.
DNW plans to present the approach of the test as conducted at a scientific conference in the near future.

List of Websites:
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