Aircraft

The operational testing of Glenn's refurbished open rotor propulsion rig will begin in the first week of next year. In co-operation with General Electric, NASA is to analyse open rotor designs it started developing with industry during the 1980s.

The agency will use its latest computational technology to measure the performance again. One-sixth scale open rotor rigs that had been put into storage 15 years ago are to under go the wind tunnel re-testing.

NASA signed a space act agreement with GE on 23 July for the collaborative research, which begins with the agency repairing, updating and refurbishing the rig. Using the rig open rotor models will be re-examined using computational fluid dynamics (CFD) software and non-intrusive systems such as lasers.

The lasers are part of a measurement system and the technique is called digital particle image velocimetry. A laser sheet illuminates smoke released into the flow field surrounding the simulated support pylon and nacelle and both fan rotors.

Digital particle image velocimetry is used to measure the turbulence in the flow surrounding the model and to determine the origin and destination of the turbulence. The technique will help explain this region's flow physics and identify the propulsion system's contributing noise sources.

"We are looking at the baseline open rotor geometry. We have better [CFD software] and laser [measurement systems] today," says NASA's fundamental aeronautics programme's senior technical advisor, Anthony Strazisor, speaking at the American Institute of Aeronautics and Astronautics' 44th Joint Propulsion Conference in Hartford, Connecticut.

The rig will be placed inside Glenn's 3 x 4.6m (9 x 15ft) low-speed wind tunnel. This is NASA's primary facility for measuring the acoustic characteristics and aerodynamic performance of simulated, scale-model aircraft propulsion systems. The rigs were originally tested in this anechoic wind tunnel.