Working towards cleaner air travel: the technology behind the FLITES project

With greater restrictions on airborne pollutants the aerospace industry is working towards the reduction in emission through the introduction of alternative fuels and improved engine efficiency. Another key target for the industry is cost reduction in emissions testing combined with improved measurement accuracy of pollutant species. This can be achieved by replacing the current extractive sampling systems with in-situ species concentration monitoring using optical diagnostic techniques. The Fibre Laser Imaging of Turbine Exhaust Species project brings together the Universities of Strathclyde, Edinburgh, Southampton and Manchester and industrial partners Rolls-Royce, Shell and INTA. One of the aims of this project is to produce a 2-dimensional tomographic map of the engine exhaust based on the concentration and temperature of CO2. This has required significant development, including an innovative optical distribution network, a complex data acquisition system and novel signal processing techniques. In this paper the current status of the CO2 imaging system is presented, which uses the 2f/1f normalisation technique developed by the Hanson group (need ref). This includes validation tests of CO2 concentration and plume temperature on a small turbofan engine at the Rolls-Royce facility in East Kilbride, Scotland, that shows a high degree of correlation to engine thrust. The first data from ‘phantom’ tests at the test facility at INTA, Madrid are also shown, where CO2 concentration from a controlled emission source is mapped using a complex beam configuration. Finally, the overall status of the full 126 beam imaging system will be presented.