FLITES : Fibre-Laser Imaging of gas Turbine Exhaust Species

We propose to establish a world-leading capability in the measurement and imaging of molecular and particulate species in gas turbine aero-engine exhausts. The FLITES project proposed here will break new ground in the fundamental engineering knowledge base of measurement and imaging in the extreme environment of the turbine exhaust plume. It will enhance turbine-related R&D capacity in both academia and industry by opening up access to exhaust plume chemistry with penetrating spatio-temporal resolution. It will underpin a new phase of low-net-carbon development that is underway in aviation, based on bio-derived fuels, and which entails extensive R&D in turbine engineering, turbine combustion, and fuel product formulation.

There has never been a substantial investigation of the utility of emissions data to determine the condition and behaviour of internal engine components, especially the combustor. FLITES will open a new door to penetrate the complex phenomena that dictate the performance and limitations of advanced gas turbines, and will enable critical assessment of the performance of novel fuels. The project focuses on emissions of soot, unburned hydrocarbons (UHC) and NO, which are all regulated by certification authorities, and CO2, as a marker for assessment of individual fuel injection nozzle performance within the annular multi-nozzle combustor of an aero gas turbine.

FLITES builds upon the expertise of the UK's world-leading groups in fibre-lasers, gas-detection opto-electronics, and chemical species tomography (CST), allied to its industrial strengths in aero-engine manufacture and aviation fuel technology. High-power fibre-lasers, operating at wavelengths that give access to gaseous molecular species through vibrational-rotational absorption spectroscopy, offer radically new measurement architectures and sensitivity levels. FLITES will establish the new gas detection technology of Tunable Fibre-Laser Absorption Spectroscopy, TFLAS.

Soot will be imaged via the novel technique of near-IR continuous-wave laser-induced incandescence (CW-LII), in a planar tomographic set-up previously invented by the applicants for the fluorescence case. The high light output power available from the fibre-lasers to be demonstrated in FLITES will transform the logistics and sensitivity of CST with (relatively) large numbers of simultaneous measurement paths through the plume. Parallel threads of research will be facilitated by using near-IR diode lasers and existing mid-IR sources in single-path systems, which also mitigate against research risks. The techniques developed in the university laboratories will be implemented on a full-scale aero-engine mounted on a testbed at Rolls-Royce.

The consortium will work in intensive collaboration, directed by a management team that comprises the Principal Investigators of the three universities, two Rolls-Royce staff and one from Shell. Progress will be reviewed on a quarterly basis, and forward plans will be optimally adjusted on a half-yearly schedule.

FLITES will register strongly on all four of RCUK's major dimensions of impact:

- Knowledge economy: though stronger academic positions in fibre laser technology, gaseous measurement and imaging technology, and gas turbine diagnostics;

- Manufacturing economy: through improved gas turbine aero-engine technology, more incisive assessment of biofuel performance, development of commercial tomography and gas detection systems, and fibre lasers for gas sensing;

- Training: four PDRAs and two PhD students funded directly by FLITES, and further PhD students funded by the universities' DTA (or other) funds, and a number of staff in the partner companies;

- Society: by offering a radically new means to measure and characterise the emissions of low-level pollutants and CO2 from aero-engine turbines, making a substantial contribution towards achieving sustainable commercial aviation.

FLITES will provide industrial benefit as follows:

1. by providing information to the company partners (Covesion, Fianium, OptoSci, Rolls-Royce, Shell) in terms of:

- Performance data of fibre laser systems for gas and particulate sensing. This will enable analysis of the commercial potential of these systems;

- Electronic system design for multi-channel implementations of the above;

- First ever images of the spatial distribution of chemical species in aero-engine exhaust plumes, enabling analysis of the potential for further development of that capability;

- Data on dependence of the above spatial distributions on engine operating parameters and on bio-derived components in aviation fuel.

- Advances in the technology of TDLS instrumentation for gas turbine engine diagnostics, and for harsh environments in general.

2. by Knowledge Transfer concerning the above, to the wider industrial sectors of aero gas-turbine design and manufacturing, aviation fuel manufacturing, fibre laser and mid-IR optical technology, gas detection technology and industrial process tomography technology.

3. In the fibre laser industry, partner companies will have significant opportunities, through:

- Potential exploitation of multi-functional high-power fibre laser systems for gaseous species measurement, in tuneable systems, and exhibiting stable operation in an industrial environment;

- Extension of the market for fibre laser-based measurement systems, due to FLITES extending the technology into the mid-IR.

These opportunities promise to increase the market volume for specialist fibre laser manufacturing companies.

4. In the gas and particulate measurement industries, FLITES will generate business opportunities by:

- Creating the new technique of Tunable Fibre Laser Absorption Spectroscopy, TFLAS, applicable to many species and measurement configurations;

- Demonstrating CW-LII, opening up a broad range of new applications of the technique in the aero-engine industry and elsewhere, e.g. in atmospheric monitoring.

- Advancing the technology of TDLS instrumentation for gas turbine engine diagnostics in particular and for applications in harsh environments in general.

These represent novel ground-breaking technologies in those industries.

5. In the emerging Industrial Process Tomography industry, companies will have new high-value opportunities arising from FLITES, particularly through the extension of Chemical Species Tomography to large-scale imaging of low-concentration species, with potential for application in many measurement tasks, such as monitoring and locating dangerous gas leaks over wide areas.

6. R&D capability in the gas turbine and aviation fuel industries will be enhanced directly by the use of the techniques developed in FLITES, with a substantial increase in information available from expensive aero engine testing procedures. These advantages can be readily extended to stationary gas turbines and marine gas turbines. Since the gas turbine industry has been evolving in recent years to incorporate the provision of services as well as initial manufacture, one can envisage the use of FLITES techniques in turbine maintenance facilities, to ensure environmental and safety performance, with resultant business opportunity for all technology suppliers and system manufacturers.

7. The industrial partners will benefit directly from the training of their own staff and the availability for recruitment of the five PDRAs and (at least) two PhD students involved in FLITES.

8. In terms of wider society, FLITES offers a radically new means to measure and characterise the emissions of low-level pollutants and CO2 from aero-engines. This will make a substantial contribution towards achieving sustainable commercial aviation, e.g. by validating the overall chemical performance of fuels with large fractions of bio-derived components.