Gas turbine emissions are indicated to be an environmental and local air quality problem. NOx, SOx and CO2 are linked with various greenhouse phenomena, and particulate matter (PM) is a local air quality issue. The measurement of PM is currently based on Smoke Number (SN), an outdated reflectance scale. A dual fuel Dry Low Emissions (DLE) combustor has been tested, with a focus on qualifying NOx emission processes. An alternative fuel (diesel) was used to generate a 3D data-set under gas turbine-relevant conditions, enabling the confirmation of CFD models for liquid-fuel combustion. Sampling line configurations were investigated to provide the aircraft engine manufacturing industry with a modern methodology of quantifying PM. Observations between different flow regimes and temperatures with PM size distributions show significant differences. The Differential Mobility Spectrometer (DMS500), a fast mobility sizer, was commissioned on an atmospheric pressure rig, using aviation-grade kerosene, to define the PM sampling methodology. On legacy combustors and a modern lean burn combustor, PM size, number and mass from the DMS500 were compared to other instruments and methodologies (i.e. TEM, CPCs, AD-MAAP) showing good correlation. Poor agreement was noted with gravimetric analysis. Size distribution comparisons between DMS500 and a scanning mobility particle sizer (SMPS) contain significant variations, due to residence time and particle condensation from the SMPS sampling configuration. Generally, engine exhaust aerosol size distribution was observed to be bimodal with a peak at 15-25nm and a peak at around 50-80nm. Finally, a large civil gas turbine was tested using emission certification representative sampling methodology. Real time sizing data showed good reproducibility, identifying both nucleation and accumulation mode PM. Good agreement was found with mass measurement on the first-order approximation (FOA3.0) SN correlation and the DMS500, whereas the MAAP failed to track the engine conditions without a correction. The sample line temperature, residence time and dilution affect the size distribution of the PM measured from engine exhaust aerosol. Quantitative size analysis of PM under controlled sampling conditions shows good reproducibility, though the effects of volatile organic matter losses need to be quantified further. Insight was developed into the formation processes of combustion product species within a DLE combustor.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:585012 |
| Date | January 2010 |
| Creators | Sevcenco, Yura Alexander |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/55079/ |
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