Book Description

Soot production in gas turbine combustors is not desirable since it is the major source of exhaust smoke emission and its thermal radiation to the combustor liner deteriorates the liner durability. Soot formation involves comparatively slow chemistry and equilibrium can not be applied to soot modelling in the combustor flow field. . The exact sooting process in the combustor is poorly understood given both the complexity and the limited experimental data available. The work reported in this thesis seeks to first develop in-situ techniques for retrieving spatially-resolved soot properties, mainly soot particle volume fraction, from within the combustor and also to apply the measured results to comparisons with predicted soot concentrations. Two probing methods have been demonstrated which also incorporate a laser absorption technique. The sight probe proves to be more reliable in the present measurements. The evaluation of the physical probing techniques in sooty laboratory flames reveals that the flame structure will not be substantially distorted by the probe. The disturbance caused by the probe is localised, a feature which is evident in the reported water flow visualization test. The necessary inert gas purge can be minimised to reduce the local aerodynamic perturbation. The measured soot volume fraction distributions are comparable with sooting levels reported in flame studies in the literature. The peak soot volume fractions are located off-axis, characteristic of the fuel atornization. The measurementsin the primary zone are restricted by the multi-phase character of the flow, where soot absorption can not be readily discriminated from fuel droplet scattering. Measurements are reported over a range of air-fuel ratios, inlet pressures and temperatures. Time-averageds calard istributionsa t the nominald ilution sectionh ave beeno btained in addition to the soot measuremenut sing probe sampling and standard gas analysis. Correlationso f carbond ioxide with mixtur.