Influence of effusion cooling air on the thermochemical state of combustion in a pressurized model single sector gas turbine combustor

Abstract

Abstract Thermochemical interaction – represented by CO mole fraction and gas phase temperature measurements – between flame and cooling air is investigated in a close-to-reality effusion-cooled single sector model gas turbine combustor. To investigate the influence of effusion cooling air mass flow on the thermochemical state, a parametric study is conducted. Temperature measurements are performed using ro-vibrational N 2 coherent anti-Stokes Raman spectroscopy (CARS). CO mole fraction is measured by means of quantitative CO two-photon laser-induced fluorescence (CO-LIF) using a temperature dependent calibration acquired in an adiabatic pressurized laminar flame. Significantly different thermochemical states are observed in the inner and outer shear layer of the swirl stabilized flame. Within the primary zone, increasing cooling air mass flow leads to decreased CO concentrations. Close to the effusion cooled liner, the interaction varies with axial coordinate. In the outer recirculation zone, increased CO mole fractions were measured with increasing cooling air mass flow, indicating occurrence of chemical quenching in the late oxidation branch in the CO-T diagram. Further downstream, processes are dominated by mixing and CO concentrations decrease with the amount of supplied effusion cooling air. To our best knowledge, this is the first time that these effects has been shown experimentally.