Flame–cooling air interaction in an effusion-cooled model gas turbine combustor at elevated pressure

Abstract

The focus of this work is the investigation of flame–cooling air interaction by means of wall temperature (2D themographic phosphor thermometry), gas phase temperature (coherent anti-Stokes Raman spectroscopy), flame structure (planar laser-induced fluorescence of OH) and flow field (particle image velocimetry) measurements in an effusion-cooled single sector model gas turbine combustor. The rig is operated under close-to-reality boundary conditions, i.e., elevated combustor inlet temperature and increased system pressure. Parametric variations of important parameters, namely swirl, staging and effusion cooling air mass flow are conducted to investigate their effect on total film cooling effectiveness. Furthermore, we derive a dimensionless flame–cooling air interaction intensity parameter on the basis of OH-PLIF data. The latter revealed a higher interaction intensity for fully premixed operation at a low swirl number—a trend that is reversed for higher swirl numbers, where a partially premixed combustion mode leads to increased intensities. This trend is reflected in wall temperature as well as resulting film cooling effectiveness. Peak wall temperature varies up to $$150\,{\text {K}}$$ across all parametric variations and up to $$200\,{\text {K}}$$ in axial direction on the effusion-cooled liner for a given condition. This corresponds to a variation of total film cooling effectiveness between 0.45–0.57 and 0.45–0.62, respectively.