Book Description

Efficient aeronautical engines operate at higher pressure ratios and temperature, creating challenges due to higher heat loads. Thermal radiation in aviation has conventionally been treated as correction factors or scaled from experimental data. The complexity of the radiative transfer equation (RTE) leads to computational costly solutions resulting in simplified treatment. The goal of this work is to extend knowledge of non-gray gas radiation modeling to gas-turbine combustor simulations under high-pressure conditions. A one-dimensional temperature solver for combustor liners with thermal barrier coating is developed first, and a non-gray wide-band spectral model for high-pressure conditions is constructed subsequently. Both retrieve spectral properties of combustion gases from high-resolution spectroscopy databases and a Monte Carlo ray tracing solver is used to provide accurate solution of RTE in the gas phase. Frozen-field analysis of a model gas turbine combustor shows heat fluxes concentrated downstream of the main flame brush. Increase of pressure from 1 bar to 40 bar enhances peak radiation loads to the wall by approximately ten folds. A wide-band model is subsequently proposed for gas and soot under pressurized conditions. Improvement in radiative flux prediction is observed when the band definition is carefully chosen around radiative emission peaks, although overall the wide-band model approximates the gray solutions obtained using the MCRT solver closely. Further research is needed to better characterize liner temperature by considering more realistic radiative and convective heat load and TBC parameters. Improvement of the wide-band model is required to better predict the non-gray radiative heat load to the wall.