Numerical Analysis of Radiative Heat Transfer Within a Rich-Burn, Quick-Mix, Lean-Burn Combustor

Abstract Heat transfer to the wall is a significant contributor to gas turbine engine efficiency and durability. However, understanding of the magnitude and characteristics of radiative heat transfer is still lacking, due to challenges in measuring and modeling radiation in complex combustors. As a first step towards quantitatively understanding radiative heat transfer and its relative significance compared to convective heat transfer in a realistic gas turbine combustor, we conducted a frozen-field analysis of a snapshot from the numerical solutions of a Pratt & Whitney combustor. The numerical solutions were obtained through large eddy simulations with the flame generated manifold model. Soot volume fraction is postprocessed through an empirical relation. A Monte Carlo ray tracing radiation solver is employed in the frozen-field analysis, where the composition and temperature fields are fixed in space and time. The line-by-line spectral database is employed to account for the non-gray effects of radiation. Radiative heat fluxes on the inner and outer diameter walls and the turbine-combustor interface are collected. Contribution from CO2, H2O, and soot to incident radiative flux on the walls are analyzed. It is found that soot is a major contributor to the incident heat flux to the wall, while CO2 dominates the re-absorption process within the combustor. Significant amount of radiation is crossing the turbine-combustor interface, which can add additional heat loads to the turbine vanes. Lastly, the magnitude of radiative heat flux can be comparable to that of the convective fluxes, indicating the potential significance to consider radiation in future engine designs.