Numerical Investigation of Transient Soot Evolution Processes in an Aero-Engine Model Combustor

Abstract

This article presents unsteady Reynolds averaged Navier–Stokes simulations (URANS) of a well-characterized aero-engine model combustor with finite-rate chemistry (FRC). The simulations give insight into the complex formation and destruction processes of soot at technically relevant conditions. It will be shown that a recently developed PAH (polycyclic aromatic hydrocarbons) and soot model is able to predict soot under complex combustion conditions at elevated pressure. Finite-rate chemistry is employed for the gas phase, a sectional approach for PAHs and a two-equation model for soot. Thus, feedback effects, such as the consumption of gaseous soot precursors by growth of soot and PAHs, are inherently captured accurately. In agreement with the experiment a precessing vortex core (PVC) is observed in the ethylene fueled combustor. This requires that the computational grid covers swirlers. The PVC intensifies mixing of fuel, primary air, and hot burned gas from the inner recirculation zone, thereby supporting flame stabilization and subsequently influencing soot. The numerical results (velocity components, temperature, and soot volume fraction) compare well with experimental data. Details of soot evolution and remaining differences to the experiment are analyzed.

Keywords:

• Confined swirling flame
• Finite-rate chemistry
• Soot modeling
• Unsteady Reynolds averaged Navier–Stokes simulations (URANS)

ACKNOWLEDGMENTS

The authors wish to thanks J.-M. Lourier for fruitful discussions. The authors also gratefully acknowledge the computing time granted on the supercomputer JUROPA (Jülich research on petaflop architectures) at Jülich Supercomputing Centre (JSC) under the NIC project number 6893.

Additional information

Funding

Part of this work was funded by the European Commission within the project Fuel Injector Research for Sustainable Transport (FIRST) under contract no. 265848.