Turbulence Closure Assessment in URANS of a Cold-Flow Lab-Scale Swirled Burner

Nowadays, decarbonization strategies move the attention from conventional jet fuels, namely commercial kerosene, to alternative fuels for aviation. The different physicochemical properties of the latter impact the spray evolution and, consequently, the flame characteristics under different operational phases. In this context, the availability of cost-efficient, still reliable tools which may drive computer-aided design optimization processes for aeronautical engines is of paramount importance. In particular, the unsteady Reynolds-averaged Navier-Stokes (URANS) approach may provide accurate numerical predictions about the mean velocity flow field and offer a suitable baseline for the evaporation and combustion of multi-component fuels while retaining the computational effort at a reasonable level. In this regard, we present a set of numerical simulations based on the Cambridge bluff-body swirl burner geometry. The numerical investigation presented in this study hinges on the URANS framework, exploring the wide range of closure models for the Reynolds stress tensor, to address a conical vortex breakdown regime. The main objective of the current research study is to validate the numerical setup based on the extended library of experimental measurements taken on the Cambridge configuration, taking into account the non-reacting cases. The outcomes of the numerical analysis exhibit excellent agreement with the experimental data concerning the mean velocity field. Moreover, they have allowed us to emphasize the significant influence of the chosen turbulence model on the structure of vortex breakdown.