Swirl flows play an important role in modern combustion systems such as gas turbines, aero propulsion systems etc. Next to desirable effects such as enhanced mixing such flows often exhibit aerodynamical instabilities called precessing vortex core. The configuration under study here represents a model Gas Turbine(GT) combustion chamber and features the main properties of real gas turbine combustors: a confined swirled flow with multiple recirculation zones and reattachment points, resulting in reacting case in a partially premixed methane/air aerodynamically stabilised flame. This flame exibits also precessing vortex core (PVC). The present study especially concentrates on an evaluation of the performance of different URANS-based model-combinations in predicting this confined swirling reacting flow exhibiting such aerodynamic instabilities. For this purpose an extended Bray-Moss-Libby model and a G-equation based approach, both coupled to the mixture fraction transport equation to account for partially premixed effects, are applied. Their prediction potential in capturing partially premixed combustion properties is appraised by comparison with LDV, Raman and PLIF measurements. It turns out that the influence of the combustion model on simulation results of the flame front stabilisation or mean flow field is not obvious. Nevertheless it could be mentioned that the computation time with G-equation was approximately three times longer than with BML model due to the reinitialization needed in steady case calculations and 2 times longer in case of unsteady calculations.

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