Very-low NOx combustion concepts require a high swirl number of the flow in the combustion chamber to allow for lean burn combustion. This article deals with the influence of the resulting combustor exit swirl on the turbine aerodynamics of the first stage. This investigation is based on numerical simulations. According to the literature research additional insight into combustor-turbine interaction is achieved by taking into account a fully two dimensional inlet boundary condition. Up to now published results on combustor-turbine interaction were mostly restricted to the inhomogeneous temperature distribution at the turbine inlet. The investigations are carried out on a real engine geometry — the E3E Core 3/2 — a research project of Rolls-Royce Deutschland on lean combustion. Calculations are conducted by means of the Rolls-Royce plc code Hydra. The swirled inlet boundary condition is further scaled to test rig conditions to check for the transferability between the test rig and the real engine geometry. The results show a significant impact of the inhomogeneous turbine inflow on the stage efficiency and the thermal load. The optimization potential due to the clocking position of the combustor swirl is analyzed. The impact on the secondary flow mechanisms is analyzed with a novel visualization technique. A frequency spectrum analysis is carried out to investigate the effects of the 2D inlet boundary condition on the rotor row.

Modelling combustor turbine interaction is to be performed in an integrated simulation of a combustion chamber and the nozzle guide vane of a jet engine. Starting with an incompressible pressure based combustion CFD code, two steps are required to obtain a code that is suitable for performing such calculations. Firstly, the SIMPLE algorithm needs to be extended to all-Mach-number flows. Secondly the solution algorithm needs to be modified to deal with combustion. This paper presents the first of these steps. A solver has been developed which is capable of computing both incompressible and transonic flows. Validation of modelling compressible viscous flow is performed using experimental data. The suitability of the algorithm to highly complex geometry is demonstrated on real engine nozzle guide vane geometry and results are compared to the results of other solvers.