Generation of Realistic Boundary Conditions at the Combustion Chamber/Turbine Interface Using Large-Eddy Simulation

Abstract

Numerical simulation of multiple components in turbomachinery applications is very CPU-demanding but remains necessary in the majority of cases to capture the proper coupling and a reliable flow prediction. During a design phase, the cost of simulation is, however, an important criterion which often defines the numerical methods to be used. In this context, the use of realistic boundary conditions capable of accurately reproducing the coupling between components is of great interest. With this in mind, this paper presents a method able to generate more realistic boundary conditions for isolated turbine large-eddy simulation (LES) while exploiting an available integrated combustion chamber/turbine LES. The unsteady boundary conditions to be used at the inflow of the isolated turbine LES are built from the modal decomposition of the database recorded at the interface between the two components of the integrated LES simulation. Given the reference LES database, the reconstructed field boundary conditions can then be compared to standard boundary conditions in the case of isolated turbine configuration flow predictions to illustrate the impact. The results demonstrate the capacity of this type of conditions to reproduce the coupling between the combustion chamber and the turbine when standard conditions cannot. The aerothermal predictions of the blade are, in particular, very satisfactory, which constitutes an important criterion for the adoption of such a method during a design phase.

Design methodology for combustor in advanced gas turbine engines: a review

“…The LES result of combustor is sensitive to the inlet/outlet condition and the wall boundary condition, and the requirements for the accuracy of the boundary condition are very high in the simulation prediction of the advanced combustors. Various methods have been proposed to improve inlet/outlet conditions while implementing coupling approaches with other components including compressors and turbines (Boudier et al , 2008; Martin et al , 2021; McGuirk, 2014). Today, 3D performance evaluation based on CFD occupies an important place in combustor design due to its comprehensiveness and reliability, and is applied to the design and development of most combustors.…”

Study of Combustor–Turbine Interactions by Performing Coupled and Decoupled Hybrid RANS-LES Simulations under Representative Engine-like Conditions

“…The authors demonstrated that, even if the results seemed to be quite insensitive to the different turbulent injections, the CFD predictions obtained by simulating the stand-alone first stage were highly impacted by the imposed mean boundary conditions, confirming the importance of employing a coupled approach or imposing boundary conditions that are as realistic as possible. As a matter of fact, in the context of the project FACTOR, Martin et al [41,42] generated a database of unsteady inlet boundary conditions under laboratory non-reactive conditions for the isolated NGV. To achieve this, the data were recorded at the interface plane between the combustor and nozzle from a fully coupled LES simulation including both components.…”