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.

Keywords

• turbomachine
• large-eddy simulation
• unsteady flows
• combustion chamber/turbine coupling
• realistic boundary conditions