Large-eddy simulations as a design tool for gas turbine combustion systems

In recent years, large-eddy simulation (LES) has emerged as a promising next-generation computational tool for design applications. Compared to Reynolds-averaged Navier-Stokes simulation, the advantages that LES offers, in terms of improved turbulent mixing and ability to predict unsteady phenomena, makes it attractive for gas turbine combustor applications. An overview of recent activities related to LES being pursued at Rolls-Royce is provided. The LES methodology is reviewed both from numerical and modeling perspectives. The state of the art in subgrid-scale (SGS) modeling and spray modeling is discussed. Recently developed SGS reaction-rate closures such as the transport filtered density function method are reviewed and discussed. Validation experiments performed on several benchmark flows (nonreacting and reacting) and practical gas turbine combustor configurations are presented. Finally, ongoing developments for improving the LES methodology are highlighted.