Large-eddy simulation of turbulent flow inside a sudden-expansion cylindrical chamber

Abstract

A large-eddy simulation (LES) is performed for turbulent flow inside a combustion device. The combustion device is simplified as a cylinder with sudden expansion. To promote turbulent mixing and to accommodate flame stability, a flame holder is attached inside the combustion chamber. Emphasis is placed on the flow details with different geometries of the flame holder. The Smagorinsky model and the Lagrangian dynamic subgrid-scale model are applied and tested. The simulation code is constructed using a general coordinate system based on the physical contravariant velocity components. The calculated Reynolds numbers are 5000 and 50 000 based on the bulk velocity and the diameter of the inlet pipe. The predicted turbulent statistics are evaluated by comparing with the experimental data, which are obtained by laser Doppler velocimetry. The agreement of the LES with the experimental data is shown to be satisfactory.