Comparison of RANS and LES turbulence models for predicting air-coal and oxy-coal combustion behaviours

It is commonly accepted that with existing physical sub-models, computational fluid dynamics (CFD) can offer significant insight to the complex combustion systems such as those found in the coal-fired power generation industry. With the growth of computing resources and, in particular, the availability of powerful computer clusters, application of Large Eddy Simulation (LES) emerges as an attractive option in modelling of turbulence combustions in coal-fired furnaces. This paper presents the results from a CFD simulation of the coal combustion processes, under both air-fired and oxy-fired conditions in a 1 MWth industrial combustion test facility. Both Reynolds Averaged Navier–Stokes (RANS) and LES approaches have been employed and the results are compared with each other and with experimental measurements. Advantages of the LES underlining its potential for future industrial applications are addressed. It is shown that validation a CFD model that is based on LES requires more detailed experimental data from well-controlled experimental measurements.