Prediction of flow through swirl generator and validation by measured data

It is a well-recognized fact that reliable predictions of turbulent swirling nonpremixed flames are very difficult, especially for practical cases where application of LES methods is not feasible. It is also clear that detailed measured data of inlet velocity profiles for swirling combustion air are unavailable in practical applications. Therefore there is a need for validation of industry-standard codes for the prediction of flow through swirl generators. In this work are predictions validated by published experimental data for a swirler with guide vanes, which is similar to a typical flame holder in a staged-gas low-NOx burner. Computations are done in ANSYS Fluent v12 code using a range of frequently used moment-closure turbulence models. Impact of grid type and quality is investigated. Discussion of the results is confronted with previously published observations on this topic. The aim is to critically evaluate the applicability of computations to determine inlet boundary conditions for swirling air in industrial combustors.