Large Eddy Simulations of excited flames issuing from rectangular nozzles

Abstract

In the current study we assess an impact of passive and active flow control methods applied to the flames emanating from rectangular nozzles. The passive control is realised by varying a jet aspect ratio using differently shaped nozzles, while the active control relies on applying a forcing to the axial component of velocity. The analysis is performed through a series of high fidelity Large Eddy Simulations (LES) using a high order in-house solver. Combustion process is modelled using the detailed chemistry model of a hydrogen oxidation with a corresponding set of species transport equations. It is shown that the passive flow control affects the jet flames significantly only up to a moderate forcing frequency. For a high frequency excitation the effect of the aspect ratio is weak. A combination of both control methods is found as very efficient in altering important practical flame features like a lift-off height and flame shape.