Abstract

VIGUERAS-ZUNIGA, M.O.; VALERA-MEDINA, A.  and  SYRED, N.. Studies of the Precessing Vortex Core in Swirling Flows. J. appl. res. technol [online]. 2012, vol.10, n.5, pp.755-765. ISSN 2448-6736.

Large scale coherent structures play an important role in the behavior of the combustion regime inside any type of combustor stabilized by swirl, with special impact on factors such as flame stability, blow off, emissions and the occurrence of thermo-acoustic oscillations. Lean premixed combustion is widely used and is known to impact many of these factors, causing complex interrelationships with any coherent structure formed. Despite the extensive experimentation in this matter, the above phenomena are poorly understood. Numerical simulations have been used to try to explain the development of different regimes, but their extremely complex nature and lack of time dependent validation show varied and debatable results. The precessing vortex core (PVC) is a well-known coherent structure whose development, intensity and occurrence has not been well documented. This paper thus adopts an experimental approach to characterize the PVC in a simple swirl burner under combustion conditions so as to reveal the effects of swirl and other variables on the latter. Aided by a high speed photography (HSP) system, the recognition and extent of several different types of PVCs were observed and discussed.

Keywords : swirling flows; PVC; high speed photography.