Large-eddy simulations of the non-reactive flow in the Sydney swirl burner

Abstract This paper presents a numerical investigation using large-eddy simulation. Two isothermal cases from the Sydney swirling flame database with different swirl numbers were tested. Rational grid system and mesh details were presented firstly. Validations showed overall good agreement in time averaged results. In medium swirling case, there are two reverse-flow regions with a collar-like structure between them. The existence of strong unsteady structure, precessing vortex core, was proven. Coherent structures are detached from the instantaneous field. Q -criterion was used to visualize vorticity field with distinct clear structure of vortice tubes. Dominating spatial–temporal structures contained in different cross sections were extracted using proper orthogonal decomposition. In high swirling case, there is only one long reverse-flow region. In this paper, we proved the capability of a commercial CFD package in predicting complex flow field and presented the potential of large eddy simulation in understanding dynamics.

[1]  T. O’Doherty,et al.  Vortex breakdown: a review , 2001 .

[2]  LES of the Sydney swirl flame series: A study of vortex breakdown in isothermal and reacting flows , 2007 .

[3]  S. Menon,et al.  Large eddy simulation of bluff-body stabilized swirling non-premixed flames , 2007 .

[4]  Johannes Janicka,et al.  Large-eddy simulation of a bluff-body stabilized nonpremixed flame , 2006 .

[5]  R. Barlow,et al.  Swirling turbulent non-premixed flames of methane: flow field and compositional structure , 2002 .

[6]  Y. Dubief,et al.  On coherent-vortex identification in turbulence , 2000 .

[7]  Assaad R. Masri,et al.  The compositional structure of swirl-stabilised turbulent nonpremixed flames , 2004 .

[8]  Michael P. Kirkpatrick,et al.  Study of jet precession, recirculation and vortex breakdown in turbulent swirling jets using LES , 2009 .

[9]  L. Hu,et al.  Large-Eddy Simulation of the Sydney Swirling NonPremixed Flame and Validation of Several Subgrid-Scale Models , 2008 .

[10]  Salah S. Ibrahim,et al.  LES of Recirculation and Vortex Breakdown in Swirling Flames , 2008 .

[11]  A. Masri,et al.  PRECESSION AND RECIRCULATION IN TURBULENT SWIRLING ISOTHERMAL JETS , 2004 .

[12]  Johannes Janicka,et al.  LES OF THE SYDNEY SWIRL FLAME SERIES: AN INITIAL INVESTIGATION OF THE FLUID DYNAMICS , 2007 .

[13]  Jochen Fröhlich,et al.  Identification and analysis of coherent structures in the near field of a turbulent unconfined annular swirling jet using large eddy simulation , 2006 .

[14]  R. Barlow,et al.  Turbulence–chemistry interactions in non-premixed swirling flames , 2007 .

[15]  W. Malalasekera,et al.  Large Eddy Simulations of Swirling Non-premixed Flames With Flamelet Models: A Comparison of Numerical Methods , 2008 .

[16]  Yasir M. Al-Abdeli,et al.  Time-varying behaviour of turbulent swirling nonpremixed flames , 2006 .

[17]  János M. Beér,et al.  Combustion in swirling flows: A review , 1974 .

[18]  Assaad R. Masri,et al.  Recirculation and flowfield regimes of unconfined non-reacting swirling flows , 2003 .

[19]  W. Malalasekera,et al.  Modelling of instabilities in turbulent swirling flames , 2010 .

[20]  N. Syred.  A review of oscillation mechanisms and the role of the precessing vortex core (PVC) in swirl combustion systems , 2006 .

[21]  A. Masri,et al.  Stability characteristics and flowfields of turbulent non-premixed swirling flames , 2003 .

[22]  A. Hussain.  Coherent structures—reality and myth , 1983 .

[23]  S. Ibrahim,et al.  LARGE EDDY SIMULATION OF ISOTHERMAL TURBULENT SWIRLING JETS , 2007 .

[24]  C. Duwig,et al.  Large eddy simulation of vortex breakdown/flame interaction , 2007 .