Hostname: page-component-8448b6f56d-mp689 Total loading time: 0 Render date: 2024-04-16T20:25:08.388Z Has data issue: false hasContentIssue false
  • English
  • Français

The evolution of local instability regions in turbulent non-premixed flames

Published online by Cambridge University Press:  15 August 2016

Y. Dagan ,
E. Arad  and
Y. Tambour
Y. Dagan*
Affiliation:
Department of Aerospace Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel Aeronautical Systems, RAFAEL, Advanced Defense Systems, Ltd., Haifa 3102102, Israel
E. Arad
Affiliation:
Aeronautical Systems, RAFAEL, Advanced Defense Systems, Ltd., Haifa 3102102, Israel
Y. Tambour
Affiliation:
Department of Aerospace Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
*
†Email address for correspondence: yuvalda@technion.ac.il
Get access Rights & Permissions [Opens in a new window]

Abstract

Unsteady turbulent flame evolution in non-premixed combustion has been computationally investigated using large eddy simulations. A simple coaxial combustion chamber, subjected to highly unsteady, turbulent recirculating flow is considered, following the experimental study of Owen et al. (Proc. Combust. Inst., vol. 16, 1976, pp. 105–117). Large-scale flame fluctuations, reported in the above experimental study, such as pulsating flames in swirling and non-swirling conditions, were identified here in our computation. New criteria for flame three-dimensional inhomogeneity are suggested and implemented in the present study, providing the ability to quantify the flame unsteadiness. Using this technique, it is shown that local, large quenched regions develop in the flame’s mixing area and rotate continuously, even when swirl is not imposed on the inlet. However, this rotation appears to be disordered, abruptly changing its direction. On the other hand, our study shows that when swirl is imposed on the inlet, a larger quenched region is identified, rotating in steady ordered rotation in the direction of the imposed swirl. In addition, large-scale radial flame fluctuations are increased downstream with the increase of swirl number. Consequently, significant correlations between radial and circumferential flame fluctuation frequencies were retrieved. Proper orthogonal decomposition analysis reveals coherent flame structures of five dominant modes that contain most of the energy in the fluctuating flame. A simplified analytical stability model is derived and implemented here to assess the hydrodynamic contribution to the flame instability; it is shown that radial fluctuations are excited by circumferential perturbations in the mixing region, providing new insight into the mechanism responsible for the onset of radial fluctuations. The computed radial flame fluctuation spectrum is predicted well using the linear stability analysis. Thus, our findings may therefore be applicable to a large class of non-premixed turbulent combustion problems.

JFM classification

Reacting Flows: Combustion Instability: Instability Reacting Flows: Turbulent reacting flows
Type
Papers
Information
Journal of Fluid Mechanics , Volume 803 , 25 September 2016 , pp. 18 - 50
Check for updates
Copyright
© 2016 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bowman, C. T., Hanson, R. K., Davidson, D. F., Gardiner, W. C., Lissianski, V., Smith, G. P., Golden, D. M., Frenklach, M. & Goldenberg, M.1995 Gri-mech 2.11, Available from http://www.me.berkeley.edu/gri_mech/, accessed March 2006.Google Scholar
Cassidy, J. J. & Falvey, H. T. 1970 Observations of unsteady flow arising after vortex breakdown. J. Fluid Mech. 41 (04), 727–736.Google Scholar
Cohen, J. & Wygnanski, I. 1987a The evolution of instabilities in the axisymmetric jet. Part 1. the linear growth of disturbances near the nozzle. J. Fluid Mech. 176, 191–219.Google Scholar
Cohen, J. & Wygnanski, I. 1987b The evolution of instabilities in the axisymmetric jet. Part 2. the flow resulting from the interaction between two waves. J. Fluid Mech. 176, 221–235.Google Scholar
Dagan, Y., Arad, E. & Tambour, Y. 2011 Some observations on flame propagation in turbulent combustion. In 49th Aerospace Science Meeting, Orlando, FL, AIAA Paper 2011-780.Google Scholar
Dagan, Y., Arad, E. & Tambour, Y. 2015 On the dynamics of spray flames in turbulent flows. Proc. Combust. Inst. 35 (2), 1657–1665.Google Scholar
Ferziger, J. H. 1983 Higher level simulations of turbulent flow. In Computational Methods for Turbulent, Transonic, and Viscous Flows (ed. Essers, J.-A.), Hemisphere.Google Scholar
Germano, M., Piomelli, U., Moin, P. & Cabot, W. 1991 A dynamic subgrid-scale eddy viscosity model. Phys. Fluids A 3 (7), 1760–1765.Google Scholar
Gupta, A. K., Lilley, D. G. & Syred, N. 1984 Swirl Flows. Abacus Press.Google Scholar
Ham, F., Apte, S., Iaccarino, G., Wu, X., Herrmann, M., Constantinescu, G., Mahesh, K. & Moin, P. 2003 Unstructured les of reacting multiphase flows in realistic gas turbine combustors. Center for Turbulence Research Annual Research Briefs.Google Scholar
Ihme, M., Chong, M. C. & Pitsch, H. 2005 Prediction of local extinction and re-ignition effects in non-premixed turbulent combustion using a flamelet/progress variable approach. Proc. Combust. Inst. 30, 793–800.Google Scholar
Ihme, M. & Pitsch, H. 2008 Prediction of extinction and reignition in nonpremixed turbulent flames using a flamelet/progress variable model. Combust. Flame 155, 70–89.Google Scholar
Khorrami, M. R., Malik, M. R. & Ash, R. L. 1989 Application of spectral collocation techniques to the stability of swirling flows. J. Comput. Phys. 81 (1), 206–229.CrossRefGoogle Scholar
Kim, W. & Syed, S.2004 Large-eddy simulation needs for gas-turbine combustor design. AIAA Paper 0331.Google Scholar
Lessen, M., Sadler, S. G. & Liu, T. Y. 1968 Stability of pipe Poiseuille flow. Phys. Fluids 11 (7), 1404–1409.Google Scholar
Matalon, M. 2007 Intrinsic flame instabilities in premixed and nonpremixed combustion. Annu. Rev. Fluid Mech. 39, 163–191.Google Scholar
Mongia, H.2003 Recent advances in the development of combustor design tools. AIAA Paper 2003-4495.Google Scholar
Oberleithner, K., Sieber, M., Nayeri, C. N., Paschereit, C. O., Petz, C., Hege, H.-C., Noack, B. R. & Wygnanski, I. 2011 Three-dimensional coherent structures in a swirling jet undergoing vortex breakdown: stability analysis and empirical mode construction. J. Fluid Mech. 679, 383–414.Google Scholar
Olbricht, C., Stein, O. T., Janicka, J., van Oijen, J. A., Wysocki, S. & Kempf, A. M. 2012 LES of lifted flames in a gas turbine model combustor using top-hat filtered pfgm chemistry. Fuel 96, 100–107.Google Scholar
Olendraru, C. & Sellier, A. 2002 Viscous effects in the absolute–convective instability of the batchelor vortex. J. Fluid Mech. 459, 371–396.Google Scholar
Owen, F. K., Spadaccini, L. J. & Bowman, C. T. 1976 Pollutant formation and energy release in confined turbulent diffusion flames. Proc. Combust. Inst. 16, 105–117.CrossRefGoogle Scholar
Peters, N. 1984 Laminar diffusion flamelet models in non-premixed turbulent combustion. Prog. Energy Combust. Sci. 10 (3), 319–339.Google Scholar
Pierce, C. D. & Moin, P. 1998 Method for generating equilibrium swirling inflow conditions. AIAA J. 36, 1325–1327.Google Scholar
Pierce, C. D. & Moin, P. 2004 Progress-variable approach for large-eddy simulation of non-premixed turbulent combustion. J. Fluid Mech. 504, 73–97.Google Scholar
Pierce, C. D. & Moin, P.2001 Progress-variable approach for large eddy simulation of turbulent combustion. PhD thesis, Stanford University.Google Scholar
Pitsch, H. & Steiner, H. 2000 Scalar mixing and dissipation rate in large-eddy simulations of non-premixed turbulent combustion. Proc. Combust. Inst. 28, 2029–2037.Google Scholar
Schefer, R. W. 1997 Three-dimensional structure of lifted, turbulent-jet flames. Combust. Sci. Technol. 125 (1), 371–394.CrossRefGoogle Scholar
See, Y. C. & Ihme, M. 2014 Effects of finite-rate chemistry and detailed transport on the instability of jet diffusion flames. J. Fluid Mech. 745, 647–681.CrossRefGoogle Scholar
See, Y. C. & Ihme, M. 2015 Large eddy simulation of a partially-premixed gas turbine model combustor. Proc. Combust. Inst. 35 (2), 1225–1234.CrossRefGoogle Scholar
Shunn, L. & Moin, P.2009 Large-eddy simulations of combustion systems with convective heat-loss. Tech. Rep. TF-111. Flow Physics and Computational Engineering Group, Department of Mechanical Engineering, Stanford University.Google Scholar
Sirovich, L. 1987 Turbulence and the dynamics of coherent structures. Part i: coherent structures. Q. Appl. Maths 45 (3), 561–571.Google Scholar
Syred, N. 2006 A review of oscillation mechanisms and the role of the precessing vortex core (pvc) in swirl combustion systems. Prog. Energy Combust. Sci. 32, 93–161.Google Scholar
You, D., Ham, F. & Moin, P. 2008 Large-eddy simulation analysis of turbulent combustion in a gas turbine engine combustor. Center of Turbulence Research Annual Research Briefs.Google Scholar