Abstract
An investigation of the leading edge characteristics in lifted turbulent methane-air (gaseous) and ethanol-air (spray) diffusion flames is presented. Both combustion systems consist of a central nonpremixed fuel jet surrounded by low-speed air co-flow. Non-intrusive laser-based diagnostic techniques have been applied to each system to provide information regarding the behavior of the combustion structures and turbulent flow field in the regions of flame stabilization. Simultaneous sequential CH-PLIF/particle image velocimetry and CH-PLIF/Rayleigh scattering measurements are presented for the lifted gaseous flame. The CH-PLIF data for the lifted gas flame reveals the role that ``leading-edge'' combustion plays as the stabilization mechanism in gaseous diffusion flames. This phenomenon, characterized by a fuel-lean premixed flame branch protruding radially outward at the flame base, permits partially premixed flame propagation against the incoming flow field. In contrast, the leading edge of the ethanol spray flame, examined using single-shot OH-PLIF imaging and smoke-based flow visualization, does not exhibit the same variety of leading-edge combustion structure, but instead develops a dual reaction zone structure as the liftoff height increases. This dual structure is a result of the partial evaporation (hence partial premixing) of the polydisperse spray and the enhanced rate of air entrainment with increased liftoff height (due to co-flow). The flame stabilizes in a region of the spray, near the edge, occupied by small fuel droplets and characterized by intense mixing due to the presence of turbulent structures.
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Allen, M.G., McManus, K.R., Sonnenfroh, D.M. and Paul, P.H., Planar laser-induced-fluorescence imaging measurements of OH and hydrocarbon fuel fragments in high-pressure spray-flame combustion. Appl.Optics 34 (1995) 6287–6300.
Carter, C.D., Donbar, J.M. and Driscoll, J.F., Simultaneous CH planar laser-induced fluorescence and particle imaging velocimetry in turbulent nonpremixed flames. Appl.Phys.B 66 (1998) 129–132.
Cessou, A. and Stepowski, D., Planar laser induced fluorescence measurement of [OH] in the stabilization stage of a spray jet flame. Combust.Sci.Technol. 118 (1996) 361–381.
Cessou, A., Goix, P. and Stepowski, D., Simple description of the combustion structures in the stabilization stage of a spray jet flame. Atomization Sprays 9 (1999) 1–27.
Chung, S.H. and Lee, B.J., On the characteristics of laminar lifted flames in a nonpremixed jet. Combust.Flame 86 (1991) 62–72.
Continillo, G. and Sirignano, W.A., Counterflow spray combustion modeling. Combust.Flame 81 (1990) 325–340.
Dieke, G.H. and Crosswhite, H.M., The ultraviolet bands of OH. J.Quant.Spectrosc.Radiat. Transfer 2 (1962) 97–199.
Donbar, J.M., Driscoll, J.F. and Carter, C.D., Reaction zone structure in turbulent nonpremixed jet flames-from CH-OH PLIF images. Combust.Flame 122 (2000) 1–19.
Donbar, J.M., Driscoll, J.F. and Carter, C.D., Strain rates measured along the wrinkled flame contour within turbulent non-premixed jet flames. Combust.Flame 125 (2001) 1239–1257.
Drallmeier, J.A. and Peters, J.E., Liquid-and vapor-phase dynamics of a solid-cone pressure swirl atomizer. Atomization Sprays 4 (1994) 135–158.
Friedman, J.A. and Renksizbulut, M., Investigating a methanol spray flame interacting with an annular air jet using phase-doppler interferometry and planar laser-induced fluorescence. Combust.Flame 117 (1999) 661–684.
Greenberg, J.B. and Sarig, N., An analysis of multiple flames in counterflow spray combustion. Combust.Flame 104 (1996) 431–459.
Greenberg, J.B. and Sarig, N., Sensitivity of the mode of combustion of partially premixed spray flames to flow, transport, and evaporation effects. Atomization Sprays 7 (1997) 143–159.
Herpfer, D.C. and Jeng, S., Planar measurements of droplet velocities and sizes within a simplex atomizer. AIAA J. 35 (1997) 127–132.
Kelman, J.B. and Masri, A.R., Simultaneous imaging of temperature and OH number density in turbulent diffusion flames. Combust.Sci.Technol. 122 (1997) 1–32.
Kelman, J.B., Eltobaji, A.J. and Masri, A.R., Laser imaging in the stabilisation region of turbulent lifted flames. Combust.Sci.Technol. 135 (1998) 117–134.
Kioni, P.N., Rogg, B., Bray, K.N.C. and Liñán, A., Flame spread in laminar mixing layers: The triple flame. Combust.Flame 98 (1993) 276–290.
Lazaro, B.J. and Lasheras, J.C., Droplet dispersion and transport mechanisms in a turbulent, free shear-layer. In:Twenty-Second International Symposium on Combustion. The Combustion Institute, Pittsburgh, PA (1988) pp. 1991–1998.
Le Gal, P., Farrugia, N. and Greenhalgh, D.A., Laser sheet dropsizing of dense sprays. Optics and Laser Technology 31 (1999) 75–83.
Lee, B.J. and Chung, S.H., Stabilization of lifted tribrachial flames in a laminar nonpremixed jet. Combust.Flame 109 (1997) 163–172.
Liepmann, D. and Gharib, M., The role of streamwise vorticity in the near-field entrainment of round jets. J.Fluid Mech. 245 (1992) 643–668.
Lyons, K.M. and Watson, K.A., Partially premixed combustion in lifted turbulent jets. Combust. Sci.Technol. 156 (2000) 97–105.
MacGregor, S.A., Air entrainment in spray jets. Internat.J.Heat Fluid Flow 12 (1991) 279–283.
Marley, S.K., Welle, E.J. and Lyons, K.M., Combustion structures in lifted ethanol spray flames. ASME, J.Engrg.Gas Turbines Power (to appear).
Muñiz, L. and Mungal, M.G., Instantaneous flame-stabilization velocities in lifted-jet diffusion flames. Combust.Flame 111 (1997) 16–31.
Onuma, Y., Tsuji, T. and Ogasawara, M., Studies on the flame structure of a spray burner. Bull. JSME 17 (1974) 1296–1304.
Onuma, Y. and Ogasawara, M., Studies on the structure of a spray combustion flame. In: Fifteenth International Symposium on Combustion. The Combustion Institute, Pittsburgh, PA (1975) pp. 453–465.
Peters, N. and Williams, F.A., Liftoff characteristics of turbulent jet diffusion flames. AIAA J. 21 (1983) 423–429.
Peters, N., Turbulent Combustion. Cambridge University Press, New York (2000).
Ruetsch, G.R., Vervisch, L. and Liñán, A., Effects of heat release on triple flames. Phys.Fluids 7 (1995) 1447–1454.
Sankar, S.V., Maher, K.E., Robart, D.M. and Bachalo, W.D., Rapid characterization of fuel atomizers using an optical patternator. ASME, J.Engrg.Gas Turbines Power 121 (1999) 409–414.
Schefer, R.W., Three-dimensional structure of lifted, turbulent-jet flames. Combust.Sci. Technol. 125 (1997) 371–394.
Schefer, R.W., Flame sheet imaging using CH chemiluminescence. Combust.Sci.Technol. 126 (1997) 255–270.
Tanoff, M.A., Smooke, M.D., Osborne, R.J., Brown, T.M. and Pitz, R.W., The sensitive structure of partially premixed methane-air vs. Air counterflow flames. In: Twenty-Sixth International Symposium on Combustion. The Combustion Institute, Pittsburgh, PA (1996) pp. 1121–1128.
Vanquickenborne, L. and Van Tiggelen, A., The stabilization mechanism of lifted diffusion flames. Combust.Flame 10 (1966) 59–69.
Veynante, D., Vervisch, L., Poinsot, T., Liñán, A. and Ruetsch, G.R., Triple flame structure and diffusion flame stabilization. In: Proceedings of the Summer Program. Center for Turbulence Research, NASA Ames/Stanford University (1994) pp. 55–73.
Watson, K.A., Lyons, K.M., Donbar, J.M. and Carter, C.D., Observations on the leading edge in lifted flame stabilization. Combust.Flame 119 (1999) 199–202.
Watson, K.A., Lyons, K.M., Donbar, J.M. and Carter, C.D., Scalar and velocity field measurements in a lifted CH4-Air diffusion flame. Combust.Flame 117 (1999) 257–271.
Watson, K.A., Lyons, K.M., Donbar, J.M. and Carter, C.D., Simultaneous Rayleigh imaging and CH-PLIF measurements in a lifted jet diffusion flame. Combust.Flame 123 (2000) 252–265.
Watson, K.A., Lyons, K.M., Carter, C.D. and Donbar, J.M., Simultaneous two-shot CH planar laser-induced fluorescence and particle image velocimetry measurements in lifted CH4/Air diffusion flames. In: Twenty-Ninth International Symposium on Combustion. The Combustion Institute, Pittsburgh, PA (2002) pp. 1905–1912.
Watson, K.A., Lyons, K.M., Donbar, J.M. and Carter, C.D., Evaluating the leading-edge and local extinction in lifted-jet diffusion flames (in preparation).
Zhang, Z. and Ngendakumana, P., An experimental investigation on the fuel oil atomization by pressure atomizers. Bull.Soc.Chim.Belg. 101 (1992) 893–899.
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Marley, S., Lyons, K. & Watson, K. Leading-Edge Reaction Zones in Lifted-Jet Gas and Spray Flames. Flow, Turbulence and Combustion 72, 29–47 (2004). https://doi.org/10.1023/B:APPL.0000014906.91990.4e
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DOI: https://doi.org/10.1023/B:APPL.0000014906.91990.4e